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<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" [
<!ENTITY app "<application>Genius Mathematics Tool</application>">
<!ENTITY appname "Genius">
<!ENTITY appversion "1.0.27">
<!ENTITY date "October 2021">
<!ENTITY legal SYSTEM "legal.xml">
<!ENTITY manrevision "0.2">
<!ENTITY lt "&#60;">
<!ENTITY gt "&#62;">
<!ENTITY le "&#8804;">
<!ENTITY ge "&#8805;">
<!ENTITY lsquo "&#8216;">
<!ENTITY rsquo "&#8217;">
<!--<!ENTITY gel-function-list SYSTEM "gel-function-list.xml">-->]>
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      (Do not remove this comment block.)
  Maintained by the GNOME Documentation Project
  http://developer.gnome.org/projects/gdp
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<!-- =============Document Header ============================= -->
<book id="index" lang="messages">
<!-- please do not change the id; for translations, change lang to -->
<!-- appropriate code -->
  <bookinfo>
	  <abstract role="description"><para>Manuel de l'Outil de maths Genius.</para></abstract>
    <title>Manuel de Genius</title>       

    <copyright lang="en">
      <year>1997-2021</year>
      <holder>Jiří (George) Lebl</holder>
    </copyright>
    <copyright lang="en">
      <year>2004</year>
      <holder>Kai Willadsen</holder>
    </copyright>
<!-- translators: uncomment this:
  <copyright>
   <year>2002</year>
   <holder>ME-THE-TRANSLATOR (Latin translation)</holder>
  </copyright>
-->

    <publisher> 
      <publishername/> 
    </publisher> 

     <legalnotice id="legalnotice">
	<para>Permission vous est donnée de copier, distribuer et/ou modifier ce document selon les termes de la Licence GNU Free Documentation License, Version 1.1 ou ultérieure publiée par la Free Software Foundation sans section inaltérable, sans texte de première page de couverture ni texte de dernière page de couverture. Vous trouverez un exemplaire de cette licence en suivant ce <ulink type="help" url="ghelp:fdl">lien</ulink> ou dans le fichier COPYING-DOCS fourni avec le présent manuel.</para>
         <para>Ce manuel fait partie de la collection de manuels GNOME distribués selon les termes de la licence de documentation libre GNU. Si vous souhaitez distribuer ce manuel indépendamment de la collection, vous devez joindre un exemplaire de la licence au document, comme indiqué dans la section 6 de celle-ci.</para>

	<para>La plupart des noms utilisés par les entreprises pour distinguer leurs produits et services sont des marques déposées. Lorsque ces noms apparaissent dans la documentation GNOME et que les membres du projet de Documentation GNOME sont informés de l'existence de ces marques déposées, soit ces noms entiers, soit leur première lettre est en majuscule.</para>

	<para lang="en">
	  DOCUMENT AND MODIFIED VERSIONS OF THE DOCUMENT ARE PROVIDED
	  UNDER  THE TERMS OF THE GNU FREE DOCUMENTATION LICENSE
	  WITH THE FURTHER UNDERSTANDING THAT:

	  <orderedlist>
		<listitem>
		  <para lang="en">DOCUMENT IS PROVIDED ON AN "AS IS" BASIS,
                    WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR
                    IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
                    THAT THE DOCUMENT OR MODIFIED VERSION OF THE
                    DOCUMENT IS FREE OF DEFECTS MERCHANTABLE, FIT FOR
                    A PARTICULAR PURPOSE OR NON-INFRINGING. THE ENTIRE
                    RISK AS TO THE QUALITY, ACCURACY, AND PERFORMANCE
                    OF THE DOCUMENT OR MODIFIED VERSION OF THE
                    DOCUMENT IS WITH YOU. SHOULD ANY DOCUMENT OR
                    MODIFIED VERSION PROVE DEFECTIVE IN ANY RESPECT,
                    YOU (NOT THE INITIAL WRITER, AUTHOR OR ANY
                    CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
                    SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER
                    OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
                    LICENSE. NO USE OF ANY DOCUMENT OR MODIFIED
                    VERSION OF THE DOCUMENT IS AUTHORIZED HEREUNDER
                    EXCEPT UNDER THIS DISCLAIMER; AND
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		  <para lang="en">UNDER NO CIRCUMSTANCES AND UNDER NO LEGAL
                       THEORY, WHETHER IN TORT (INCLUDING NEGLIGENCE),
                       CONTRACT, OR OTHERWISE, SHALL THE AUTHOR,
                       INITIAL WRITER, ANY CONTRIBUTOR, OR ANY
                       DISTRIBUTOR OF THE DOCUMENT OR MODIFIED VERSION
                       OF THE DOCUMENT, OR ANY SUPPLIER OF ANY OF SUCH
                       PARTIES, BE LIABLE TO ANY PERSON FOR ANY
                       DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR
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                       INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS
                       OF GOODWILL, WORK STOPPAGE, COMPUTER FAILURE OR
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                       EVEN IF SUCH PARTY SHALL HAVE BEEN INFORMED OF
                       THE POSSIBILITY OF SUCH DAMAGES.
		  </para>
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	</para>
  </legalnotice>


   <!-- This file  contains link to license for the documentation (GNU FDL), and 
        other legal stuff such as "NO WARRANTY" statement. Please do not change 
	any of this. -->

    <authorgroup> 
      <author role="maintainer" lang="en"> 
		<firstname>Jiří</firstname> 
		<surname>Lebl</surname> 
		<affiliation> 
	  		<orgname>Oklahoma State University</orgname> 
	  		<address> <email>jiri.lebl@gmail.com</email> </address> 
		</affiliation> 
      </author> 
      <author lang="en"> 
		<firstname>Kai</firstname> 
		<surname>Willadsen</surname> 
		<affiliation> 
	  		<orgname>University of Queensland, Australia</orgname> 
	  		<address> <email>kaiw@itee.uq.edu.au</email> </address> 
		</affiliation> 
      </author> 
      
<!-- This is appropriate place for other contributors: translators,
     maintainers,  etc. Commented out by default.
     
      <othercredit role="translator">
		<firstname>Latin</firstname> 
		<surname>Translator 1</surname> 
		<affiliation> 
	  		<orgname>Latin Translation Team</orgname> 
	  		<address> <email>translator@gnome.org</email> </address> 
		</affiliation>
		<contrib>Latin translation</contrib>
      </othercredit>
-->
    </authorgroup>


<!-- According to GNU FDL, revision history is mandatory if you are -->
<!-- modifying/reusing someone else's document.  If not, you can omit it. -->
<!-- Remember to remove the &manrevision; entity from the revision entries other
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      ugly and we don't update the manrevision stuff anyway
    <revhistory>
      <revision> 
		<revnumber>&manrevision;</revnumber> 
		<date>&date;</date> 
		<revdescription> 
	  		<para role="author">Jiri (George) Lebl
	    	<email>jirka@5z.com</email>
	  		</para>
		</revdescription> 
      </revision> 
      <revision> 
		<revnumber>0.1</revnumber> 
		<date>September 2004</date> 
		<revdescription> 
	  		<para role="author">Kai Willadsen
	    	<email>kaiw@itee.uq.edu.au</email>
	  		</para>
		</revdescription> 
      </revision> 
      <revision> 
		<revnumber>Genius Calculator Manual</revnumber> 
		<date>August 2004</date> 
		<revdescription> 
	  		<para role="author">Jiri (George) Lebl
	    	<email>jiri.lebl@gmail.com</email>
	  		</para>
		</revdescription> 
      </revision> 
    </revhistory> 
-->

    <revhistory>
      <revision lang="en"> 
		<revnumber>0.2</revnumber> 
		<date>October 2021</date> 
		<revdescription> 
	  		<para role="author" lang="en">Jiri (George) Lebl
	    	<email>jiri.lebl@gmail.com</email>
	  		</para>
		</revdescription> 
      </revision> 
    </revhistory>
    <releaseinfo lang="en">This manual describes version 1.0.27 of Genius.
    </releaseinfo> 
    <legalnotice> 
      <title>Votre avis</title> 
      <para lang="en">
	      To report a bug or make a suggestion regarding the <application>Genius Mathematics Tool</application>
	      application or this manual, please visit the
	      <ulink url="http://www.jirka.org/genius.html" type="http">Genius
		      Web page</ulink>
	      or email me at <email>jiri.lebl@gmail.com</email>.
      </para>
<!-- Translators may also add here feedback address for translations -->
    </legalnotice> 
  </bookinfo> 

<!-- ============= Introduction =============================== -->
  <chapter id="genius-introduction"> 
    <title>Introduction</title> 
    <para lang="en">
	The <application>Genius Mathematics Tool</application> application is a general calculator for use as a desktop
        calculator, an educational tool in mathematics and other STEM fields,
	and has found use in research.  The language used in <application>Genius Mathematics Tool</application> is designed to be
	‘mathematical’ in the sense that it should be ‘what
	you mean is what you get’.  Of course, that is not an
	entirely attainable goal.  <application>Genius Mathematics Tool</application> features rationals, arbitrary
	precision integers and multiple precision floats using the GMP library.
	It handles complex numbers using cartesian notation.  It has good
	vector and matrix manipulation and can handle basic linear algebra.
	The programming language allows user defined functions, variables, and
	parameters.
    </para> 

    <para lang="en">
	<application>Genius Mathematics Tool</application> comes in two versions.  One version is the graphical GNOME
	version, which features an IDE style interface and the ability 
	to plot functions of one or two variables.  Parametric plots of curves
	are also supported.  It can plot slope fields,
	vector fields and draw their solutions.  The plots can be exported
	to several formats.
	The command line version does not require GNOME, but
	does not implement any feature that requires the graphical interface,
	such as plotting
    </para> 

    <para lang="en">
	    Parts of this manual describe the graphical version of the calculator.
	    The language that both versions use is the same, it is simply the
	    graphical features such as plotting that are unique to the GUI version.
    </para>

    <para lang="en">
	    Generally, when some feature of the language (function, operator, etc...)
	    is new in some version past 1.0.5, it is mentioned, but
	    below 1.0.5 you would have to look at the NEWS file.
    </para>

  </chapter>

<!-- =========== Getting Started ============================== -->
  <chapter id="genius-getting-started"> 
    <title>Premiers pas</title> 

    <sect1 id="genius-to-start">
      <title>Lancement de l'<application>Outil de maths Genius</application></title>
      <para lang="en">You can start <application>Genius Mathematics Tool</application> in the following ways:
      </para> 
      <variablelist>
        <varlistentry>
          <term>Menu <guimenu>Applications</guimenu></term>
          <listitem>
	    <para>En fonction de votre système d'exploitation et de sa version, l'élément de menu pour l'<application>Outil de maths Genius</application> peut apparaître à différents endroits. Cela peut être dans les sous-menus <guisubmenu>Éducation</guisubmenu>, <guisubmenu>Accessoires</guisubmenu>, <guisubmenu>Bureautique</guisubmenu>, <guisubmenu>Science</guisubmenu> ou d'autres similaires en fonction de vos réglages personnels. Le nom de l'entrée de menu que vous recherchez est <application>Outil de maths Genius</application>. Une fois localisé, cliquez dessus pour démarrer l'<application>Outil de maths Genius</application>.</para>
	      </listitem>
        </varlistentry>
        <varlistentry>
          <term>Boîte de dialogue <guilabel>Lancer une application</guilabel></term>
          <listitem>
	    <para>Il se peut que l'entrée de menu ne soit pas accessible pour votre système d'exploitation. Dans ce cas, vous pouvez ouvrir la boîte de dialogue <guilabel>Lancer une application</guilabel> et saisir <command>gnome-genius</command>.</para>
	      </listitem>
        </varlistentry>
        <varlistentry>
    	  <term>Ligne de commande</term>
    	  <listitem>
    	    <para>Pour démarrer la version GNOME de l'<application>Outil de maths Genius</application>, saisissez <command>gnome-genius</command>.</para>
	    <para>Pour démarrer seulement la version en ligne de commande, exécutez la commande <command>genius</command>. Cette version ne comprend pas d'environnement graphique et certaines fonctionnalités comme le tracé de graphiques ne sont pas disponibles.</para> 
          </listitem>
        </varlistentry>
      </variablelist>
    </sect1>

    <sect1 id="genius-when-start">
    <title>Démarrage de Genius</title>
      <para>Lorsque vous démarrez la version GNOME de l'<application>Outil de maths Genius</application>, la fenêtre <xref linkend="mainwindow-fig"/> apparaît.</para>

      <figure id="mainwindow-fig"> 
        <title>Fenêtre de l'<application>Outil de maths Genius</application></title> 
        <screenshot> 
          <mediaobject lang="en"> 
            <imageobject>
              <imagedata fileref="figures/genius_window.png" format="PNG" scalefit="1"/> 
            </imageobject>
            <textobject> 
	      <phrase>Shows <application>Genius Mathematics Tool</application> main window. Contains titlebar, menubar,
toolbar and working area. Menubar contains <guilabel>File</guilabel>,
<guilabel>Edit</guilabel>, <guilabel>Calculator</guilabel>,
<guilabel>Examples</guilabel>,
<guilabel>Programs</guilabel>,
<guilabel>Settings</guilabel>, and <guilabel>Help</guilabel> menus.</phrase> 
            </textobject> 
          </mediaobject>
        </screenshot> 
      </figure>

      <para>La fenêtre de l'<application>Outil de maths Genius</application> contient les éléments suivants :</para>
      <variablelist>
        <varlistentry>
          <term>Barre de menus</term>
          <listitem>
            <para>Les menus de la barre de menus contiennent toutes les commandes dont vous aurez besoin pour travailler avec les fichiers dans l'<application>Outil de maths Genius</application>. Le menu <guilabel>Fichier</guilabel> contient les éléments pour charger et enregistrer des éléments et créer de nouveaux programmes. La commande <guilabel>Charger et exécuter...</guilabel> n'ouvre pas de nouvelle fenêtre pour le programme mais exécute seulement le programme directement. Elle est équivalente à la commande <command>load</command>.</para>
	    <para lang="en">
		The <guilabel>Calculator</guilabel> menu controls the
calculator engine.  It allows you to run the currently selected program or to
interrupt the current calculation.  You can also look at the full expression of
the last answer (useful if the last answer was too large to fit onto the
console), or you can view a listing of the values of all user defined
variables.  You can also monitor user variables, which is especially useful
while a long calculation is running, or to debug a certain program.
		    Finally the <guilabel>Calculator</guilabel> allows plotting functions using a user friendly dialog box.
	   </para>
	   <para lang="en">
		   The <guilabel>Examples</guilabel> menu is a list of example
		   programs or demos.  If you open the menu, it will load the
		   example into a new program, which you can run, edit, modify,
		   and save.  These programs should be well documented
		   and generally demonstrate either some feature of <application>Genius Mathematics Tool</application>
		   or some mathematical concept.
	   </para>
	   <para lang="en">
		   The <guilabel>Programs</guilabel> menu lists
		   the currently open programs and allows you to switch
		   between them.
	   </para>
	   <para>Les autres menus contiennent les mêmes fonctions classiques qui apparaissent dans d'autres applications.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>Barre d'outils</term>
          <listitem>
            <para>La barre d'outils contient un sous-ensemble des commandes accessibles à partir de la barre de menus.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>Zone de travail</term>
          <listitem>
            <para>La zone de travail est la principale méthode d'interaction avec l'application.</para>
	    <para lang="en">
	    	The working area initially has just the <guilabel>Console</guilabel> tab, which is
		the main way of interacting with the calculator.  Here you
		type expressions and the results are immediately returned
		after you hit the Enter key.
	    </para>
	    <para lang="en">
	    	Alternatively you can write longer programs and those can
		appear in separate tabs.  The programs are a set of commands or
	        functions that can be run all at once rather than entering them
		at the command line.  The programs can be saved in files for later
		retrieval.
	    </para>
          </listitem>
        </varlistentry>
      </variablelist>
    </sect1>

  </chapter>

<!-- ================ Usage =================================== -->
  <chapter id="genius-usage"> 
    <title>Utilisation de base</title> 

    <sect1 id="genius-usage-workarea"> 
      <title>Utilisation de la zone de travail</title> 

      <para lang="en">
        Normally you interact with the calculator in the <guilabel>Console</guilabel> tab of the
	work area.  If you are running the text only version then the console
	will be the only thing that is available to you.  If you want to use
	<application>Genius Mathematics Tool</application> as a calculator only, just type in your expression in the console, it
	will be evaluated, and the returned value will be printed.
      </para>

      <para lang="en">
	      To evaluate an expression, type it into the <guilabel>Console</guilabel> work area and press enter.
	      Expressions are written in a
language called GEL.  The most simple GEL expressions just looks like
mathematics.  For example
<screen lang="en"><prompt>genius&gt; </prompt><userinput>30*70 + 67^3.0 + ln(7) * (88.8/100)</userinput>
</screen>
or
<screen lang="en"><prompt>genius&gt; </prompt><userinput>62734 + 812634 + 77^4 mod 5</userinput>
</screen>
or
<screen lang="en"><prompt>genius&gt; </prompt><userinput>| sin(37) - e^7 |</userinput>
</screen>
or
<screen lang="en"><prompt>genius&gt; </prompt><userinput>sum n=1 to 70 do 1/n</userinput>
</screen>
(Last is the harmonic sum from 1 to 70)
</para>
<para lang="en">
To get a list of functions and commands, type:
<screen lang="en"><prompt>genius&gt; </prompt><userinput>help</userinput>
</screen>
If you wish to get more help on a specific function, type:
<screen lang="en"><prompt>genius&gt; </prompt><userinput>help FunctionName</userinput>
</screen>
To view this manual, type:
<screen lang="en"><prompt>genius&gt; </prompt><userinput>manual</userinput>
</screen>
</para>
<para lang="en">
Suppose you have previously saved some GEL commands as a program to a file and
you now want to execute them.
To load this program from the file <filename>path/to/program.gel</filename>,
type
<screen lang="en"><prompt>genius&gt; </prompt><userinput>load path/to/program.gel</userinput>
</screen>
<application>Genius Mathematics Tool</application> keeps track of the current directory.
To list files in the current directory type <command>ls</command>, to change directory
do <userinput>cd directory</userinput> as in the UNIX command shell.
</para>
    </sect1>

    <sect1 id="genius-usage-create-program"> 
      <title>Création d'un programme</title> 
      <para lang="en">
	      If you wish to enter several more complicated commands, or perhaps write a complicated
	      function using the <link linkend="genius-gel">GEL</link> language, you can create a new
	     program; really just a file with many commands.
      </para>
      <para lang="en">
To start writing a new program, choose
<menuchoice><guimenu>File</guimenu><guimenuitem>New
Program</guimenuitem></menuchoice>. A new tab will appear in the work area. You
can write a <link linkend="genius-gel">GEL</link> program in this work area.
Once you have written your program you can run it by 
<menuchoice><guimenu>Calculator</guimenu><guimenuitem>Run</guimenuitem></menuchoice> (or
the <guilabel>Run</guilabel> toolbar button).
This will execute your program and will display any output on the <guilabel>Console</guilabel> tab.
Executing a program is equivalent of taking the text of the program and
typing it into the console.  The only difference is that this input is done
independent of the console and just the output goes onto the console.
<menuchoice><guimenu>Calculator</guimenu><guimenuitem>Run</guimenuitem></menuchoice>
will always run the currently selected program even if you are on the <guilabel>Console</guilabel>
tab.  The currently selected program has its tab in bold type.  To select a
program, just click on its tab.
      </para>
      <para lang="en">
To save the program you've just written, choose <menuchoice><guimenu>File</guimenu><guimenuitem>Save As...</guimenuitem></menuchoice>.
Similarly as in other programs you can choose
<menuchoice><guimenu>File</guimenu><guimenuitem>Save</guimenuitem></menuchoice> to save a program that already has
a filename attached to it.  If you have many opened programs you have edited and wish to save you can also choose
<menuchoice><guimenu>File</guimenu><guimenuitem>Save All Unsaved</guimenuitem></menuchoice>.
      </para>
      <para lang="en">
	      Programs that have unsaved changes will have a "[+]" next to their filename.  This way you can see if the file
	      on disk and the currently opened tab differ in content.  Programs which have not yet had a filename associated
	      with them are always considered unsaved and no "[+]" is printed.
      </para>
    </sect1>

    <sect1 id="genius-usage-open-program"> 
      <title>Ouverture et lancement d'un programme</title> 
      <para>Pour ouvrir un fichier, choisissez <menuchoice><guimenu>Fichier</guimenu><guimenuitem>Ouvrir</guimenuitem></menuchoice>. Un nouvel onglet contenant le fichier apparaît dans la zone de travail. Vous pouvez l'utiliser pour modifier le fichier.</para>
      <para>Pour lancer un programme à partir d'un fichier, choisissez <menuchoice><guimenu>Fichier</guimenu><guimenuitem>Charger et exécuter...</guimenuitem></menuchoice>. Le programme est lancé sans être ouvert dans un onglet séparé. C'est équivalent à la commande <command>load</command>.</para>
      <para lang="en">
	      If you have made edits to a file you wish to throw away and want to reload to the version that's on disk,
	      you can choose the
	      <menuchoice><guimenu>File</guimenu><guimenuitem>Reload from Disk</guimenuitem></menuchoice> menuitem.  This is useful for experimenting
	      with a program and making temporary edits, to run a program, but that you do not intend to keep.
      </para>
    </sect1>

  </chapter>

  <!-- ============= Plotting ============================== -->
  <chapter id="genius-gel-plotting">
    <title>Tracé de graphiques</title>

    <para>Le tracé de graphiques n'est disponible que dans la version graphique GNOME. Tous les tracés accessibles à partir de l'interface graphique sont disponibles à partir de la fenêtre <guilabel>Création de graphiques</guilabel>. Vous pouvez accéder à cette fenêtre, soit en cliquant sur le bouton <guilabel>Tracer</guilabel> de la barre d'outils ou en sélectionnant <guilabel>Tracer</guilabel> dans le menu <guilabel>Calculateur</guilabel>. Vous pouvez également accéder aux fonctionnalités de tracer en utilisant les <link linkend="genius-gel-function-list-plotting">fonctions de tracé</link> du langage GEL. Consultez <xref linkend="genius-gel"/> pour apprendre comment saisir des expressions compréhensibles par Genius.</para>

    <sect1 id="genius-line-plots">
      <title>Tracé de lignes</title>
      <para lang="en">
	To graph real-valued functions of one variable, open the <guilabel>Create Plot</guilabel>
	window.  You can also use the
        <link linkend="gel-function-LinePlot"><function>LinePlot</function></link> function
	on the command line (see its documentation).  And by the words line plot, we mean plots in the plane,
	as opposed to surface plots, which are in three dimensions.
      </para>
      <para>Une fois que vous avez cliqué sur le bouton <guilabel>Tracer</guilabel>, une fenêtre contenant des onglets apparaît. Vous devez être dans l'onglet <guilabel>Tracé de lignes</guilabel> et dans celui-ci, vous devez être dans l'onglet <guilabel>Fonctions / Expressions</guilabel> (consultez <xref linkend="lineplot-fig"/>).</para>

      <figure id="lineplot-fig"> 
        <title>Fenêtre Création de graphiques</title> 
        <screenshot> 
          <mediaobject lang="en"> 
            <imageobject>
              <imagedata fileref="figures/line_plot.png" format="PNG" scalefit="1"/> 
            </imageobject>
            <textobject> 
              <phrase>Shows the line plotting window.</phrase> 
            </textobject> 
          </mediaobject> 
        </screenshot> 
      </figure>

      <para lang="en">
	Type expressions with <userinput>x</userinput> as
	the independent variable into the textboxes.  Alternatively you can give names of functions such as
	<userinput>cos</userinput> rather then having to type <userinput>cos(x)</userinput>.
	You can graph up to ten functions.  If you make a mistake and Genius cannot
	parse the input it will signify this with a warning icon on the right of the text
	input box where the error occurred, as well as giving you an error dialog.
	You can change the ranges of the dependent and independent variables in the bottom
	part of the dialog.  In the boxes for the ranges, simple expressions are allowed,
	such as <userinput>2*pi</userinput> or <userinput>10^3</userinput>.
	The <varname>y</varname> (dependent) range can be set automatically by turning on the <guilabel>Fit dependent axis</guilabel>
	checkbox.
	The names of the variables can also be changed.
	Pressing the <guilabel>Plot</guilabel> button produces the graph shown in <xref linkend="lineplot2-fig"/>.
      </para>
      <para lang="en">
	      The variables can be renamed by clicking the <guilabel>Change variable names...</guilabel> button, which is useful if you wish to print or save the figure and don't want to use the standard
	      names.  Finally you can also avoid printing the legend and the axis labels completely,
	      which is also useful if printing or
	      saving, when the legend might simply be clutter.
      </para>

      <figure id="lineplot2-fig"> 
        <title>Fenêtre contenant une courbe</title> 
        <screenshot> 
          <mediaobject lang="en"> 
            <imageobject>
              <imagedata fileref="figures/line_plot_graph.png" format="PNG" scalefit="1"/> 
            </imageobject>
            <textobject> 
              <phrase>The graph produced.</phrase> 
            </textobject> 
          </mediaobject> 
        </screenshot> 
      </figure>

      <para>À partir de là, vous pouvez imprimer le graphe, créer une version postscript encapsulé ou PNG du graphe ou modifier le zoom. Si l'axe dépendant n'a pas été configuré correctement, Genius peut l'avoir ajusté en cherchant les extrema des fonctions tracées.</para>

      <para>Pour tracer à partir de la ligne de commande, consultez la documentation de la fonction <link linkend="gel-function-LinePlot"><function>LinePlot</function></link>.</para>
    </sect1>

    <sect1 id="genius-parametric-plots">
      <title>Courbes paramétriques</title>
      <para lang="en">
	In the create plot window, you can also choose the <guilabel>Parametric</guilabel> notebook
        tab to create two dimensional parametric plots.  This way you can
	plot a single parametric function.  You can either specify the
	points as <varname>x</varname> and <varname>y</varname>, or giving a single complex number
	as a function of the variable <varname>t</varname>.
	The range of the variable <varname>t</varname> is given explicitly, and the function is sampled
	according to the given increment.
	The <varname>x</varname> and <varname>y</varname> range can be set
	automatically by turning on the <guilabel>Fit dependent axis</guilabel>
	checkbox, or it can be specified explicitly.
	See <xref linkend="paramplot-fig"/>.
      </para>

      <figure id="paramplot-fig"> 
        <title>Onglet pour les courbes paramétriques</title> 
        <screenshot> 
          <mediaobject lang="en"> 
            <imageobject>
              <imagedata fileref="figures/parametric.png" format="PNG" scalefit="1"/> 
            </imageobject>
            <textobject> 
              <phrase>Parametric plotting tab in the <guilabel>Create Plot</guilabel> window.</phrase> 
            </textobject> 
          </mediaobject> 
        </screenshot> 
      </figure>

      <para lang="en">
	An example of a parametric plot is given in
	<xref linkend="paramplot2-fig"/>.
	Similar operations can be
	done on such graphs as can be done on the other line plots.
	For plotting using the command line see the documentation of the
        <link linkend="gel-function-LinePlotParametric"><function>LinePlotParametric</function></link> or
        <link linkend="gel-function-LinePlotCParametric"><function>LinePlotCParametric</function></link> function.
      </para>

      <figure id="paramplot2-fig"> 
        <title>Courbe paramétrique</title> 
        <screenshot> 
          <mediaobject lang="en"> 
            <imageobject>
              <imagedata fileref="figures/parametric_graph.png" format="PNG" scalefit="1"/> 
            </imageobject>
            <textobject> 
              <phrase>Parametric plot produced</phrase> 
            </textobject> 
          </mediaobject> 
        </screenshot> 
      </figure>

    </sect1>

    <sect1 id="genius-slopefield-plots">
      <title>Champ de directions</title>
      <para>Dans la fenêtre de création de graphiques, vous pouvez également sélectionner l'onglet <guilabel>Champ de directions</guilabel> pour créer un graphique de champ de directions à deux dimensions. Des opérations, similaires à celles qui peuvent être réalisées sur les tracés de lignes, peuvent être réalisées sur des graphiques de ce type. Pour réaliser des graphiques en ligne de commande, consultez la documentation de la fonction <link linkend="gel-function-SlopefieldPlot"><function>SlopefieldPlot</function></link>.</para>

      <para>Quand un champ de directions est actif, un menu supplémentaire <guilabel>Solveur</guilabel> est disponible, il vous permet d'afficher la boîte de dialogue du solveur. Dans celle-ci, vous pouvez faire tracer à Genius des solutions spécifiques pour les conditions initiales fournies. Vous pouvez soit indiquer des conditions initiales spécifiques dans la boîte de dialogue ou cliquer sur le graphique directement pour indiquer le point de départ. Tant que la boîte de dialogue du solveur est active, la fonction de zoom par clic et déplacement ne fonctionne pas. Vous devez d'abord fermer la boîte de dialogue si vous voulez zoomer avec votre souris.</para>

      <para>Le solveur utilise la méthode standard de Runge-Kutta. Les graphiques restent sur l'écran jusqu'à ce qu'ils soient effacés. Le solveur s'arrête à chaque fois qu'il atteint les limites de la fenêtre du graphique. Le fait de zoomer ne modifie pas les limites ou paramètres des solutions, vous devez les effacer et les redessiner avec les paramètres appropriés. Vous pouvez utiliser la fonction <link linkend="gel-function-SlopefieldDrawSolution"><function>SlopefieldDrawSolution</function></link> pour tracer les solutions à partir de la ligne de commande ou dans des programmes.</para>

    </sect1>

    <sect1 id="genius-vectorfield-plots">
      <title>Champ de vecteurs</title>
      <para>Dans la fenêtre de création de graphiques, vous pouvez également sélectionner l'onglet <guilabel>Champ de vecteurs</guilabel> pour créer un graphique de champ de vecteurs à deux dimensions. Des opérations, similaires à celles qui peuvent être réalisées sur les tracés de lignes, peuvent être réalisées sur des graphiques de ce type. Pour réaliser des graphiques en ligne de commande, consultez la documentation de la fonction <link linkend="gel-function-VectorfieldPlot"><function>VectorfieldPlot</function></link>.</para>

      <para>Par défaut, la direction et l'amplitude du champ de vecteurs sont affichées. Pour n'afficher que la direction, cochez la case appropriée pour normaliser la longueur des flèches.</para>

      <para>Quand un champ de vecteurs est actif, un menu supplémentaire <guilabel>Solveur</guilabel> est disponible, vous permettant d'afficher la boîte de dialogue du solveur. Dans celle-ci, vous pouvez faire tracer à Genius des solutions spécifiques pour les conditions initiales fournies. Vous pouvez soit indiquer des conditions initiales spécifiques dans la boîte de dialogue ou cliquer sur le graphique directement pour indiquer le point de départ. Tant que la boîte de dialogue du solveur est active, la fonction de zoom par clic et déplacement ne fonctionne pas. Vous devez d'abord fermer la boîte de dialogue si vous voulez zoomer avec votre souris.</para>

      <para>Le solveur utilise la méthode standard de Runge-Kutta. Les graphiques restent sur l'écran jusqu'à ce qu'ils soient effacés. Le fait de zoomer ne modifie pas les limites ou paramètres des solutions, vous devez effacer et les redessiner avec les paramètres appropriés. Vous pouvez utiliser la fonction <link linkend="gel-function-VectorfieldDrawSolution"><function>VectorfieldDrawSolution</function></link> pour tracer les solutions à partir de la ligne de commande ou dans des programmes.</para>

    </sect1>

    <sect1 id="genius-surface-plots">
      <title>Tracé de surfaces</title>
      <para lang="en">
	Genius can also plot surfaces.  Select the <guilabel>Surface plot</guilabel> tab in the
	main notebook of the <guilabel>Create Plot</guilabel> window.  Here you can specify a single
	expression that should use either <varname>x</varname> and <varname>y</varname> as real independent variables
	or <varname>z</varname> as a complex variable (where <varname>x</varname> is the real part of <varname>z</varname> and <varname>y</varname> is the
	imaginary part).  For example to plot the modulus of the cosine
	function for complex parameters,
	you could enter <userinput>|cos(z)|</userinput>.  This would be
	equivalent to <userinput>|cos(x+1i*y)|</userinput>.
	See <xref linkend="surfaceplot-fig"/>.
	For plotting using the command line see the documentation of the
        <link linkend="gel-function-SurfacePlot"><function>SurfacePlot</function></link> function.
      </para>
      <para lang="en">
	      The <varname>z</varname> range can be set automatically by turning on the <guilabel>Fit dependent axis</guilabel>
	      checkbox.  The variables can be renamed by clicking the <guilabel>Change variable names...</guilabel> button, which is useful if you wish to print or save the figure and don't want to use the standard
	      names.  Finally you can also avoid printing the legend, which is also useful if printing or
	      saving, when the legend might simply be clutter.
      </para>

      <figure id="surfaceplot-fig"> 
        <title>Graphique de surface</title> 
        <screenshot> 
          <mediaobject lang="en"> 
            <imageobject>
              <imagedata fileref="figures/surface_graph.png" format="PNG" scalefit="1"/> 
            </imageobject>
            <textobject> 
              <phrase>Modulus of the complex cosine function.</phrase> 
            </textobject> 
          </mediaobject> 
        </screenshot> 
      </figure>

      <para lang="en">
	      In surface mode, left and right arrow keys on your keyboard will rotate the
	      view along the z axis.  Alternatively you can rotate along any axis by
	      selecting <guilabel>Rotate axis...</guilabel> in the <guilabel>View</guilabel> 
	      menu.  The <guilabel>View</guilabel> menu also has a top view mode which rotates the
	      graph so that the z axis is facing straight out, that is, we view the graph from the top
	      and get essentially just the colors that define the values of the function getting a
	      temperature plot of the function.  Finally you should
	      try <guilabel>Start rotate animation</guilabel>, to start a continuous slow rotation.
	      This is especially good if using <application>Genius Mathematics Tool</application> to present to an audience.
      </para>

    </sect1>

  </chapter>

  <!-- ============= GEL ====================================== -->
  <chapter id="genius-gel"> 
    <title>Fondamentaux GEL</title> 

	<para lang="en">
	  GEL stands for Genius Extension Language.  <!-- Alternatively it also
	  stands for George's Ego Leverage. -->  It is the language you use
	  to write programs in Genius. A program in GEL is simply an
	  expression that evaluates to a number, a matrix, or another object
	  in GEL.
	  <application>Genius Mathematics Tool</application> can be used as a simple calculator, or as a
	  powerful theoretical research tool.  The syntax is meant to
	  have as shallow of a learning curve as possible, especially for use
	  as a calculator.
	</para>

    <sect1 id="genius-gel-values">
      <title>Types de données</title>

      <para lang="en">
	      Values in GEL can be <link linkend="genius-gel-values-numbers">numbers</link>, <link linkend="genius-gel-values-booleans">Booleans</link>, or <link linkend="genius-gel-values-strings">strings</link>.   GEL also treats 
<link linkend="genius-gel-matrices">matrices</link> as values.
	      Values can be used in calculations, assigned to variables and returned from functions, among other uses.
      </para>

      <sect2 id="genius-gel-values-numbers">
        <title>Nombres</title>
        <para lang="en">
Integers are the first type of number in GEL. Integers are written in the normal way.
<programlisting lang="en">1234
</programlisting>
Hexadecimal and octal numbers can be written using C notation. For example:
<programlisting lang="en">0x123ABC
01234
</programlisting>
Or you can type numbers in an arbitrary base using <literal>&lt;base&gt;\&lt;number&gt;</literal>. Digits higher than 10 use letters in a similar way to hexadecimal. For example, a number in base 23 could be written:
<programlisting lang="en">23\1234ABCD
</programlisting>
        </para>

        <para lang="en">
The second type of GEL number is rationals. Rationals are simply achieved by dividing two integers. So one could write:
<programlisting lang="en">3/4
</programlisting>
to get three quarters. Rationals also accept mixed fraction notation. So in order to get one and three tenths you could write:
<programlisting lang="en">1 3/10
</programlisting>
        </para>

        <para lang="en">
The next type of number is floating point. These are entered in a similar fashion to C notation. You can use <literal>E</literal>, <literal>e</literal> or <literal>@</literal> as the exponent delimiter. Note that using the exponent delimiter gives a float even if there is no decimal point in the number. Examples:
<programlisting lang="en">1.315
7.887e77
7.887e-77
.3
0.3
77e5
</programlisting>
	When Genius prints a floating point number it will always append a
	<computeroutput>.0</computeroutput> even if the number is whole.  This is to indicate that
	floating point numbers are taken as imprecise quantities.  When a number is written in the
	scientific notation, it is always a floating point number and thus Genius does not
	print the <computeroutput>.0</computeroutput>.
        </para>

        <para lang="en">
The final type of number in GEL is the complex numbers. You can enter a complex number as a sum of real and imaginary parts. To add an imaginary part, append an <literal>i</literal>.  Here are examples of entering complex numbers:
<programlisting lang="en">1+2i
8.01i
77*e^(1.3i)
</programlisting>
        </para>

        <important>
          <para>Lorsque vous saisissez des nombres imaginaires, il doit y avoir un nombre devant le <literal>i</literal>. Si vous utilisez <literal>i</literal> tout seul, Genius l'interprète comme une référence à la variable <varname>i</varname>. Si vous avez besoin de faire référence à <literal>i</literal> tout seul, utilisez <literal>1i</literal> à la place.</para>

          <para>Afin de pouvoir utiliser la notation en fraction mixte avec des nombres imaginaires, vous devez mettre la fraction mixte entre parenthèses (par exemple, <userinput>(1 2/5)i</userinput>).</para>
        </important>

      </sect2>


      <sect2 id="genius-gel-values-booleans">
        <title>Booléens</title>
        <para>Genius prend également en charge nativement les données booléennes. Les deux constantes booléennes sont <constant>true</constant> (vrai) et <constant>false</constant> (faux) ; ces identifiants peuvent être utilisés comme n'importe quelle autre variable. Vous pouvez aussi utiliser les identifiants <constant>True</constant>, <constant>TRUE</constant>, <constant>False</constant> et <constant>FALSE</constant> comme alias de ces précédents.</para>
        <para>Là où une expression booléenne est attendue, vous pouvez utiliser une grandeur booléenne ou toute expression qui produit soit un nombre soit un booléen. Si Genius a besoin d'évaluer un nombre en tant que booléen, il interprète 0 comme <constant>false</constant> et tout autre nombre comme <constant>true</constant>.</para>
        <para lang="en">
In addition, you can do arithmetic with Boolean values. For example:
<programlisting lang="en">( (1 + true) - false ) * true
</programlisting>
is the same as:
<programlisting lang="en">( (true or true) or not false ) and true
</programlisting>
Only addition, subtraction and multiplication are supported. If you mix numbers with Booleans in an expression then the numbers are converted to Booleans as described above. This means that, for example:
<programlisting lang="en">1 == true
</programlisting>
always evaluates to <constant>true</constant> since 1 will be converted to <constant>true</constant> before being compared to <constant>true</constant>.
        </para>
      </sect2>


      <sect2 id="genius-gel-values-strings">
        <title>Chaînes de caractères</title>
        <para lang="en">
Like numbers and Booleans, strings in GEL can be stored as values inside variables and passed to functions. You can also concatenate a string with another value using the plus operator. For example:
<programlisting lang="en">a=2+3;"The result is: "+a
</programlisting>
will create the string:
<programlisting lang="en">The result is: 5
</programlisting>
You can also use C-like escape sequences such as <literal>\n</literal>,<literal>\t</literal>,<literal>\b</literal>,<literal>\a</literal> and <literal>\r</literal>. To get a <literal>\</literal> or <literal>"</literal> into the string you can quote it with a <literal>\</literal>. For example:
<programlisting lang="en">"Slash: \\ Quotes: \" Tabs: \t1\t2\t3"
</programlisting>
will make a string:
<programlisting lang="en">Slash: \ Quotes: " Tabs: 	1	2	3
</programlisting>
Do note however that when a string is returned from a function, escapes are
quoted, so that the output can be used as input.  If you wish to print the
string as it is (without escapes), use the 
<link linkend="gel-function-print"><function>print</function></link>
or
<link linkend="gel-function-printn"><function>printn</function></link> functions.
        </para>
        <para lang="en">
		In addition, you can use the library function <link linkend="gel-function-string"><function>string</function></link> to convert anything to a string. For example:
<programlisting lang="en">string(22)
</programlisting>
will return
<programlisting lang="en">"22"
</programlisting>
Strings can also be compared with <literal>==</literal> (equal), <literal>!=</literal> (not equal) and <literal>&lt;=&gt;</literal> (comparison) operators
        </para>
      </sect2>


      <sect2 id="genius-gel-values-null">
        <title>Null</title>
        <para lang="en">
There is a special value called
<constant>null</constant>. No operations can be performed on
it, and nothing is printed when it is returned. Therefore,
<constant>null</constant> is useful when you do not want output from an
expression.  The value <constant>null</constant> can be obtained as an expression when you
type <literal>.</literal>, the constant <constant>null</constant> or nothing.
By nothing we mean that if you end an expression with
a separator <literal>;</literal>, it is equivalent to ending it with a
separator followed by a <constant>null</constant>.
        </para>
        <para lang="en">
Example:
<programlisting lang="en">x=5;.
x=5;
</programlisting>
        </para>
<para>Certaines fonctions renvoient <constant>null</constant> quand aucune valeur ne peut être renvoyée ou quand une erreur survient. La grandeur <constant>null</constant> est aussi utilisée comme vecteur ou matrice vide ou comme une référence vide.</para>
      </sect2>

    </sect1>

    <sect1 id="genius-gel-variables">
      <title>Utilisation des variables</title>

      <para lang="en">
Syntax:
<programlisting lang="en">VariableName
</programlisting>
Example:
<screen lang="en"><prompt>genius&gt; </prompt><userinput>e</userinput>
= 2.71828182846
</screen>
      </para>

      <para>Pour évaluer une variable elle-même, il suffit de saisir le nom de la variable. Cela renvoie la valeur de la variable. Vous pouvez utiliser une variable n'importe où, où vous utiliseriez normalement un nombre ou une chaîne. De plus, les variables sont indispensables pour définir des fonctions qui possèdent des arguments (consultez <xref linkend="genius-gel-functions-defining"/>).</para>

      <tip>
        <title>Utilisation de la complétion à l'aide de la touche Tab</title>
        <para>Vous pouvez utiliser la complétion à l'aide de la touche Tab pour que Genius complète les noms de variable pour vous. Essayez de saisir les premières lettres du nom et appuyez sur la touche <userinput>Tab</userinput>.</para>
      </tip>

      <important>
        <title>Noms de variable sensibles à la casse</title>
        <para>Les noms de variable sont sensibles à la casse. Cela signifie que les variables appelées <varname>bonjour</varname>, <varname>BONJOUR</varname> et <varname>Bonjour</varname> sont toutes différentes.</para>
      </important>


      <sect2 id="genius-gel-variables-setting">
        <title>Attribution de variables</title>
        <para lang="en">
Syntax:
<programlisting lang="en"><![CDATA[<identifier> = <value>
<identifier> := <value>]]>
</programlisting>
Example:
<programlisting lang="en">x = 3
x := 3
</programlisting>
        </para>

        <para lang="en">
To assign a value to a variable, use the <literal>=</literal> or <literal>:=</literal> operators. These operators set the value of the variable and return the value you set, so you can do things like
<programlisting lang="en">a = b = 5
</programlisting>
This will set <varname>b</varname> to 5 and then also set <varname>a</varname> to 5.
        </para>

        <para>Les opérateurs <literal>=</literal> et <literal>:=</literal> peuvent tous les deux être utilisés pour définir des variables. La différence entre les deux est que l'opérateur <literal>:=</literal> agit toujours comme un opérateur d'attribution alors que l'opérateur <literal>=</literal> peut être interprété comme une opération de test d'égalité lorsqu'il est utilisé dans un contexte où une expression booléenne est attendue.</para>

	<para lang="en">
	  For more information about the scope of variables, that is when are what variables visible, see <xref linkend="genius-gel-variables-global"/>.
	</para>
      </sect2>

      <sect2 id="genius-gel-variables-built-in">
        <title>Variables internes</title>
        <para lang="en">
GEL has a number of built-in ‘variables’, such as
<varname>e</varname>, <varname>pi</varname> or <varname>GoldenRatio</varname>.  These are widely used constants with a preset value, and
they cannot be assigned new values.
There are a number of other built-in variables.
See <xref linkend="genius-gel-function-list-constants"/> for a full list.  Note that <varname>i</varname> is not by default
the square root of negative one (the imaginary number), and is undefined to allow its use as a counter.  If you wish to write the imaginary number you need to
use <userinput>1i</userinput>.
        </para>
      </sect2>


      <sect2 id="genius-gel-previous-result">
        <title>Variable « Résultat précédent »</title>
        <para lang="en">
The <varname>Ans</varname> and <varname>ans</varname> variables can be used to get the result of the last expression. For example, if you had performed some calculation, to add 389 to the result you could do:
<programlisting lang="en">Ans+389
</programlisting>
        </para>
      </sect2>
    </sect1>

    <sect1 id="genius-gel-functions">
      <title>Utilisation des fonctions</title>

      <para lang="en">
Syntax:
<programlisting lang="en">FunctionName(argument1, argument2, ...)
</programlisting>
Example:
<programlisting lang="en">Factorial(5)
cos(2*pi)
gcd(921,317)
</programlisting>

To evaluate a function, enter the name of the function, followed by the arguments (if any) to the function in parentheses. This will return the result of applying the function to its arguments. The number of arguments to the function is, of course, different for each function.
      </para>

      <para lang="en">
	      There are many built-in functions, such as <link linkend="gel-function-sin"><function>sin</function></link>, <link linkend="gel-function-cos"><function>cos</function></link> and <link linkend="gel-function-tan"><function>tan</function></link>. You can use the <link linkend="gel-command-help"><function>help</function></link> built-in command to get a list of available functions, or see <xref linkend="genius-gel-function-list"/> for a full listing.
      </para>

      <tip>
        <title>Utilisation de la complétion à l'aide de la touche Tab</title>
        <para>Vous pouvez utiliser la fonction de complétion à l'aide de la touche Tab pour que Genius complète les noms de fonction pour vous. Essayez de saisir les quelques premières lettres du nom et appuyez sur <userinput>Tab</userinput>.</para>
      </tip>

      <important>
        <title>Noms de fonction sensibles à la casse</title>
        <para>Les noms des fonctions sont sensibles à la casse. Cela signifie que les fonctions appelées <function>fairecela</function>, <function>FAIRECELA</function> et <function>Fairecela</function> sont toutes différentes.</para>
      </important>


      <sect2 id="genius-gel-functions-defining">
        <title>Définition de fonctions</title>
        <para lang="en">
Syntax:
<programlisting lang="en"><![CDATA[function <identifier>(<comma separated arguments>) = <function body>
<identifier> = (`() = <function body>)
]]></programlisting>
The <literal>`</literal> is the backquote character, and signifies an anonymous function. By setting it to a variable name you effectively define a function.
        </para>

        <para lang="en">
A function takes zero or more comma separated arguments, and returns the result of the function body. Defining your own functions is primarily a matter of convenience; one possible use is to have sets of functions defined in GEL files that Genius can load in order to make them available.
Example:
<programlisting lang="en">function addup(a,b,c) = a+b+c
</programlisting>
then <userinput>addup(1,4,9)</userinput> yields 14
        </para>
      </sect2>

      <sect2 id="genius-gel-functions-variable-argument-lists">
        <title>Liste d'arguments variable</title>
        <para lang="en">
If you include <literal>...</literal> after the last argument name in the function declaration, then Genius will allow any number of arguments to be passed in place of that argument. If no arguments were passed then that argument will be set to <constant>null</constant>. Otherwise, it will be a horizontal vector containing all the arguments. For example:
<programlisting lang="en">function f(a,b...) = b
</programlisting>
Then <userinput>f(1,2,3)</userinput> yields <computeroutput>[2,3]</computeroutput>, while <userinput>f(1)</userinput> yields a <constant>null</constant>.
        </para>
      </sect2>


      <sect2 id="genius-gel-functions-passing-functions">
        <title>Une fonction comme argument d'une autre fonction</title>

        <para>Dans Genius, il est possible de transmettre une fonction comme argument d'une autre fonction. Cela peut être fait en utilisant soit des « nœuds de fonction », soit des fonctions anonymes.</para>

        <para lang="en">
If you do not enter the parentheses after a function name, instead of being evaluated, the function will instead be returned as a ‘function node’. The function node can then be passed to another function.
Example:
<programlisting lang="en">function f(a,b) = a(b)+1;
function b(x) = x*x;
f(b,2)
</programlisting>
        </para>
        <para lang="en">
To pass functions that are not defined,
you can use an anonymous function (see <xref linkend="genius-gel-functions-defining"/>).  That is, you want to pass a function without giving it a name.
Syntax:
<programlisting lang="en"><![CDATA[function(<comma separated arguments>) = <function body>
`(<comma separated arguments>) = <function body>
]]></programlisting>
Example:
<programlisting lang="en">function f(a,b) = a(b)+1;
f(`(x) = x*x,2)
</programlisting>
This will return 5.
        </para>
      </sect2>


    <sect2 id="genius-gel-functions-operations">
      <title>Opérations sur les fonctions</title>
      <para lang="en">
	      Some functions allow arithmetic operations, and some single argument functions such as <link linkend="gel-function-exp"><function>exp</function></link> or <link linkend="gel-function-ln"><function>ln</function></link>, to operate on the function. For example,
<programlisting lang="en">exp(sin*cos+4)
</programlisting>
will return a function that takes <varname>x</varname> and returns <userinput>exp(sin(x)*cos(x)+4)</userinput>.  It is functionally equivalent
to typing
<programlisting lang="en">`(x) = exp(sin(x)*cos(x)+4)
</programlisting>

This operation can be useful when quickly defining functions. For example to create a function called <varname>f</varname>
to perform the above operation, you can just type:
<programlisting lang="en">f = exp(sin*cos+4)
</programlisting>
It can also be used in plotting. For example, to plot sin squared you can enter:
<programlisting lang="en">LinePlot(sin^2)
</programlisting>
      </para>

      <warning>
        <para>Toutes les fonctions ne peuvent pas être utilisées de cette façon. Par exemple, lorsque vous utilisez une opération binaire, les fonctions doivent prendre le même nombre d'arguments.</para>
      </warning>
    </sect2>


    </sect1>

    <sect1 id="genius-gel-separator">
      <title>Séparateur</title>
      <para lang="en">
	      GEL is somewhat different from other languages in how it deals with multiple commands and functions.
	      In GEL you must chain commands together with a separator operator.
That is, if you want to type more than one expression you have to use
the <literal>;</literal> operator in between the expressions.   This is
a way in which both expressions are evaluated and the result of the second one (or the last one
if there is more than two expressions) is returned.
Suppose you type the following:
<programlisting lang="en">3 ; 5
</programlisting>
This expression will yield 5.
      </para>
      <para lang="en">
This will require some parenthesizing to make it unambiguous sometimes,
especially if the <literal>;</literal> is not the top most primitive. This slightly differs from
other programming languages where the <literal>;</literal> is a terminator of statements, whereas
in GEL it’s actually a binary operator. If you are familiar with pascal
this should be second nature. However genius can let you pretend it is a
terminator to some degree.  If a <literal>;</literal> is found at the end of a parenthesis or a block,
genius will append a null to it as if you would have written
<userinput>;null</userinput>.
This is useful in case you do not want to return a value from a loop,
or if you handle the return differently.
      </para>
      <para lang="en">
	      If you are typing expressions in a program file you do not have to add a semicolon.  In this case
	      genius will simply print the return value whenever it executes the expression.  This is the same
	      as when typing on the command line.  However, do note that if you are defining a
	      function, the body of the function is a single expression.  Usually, therefore, if a function body is
	      long, you will need to enclose it in parentheses.
      </para>
    </sect1>

    <sect1 id="genius-gel-comments">
      <title>Commentaires</title>
      <para lang="en">
	      GEL is similar to other scripting languages in that <literal>#</literal> denotes
	      a comment, that is text that is not meant to be evaluated.  Everything beyond the
	      pound sign till the end of line will just be ignored.  For example,
<programlisting lang="en"># This is just a comment
# every line in a comment must have its own pound sign
# in the next line we set x to the value 123
x=123;
</programlisting>
      </para>
    </sect1>

    <sect1 id="genius-gel-modular-evaluation">
      <title>Évaluation modulaire</title>
      <para lang="en">
	      Genius implements modular arithmetic.
To use it you just add "mod &lt;integer&gt;" after
the expression.  Example:
<userinput>2^(5!) * 3^(6!) mod 5</userinput>
It could be possible to do modular arithmetic by computing with integers and then modding in the end with
the <literal>%</literal> operator, which simply gives the remainder, but
that may be time consuming if not impossible when working with larger numbers.
For example, <userinput>10^(10^10) % 6</userinput> will simply not work (the exponent
will be too large), while
<userinput>10^(10^10) mod 6</userinput> is instantaneous.  The first expression first tries to compute the integer
<userinput>10^(10^10)</userinput> and then find remainder after division by 6, while the second expression evaluates
everything modulo 6 to begin with.
      </para>
      <para lang="en">
	      The inverses of numbers mod some integer are computed by writing them as
rational numbers (as long as the desired inverse exists, of course).
Examples:
<programlisting lang="en">10^-1 mod 101
1/10 mod 101</programlisting>
Modular evaluation also works with matrices including taking inverses,
powers, and dividing.
Example:
<programlisting lang="en">A = [1,2;3,4]
B = A^-1 mod 5
A*B mod 5</programlisting>
This should yield the identity matrix as B will be the inverse of A mod 5.
      </para>
      <para lang="en">
Some functions such as
<link linkend="gel-function-sqrt"><function>sqrt</function></link> or
<link linkend="gel-function-log"><function>log</function></link>
work in a different way when in modulo mode.  These will then work like their
discrete versions working within the ring of integers you selected.  For
example:
<programlisting lang="en">genius&gt; sqrt(4) mod 7
=
[2, 5]
genius&gt; 2*2 mod 7
= 4</programlisting>
	<function>sqrt</function> will actually return all the possible square
	roots.
      </para>
      <para lang="en">
	      Do not chain mod operators, simply place it at the end of the computation, all computations in the expression on the left
	      will be carried out in mod arithmetic.  If you place a mod inside
	      a mod, you will get unexpected results.  If you simply want to
	      mod a single number and control exactly when remainders are
	      taken, best to use the <literal>%</literal> operator.  When you
	      need to chain several expressions in modular arithmetic with
	      different divisors, it may be best to just split up the expression into several and use
	      temporary variables to avoid a mod inside a mod.
      </para>
    </sect1>

    <sect1 id="genius-gel-operator-list">
      <title>Liste des opérateurs GEL</title>

      <para lang="en">
	      Everything in GEL is really just an expression.  Expressions are stringed together with
	      different operators.  As we have seen, even the separator is simply a binary operator
	      in GEL.  Here is a list of the operators in GEL. 
      </para>

      <variablelist>
        <varlistentry>
         <term lang="en"><userinput>a;b</userinput></term>
         <listitem>
           <para>C'est le séparateur, il évalue simplement à la fois <varname>a</varname> et <varname>b</varname> mais ne renvoie que le résultat de <varname>b</varname>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a=b</userinput></term>
         <listitem>
           <para>L'opérateur d'attribution. Il attribue <varname>b</varname> à <varname>a</varname> (<varname>a</varname> doit être une <link linkend="genius-gel-lvalues">valeur à gauche</link> valide). Remarquez que cet opérateur peut être transformé en <literal>==</literal> s'il est utilisé là où une expression booléenne est attendue.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a:=b</userinput></term>
         <listitem>
           <para>L'opérateur d'attribution. Il attribue <varname>b</varname> à <varname>a</varname> (<varname>a</varname> doit être une <link linkend="genius-gel-lvalues">valeur à gauche</link> valide). Il est différent de <literal>=</literal> car il n'est jamais transformée en <literal>==</literal>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>|a|</userinput></term>
         <listitem>
           <para lang="en">
		   Absolute value.
		   In case the expression is a complex number the result will be the modulus
(distance from the origin).  For example:
<userinput>|3 * e^(1i*pi)|</userinput>
returns 3.
	  </para>
          <para>Consultez <ulink url="http://mathworld.wolfram.com/AbsoluteValue.html">Mathworld</ulink> pour plus d'informations.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a^b</userinput></term>
         <listitem>
           <para>Exposant, met <varname>a</varname> à la puissance <varname>b</varname>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a.^b</userinput></term>
         <listitem>
           <para>Exposant élément par élément. Met chaque élément d'une matrice <varname>a</varname> à la puissance <varname>b</varname>. Si <varname>b</varname> est une matrice de la même taille que <varname>a</varname> alors l'opération se réalise élément par élément. Si <varname>a</varname> est un nombre et <varname>b</varname> est une matrice alors cela crée une matrice de la même taille que <varname>b</varname> contenant <varname>a</varname> mis à la puissance de chaque élément de <varname>b</varname>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a+b</userinput></term>
         <listitem>
           <para lang="en">
             Addition.  Adds two numbers, matrices, functions or strings.  If
	     you add a string to anything the result will just be a string.  If one is
	     a square matrix and the other a number, then the number is multiplied by
	     the identity matrix.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a-b</userinput></term>
         <listitem>
           <para>Soustraction. Soustrait deux nombres, matrices ou fonctions.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a*b</userinput></term>
         <listitem>
           <para>Multiplication. C'est la multiplication matricielle normale.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a.*b</userinput></term>
         <listitem>
           <para>Multiplication élément par élément si <varname>a</varname> et <varname>b</varname> sont des matrices.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a/b</userinput></term>
         <listitem>
           <para lang="en">
		   Division.  When <varname>a</varname> and <varname>b</varname> are just numbers
		   this is the normal division.  When they are matrices, then this is
		   equivalent to <userinput>a*b^-1</userinput>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a./b</userinput></term>
         <listitem>
           <para lang="en">
		   Element by element division.  Same as <userinput>a/b</userinput> for
		   numbers, but operates element by element on matrices.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a\b</userinput></term>
         <listitem>
           <para>Division arrière. C'est donc la même chose que <userinput>b/a</userinput>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a.\b</userinput></term>
         <listitem>
           <para>Division arrière élément par élément.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a%b</userinput></term>
         <listitem>
           <para lang="en">
	     The mod operator.  This does not turn on the <link linkend="genius-gel-modular-evaluation">modular mode</link>, but
             just returns the remainder of integer division
             <userinput>a/b</userinput>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a.%b</userinput></term>
         <listitem>
           <para lang="en">
             Element by element mod operator.  Returns the remainder
	     after element by element integer division
	     <userinput>a./b</userinput>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a mod b</userinput></term>
         <listitem>
           <para>Opérateur d'évaluation modulaire. L'expression <varname>a</varname> est évaluée modulo <varname>b</varname>. Consultez <xref linkend="genius-gel-modular-evaluation"/>. Certaines fonctions et opérateurs se comportent différemment modulo un entier.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a!</userinput></term>
         <listitem>
           <para>Opérateur factoriel. Il s'agit de <userinput>1*...*(n-2)*(n-1)*n</userinput>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a!!</userinput></term>
         <listitem>
           <para>Opérateur double factoriel. Il s'agit de <userinput>1*...*(n-4)*(n-2)*n</userinput>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a==b</userinput></term>
         <listitem>
           <para lang="en">
	     Equality operator.
	     Returns <constant>true</constant> or <constant>false</constant>
	     depending on <varname>a</varname> and <varname>b</varname> being equal or not.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a!=b</userinput></term>
         <listitem>
           <para>Opérateur inégalité, renvoie <constant>true</constant> si <varname>a</varname> n'est pas égal à <varname>b</varname> sinon renvoie <constant>false</constant>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a&lt;&gt;b</userinput></term>
         <listitem>
           <para>Autre opérateur inégalité, renvoie <constant>true</constant> si <varname>a</varname> n'est pas égal à <varname>b</varname> sinon renvoie <constant>false</constant>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a&lt;=b</userinput></term>
         <listitem>
           <para lang="en">
             Less than or equal operator,
	     returns <constant>true</constant> if <varname>a</varname> is
	     less than or equal to 
	     <varname>b</varname> else returns <constant>false</constant>.
	     These can be chained as in <userinput>a &lt;= b &lt;= c</userinput> (can
	     also be combined with the less than operator).
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a&gt;=b</userinput></term>
         <listitem>
           <para lang="en">
             Greater than or equal operator,
	     returns <constant>true</constant> if <varname>a</varname> is
	     greater than or equal to 
	     <varname>b</varname> else returns <constant>false</constant>.
	     These can be chained as in <userinput>a &gt;= b &gt;= c</userinput>
	     (and they can also be combined with the greater than operator).
           </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><userinput>a&lt;b</userinput></term>
         <listitem>
           <para lang="en">
             Less than operator,
	     returns <constant>true</constant> if <varname>a</varname> is
	     less than 
	     <varname>b</varname> else returns <constant>false</constant>.
	     These can be chained as in <userinput>a &lt; b &lt; c</userinput>
	     (they can also be combined with the less than or equal to operator).
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a&gt;b</userinput></term>
         <listitem>
           <para lang="en">
             Greater than operator,
	     returns <constant>true</constant> if <varname>a</varname> is
	     greater than 
	     <varname>b</varname> else returns <constant>false</constant>.
	     These can be chained as in <userinput>a &gt; b &gt; c</userinput>
	     (they can also be combined with the greater than or equal to operator).
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a&lt;=&gt;b</userinput></term>
         <listitem>
           <para>Opérateur comparaison. Si <varname>a</varname> est égal à <varname>b</varname>, cela renvoie 0, si <varname>a</varname> est inférieur à <varname>b</varname>, cela renvoie -1 et si <varname>a </varname> est supérieur à <varname>b</varname>, cela renvoie 1.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a and b</userinput></term>
         <listitem>
           <para lang="en">
		   Logical and.  Returns true if both
		   <varname>a</varname> and <varname>b</varname> are true,
		   else returns false.  If given numbers, nonzero numbers
		   are treated as true.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a or b</userinput></term>
         <listitem>
           <para lang="en">
             Logical or.
	     Returns true if either
	     <varname>a</varname> or <varname>b</varname> is true,
	     else returns false.  If given numbers, nonzero numbers
	     are treated as true.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a xor b</userinput></term>
         <listitem>
           <para lang="en">
             Logical xor.
	     Returns true if exactly one of
	     <varname>a</varname> or <varname>b</varname> is true,
	     else returns false.  If given numbers, nonzero numbers
	     are treated as true.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>not a</userinput></term>
         <listitem>
           <para lang="en">
		   Logical not.  Returns the logical negation of <varname>a</varname>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>-a</userinput></term>
         <listitem>
           <para lang="en">
             Negation operator.  Returns the negative of a number or a matrix (works element-wise on a matrix).
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>&amp;a</userinput></term>
         <listitem>
           <para lang="en">
             Variable referencing (to pass a reference to a variable).
	     See <xref linkend="genius-gel-references"/>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>*a</userinput></term>
         <listitem>
           <para lang="en">
             Variable dereferencing (to access a referenced variable).
	     See <xref linkend="genius-gel-references"/>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a'</userinput></term>
         <listitem>
           <para lang="en">
		   Matrix conjugate transpose.  That is, rows and columns get swapped and we take complex conjugate of all entries.  That is
		   if the i,j element of <varname>a</varname> is x+iy, then the j,i element of <userinput>a'</userinput> is x-iy.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a.'</userinput></term>
         <listitem>
           <para lang="en">
             Matrix transpose, does not conjugate the entries.  That is, 
	     the i,j element of <varname>a</varname>  becomes the j,i element of <userinput>a.'</userinput>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a@(b,c)</userinput></term>
         <listitem>
           <para lang="en">
	     Get element of a matrix in row <varname>b</varname> and column
	     <varname>c</varname>.   If <varname>b</varname>,
	     <varname>c</varname> are vectors, then this gets the corresponding
	     rows, columns or submatrices.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a@(b,)</userinput></term>
         <listitem>
           <para>Renvoie une ligne de matrice (ou plusieurs lignes si <varname>b</varname> est un vecteur).</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a@(b,:)</userinput></term>
         <listitem>
           <para>Comme ci-dessus.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a@(,c)</userinput></term>
         <listitem>
           <para>Renvoie une colonne de matrice (ou des colonnes si <varname>c</varname> est un vecteur).</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a@(:,c)</userinput></term>
         <listitem>
           <para>Comme ci-dessus.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a@(b)</userinput></term>
         <listitem>
           <para>Renvoie un élément d'une matrice en le traitant comme un vecteur. Cela parcourt la matrice dans le sens des lignes.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a:b</userinput></term>
         <listitem>
           <para lang="en">
             Build a vector from <varname>a</varname> to <varname>b</varname> (or specify a row, column region for the <literal>@</literal> operator).  For example to get rows 2 to 4 of matrix <varname>A</varname> we could do
	     <programlisting lang="en">A@(2:4,)
	     </programlisting>
	     as <userinput>2:4</userinput> will return a vector
	     <userinput>[2,3,4]</userinput>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>a:b:c</userinput></term>
         <listitem>
           <para lang="en">
	     Build a vector from <varname>a</varname> to <varname>c</varname>
	     with <varname>b</varname> as a step.  That is for example
	     <programlisting lang="en">genius&gt; 1:2:9
=
`[1, 3, 5, 7, 9]
</programlisting>
           </para>
	   <para lang="en">
	     When the numbers involved are floating point numbers, for example
	     <userinput>1.0:0.4:3.0</userinput>, the output is what is expected
	     even though adding 0.4 to 1.0 five times is actually just slightly
	     more than 3.0 due to the way that floating point numbers are
	     stored in base 2 (there is no 0.4, the actual number stored is
	     just ever so slightly bigger).  The way this is handled is the
	     same as in the for, sum, and prod loops.  If the end is within
	     <userinput>2^-20</userinput> times the step size of the endpoint,
	     the endpoint is used and we assume there were roundoff errors.
	     This is not perfect, but it handles the majority of the cases.
	     This check is done only from version 1.0.18 onwards, so execution
	     of your code may differ on older versions.  If you want to avoid
	     dealing with this issue, use actual rational numbers, possibly
	     using the <function>float</function> if you wish to get floating
	     point numbers in the end.  For example
	     <userinput>1:2/5:3</userinput> does the right thing and
	     <userinput>float(1:2/5:3)</userinput> even gives you floating
	     point numbers and is ever so slightly more precise than
	     <userinput>1.0:0.4:3.0</userinput>.
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>(a)i</userinput></term>
         <listitem>
           <para lang="en">
	     Make <varname>a</varname> into an imaginary number (multiply <varname>a</varname> by the
	     imaginary).  Normally the imaginary number <varname>i</varname> is
	     written as <userinput>1i</userinput>.  So the above is equal to
	     <programlisting lang="en">(a)*1i
	     </programlisting>
           </para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><userinput>`a</userinput></term>
         <listitem>
           <para>Apostropher un identifiant afin qu'il ne soit pas évalué. Ou apostropher une matrice afin qu'elle ne soit pas étendue.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><userinput>a swapwith b</userinput></term>
         <listitem>
           <para>Échange la valeur de <varname>a</varname> par la valeur de <varname>b</varname>. Pour le moment, ne fonctionne pas sur des ensembles d'éléments de matrice. Renvoie <constant>null</constant>. Disponible à partir de la version 1.0.13.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><userinput>increment a</userinput></term>
         <listitem>
           <para>Incrémente la variable <varname>a</varname> de 1. Si <varname>a</varname> est une matrice alors incrémente chaque élément. C'est équivalent à <userinput>a=a+1</userinput> mais est plus rapide. Renvoie <constant>null</constant>. Disponible à partir de la version 1.0.13.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><userinput>increment a by b</userinput></term>
         <listitem>
           <para>Incrémente la variable <varname>a</varname> de <varname>b</varname>. Si <varname>a</varname> est une matrice alors incrémente chaque élément. C'est équivalent à <userinput>a=a+b</userinput> mais est plus rapide. Renvoie <constant>null</constant>. Disponible à partir de la version 1.0.13.</para>
         </listitem>
        </varlistentry>


      </variablelist>

<note>
<para>L'opérateur @() rend l'opérateur : très utile. Grâce à lui, vous pouvez indiquer des régions d'une matrice. Ainsi a@(2:4,6) sont les lignes 2,3,4 de la colonne 6 ou a@(,1:2) vous renvoie les deux premières colonnes d'une matrice. Vous pouvez également attribuer un opérateur @() tant que la valeur de droite est une matrice qui correspond en taille à la région ou si c'est n'importe quel autre type de valeur.</para>
</note>

<note>
<para lang="en">
The comparison operators (except for the &lt;=&gt; operator, which behaves normally), are not strictly binary operators, they can in fact be grouped in the normal mathematical way, e.g.: (1&lt;x&lt;=y&lt;5) is a legal boolean expression and means just what it should, that is (1&lt;x and x≤y and y&lt;5)
</para>
</note>

<note>
<para>L'opérateur unitaire « moins » agit de manière différente en fonction de l'endroit où il apparaît. S'il apparaît devant un nombre, il est très prioritaire, s'il apparaît devant une expression, il est moins prioritaire que les opérateurs puissance et factoriel. Par exemple, <userinput>-1^k</userinput> est bien <userinput>(-1)^k</userinput>, mais <userinput>-foo(1)^k</userinput> est bien <userinput>-(foo(1)^k)</userinput>. En conséquence, faites attention à son utilisation et, en cas de doute, ajoutez des parenthèses.</para>
</note>
    </sect1>

  </chapter>

  <!-- ============= GEL Programming ========================== -->
  <chapter id="genius-gel-programming">
    <title>Programmation avec GEL</title>

    <sect1 id="genius-gel-conditionals">
      <title>Tests</title>
      <para lang="en">
Syntax:
<programlisting lang="en"><![CDATA[if <expression1> then <expression2> [else <expression3>]
]]></programlisting>
If <literal>else</literal> is omitted, then if the <literal>expression1</literal> yields <constant>false</constant> or 0, <literal>NULL</literal> is returned.
      </para>
      <para lang="en">
Examples:
<programlisting lang="en"><![CDATA[if(a==5)then(a=a-1)
if b<a then b=a
if c>0 then c=c-1 else c=0
a = ( if b>0 then b else 1 )
]]></programlisting>
Note that <literal>=</literal> will be translated to <literal>==</literal> if used inside the expression for <literal>if</literal>, so
<programlisting lang="en">if a=5 then a=a-1
</programlisting>
will be interpreted as:
<programlisting lang="en">if a==5 then a:=a-1
</programlisting>
      </para>
    </sect1>

    <sect1 id="genius-gel-loops">
      <title>Boucles</title>

      <sect2 id="genius-gel-loops-while">
        <title>Boucles tant que (while) et jusqu'à (until)</title>
        <para lang="en">
Syntax:
<programlisting lang="en"><![CDATA[while <expression1> do <expression2>
until <expression1> do <expression2>
do <expression2> while <expression1>
do <expression2> until <expression1>]]></programlisting>

	These are similar to other languages.  However, as in GEL it is simply an expression that must have some return value, these
	constructs will simply return the result of the last iteration or <literal>NULL</literal> if no iteration was done.  In the boolean expression, <literal>=</literal> is translated into <literal>==</literal> just as for the <literal>if</literal> statement.
        </para>
      </sect2>

      <sect2 id="genius-gel-loops-for">
        <title>Boucles pour (for)</title>
        <para lang="en">
Syntax:
<programlisting lang="en"><![CDATA[for <identifier> = <from> to <to> do <body>
for <identifier> = <from> to <to> by <increment> do <body>]]></programlisting>

Loop with identifier being set to all values from <literal>&lt;from&gt;</literal> to <literal>&lt;to&gt;</literal>, optionally using an increment other than 1. These are faster, nicer and more compact than the normal loops such as above, but less flexible. The identifier must be an identifier and can't be a dereference. The value of identifier is the last value of identifier, or <literal>&lt;from&gt;</literal> if body was never evaluated. The variable is guaranteed to be initialized after a loop, so you can safely use it.  Also the <literal>&lt;from&gt;</literal>, <literal>&lt;to&gt;</literal> and <literal>&lt;increment&gt;</literal> must be non complex values. The <literal>&lt;to&gt;</literal> is not guaranteed to be hit, but will never be overshot, for example the following prints out odd numbers from 1 to 19:
<programlisting lang="en">for i = 1 to 20 by 2 do print(i)
</programlisting>
        </para>
        <para lang="en">
		When one of the values is a floating point number, then the
		final check is done to within 2^-20 of the step size.  That is,
		even if we overshoot by 2^-20 times the "by" above, we still execute the last
		iteration.  This way 
<programlisting lang="en">for x = 0 to 1 by 0.1 do print(x)
</programlisting>
does the expected even though adding 0.1 ten times becomes just slightly more than 1.0 due to the way that floating point numbers
are stored in base 2 (there is no 0.1, the actual number stored is just ever so slightly bigger).  This is not perfect but it handles
the majority of the cases.  If you want to avoid dealing with this issue, use actual rational numbers for example:
<programlisting lang="en">for x = 0 to 1 by 1/10 do print(x)
</programlisting>
		This check is done only from version 1.0.16 onwards, so execution of your code may differ on older versions.
	</para>
      </sect2>

      <sect2 id="genius-gel-loops-foreach">
        <title>Boucles pour chaque (foreach)</title>
        <para lang="en">
Syntax:
<programlisting lang="en"><![CDATA[for <identifier> in <matrix> do <body>]]></programlisting>

			For each element in the matrix, going row by row from left to right we execute the body
		       with the identifier set to the current element. To
print numbers 1,2,3 and 4 in this order you could do:
<programlisting lang="en">for n in [1,2:3,4] do print(n)
</programlisting>
If you wish to run through the rows and columns of a matrix, you can use
the RowsOf and ColumnsOf functions, which return a vector of the rows or
columns of the matrix.  So,
<programlisting lang="en">for n in RowsOf ([1,2:3,4]) do print(n)
</programlisting>
will print out [1,2] and then [3,4].
        </para>
      </sect2>

      <sect2 id="genius-gel-loops-break-continue">
        <title>Instructions « break » et « continue »</title>
        <para lang="en">
You can also use the <literal>break</literal> and <literal>continue</literal> commands in loops. The continue <literal>continue</literal> command will restart the current loop at its next iteration, while the <literal>break</literal> command exits the current loop.
<programlisting lang="en"><![CDATA[while(<expression1>) do (
  if(<expression2>) break
  else if(<expression3>) continue;
  <expression4>
)
]]></programlisting>
        </para>
      </sect2>
    </sect1>

    <sect1 id="genius-gel-sums-products">
      <title>Sommes et produits</title>
      <para lang="en">
Syntax:
<programlisting lang="en"><![CDATA[sum <identifier> = <from> to <to> do <body>
sum <identifier> = <from> to <to> by <increment> do <body>
sum <identifier> in <matrix> do <body>
prod <identifier> = <from> to <to> do <body>
prod <identifier> = <from> to <to> by <increment> do <body>
prod <identifier> in <matrix> do <body>]]></programlisting>

If you substitute <literal>for</literal> with <literal>sum</literal> or <literal>prod</literal>, then you will get a sum or a product instead of a <literal>for</literal> loop. Instead of returning the last value, these will return the sum or the product of the values respectively.
      </para>
      <para>Si aucun contenu (body) est exécuté (par exemple, <userinput>sum i=1 to 0 do ...</userinput>) alors la convention standard est que <literal>sum</literal> renvoie 0 et <literal>prod</literal> renvoie 1.</para>
      <para lang="en">
	      For floating point numbers the same roundoff error protection is done as in the for loop.
	     See <xref linkend="genius-gel-loops-for"/>.
      </para>
    </sect1>

    <sect1 id="genius-gel-comparison-operators">
      <title>Opérateurs de comparaison</title>
      <para>Les opérateurs de comparaison standard suivants sont pris en charge dans GEL et ont des significations évidentes : <literal>==</literal>, <literal>&gt;=</literal>, <literal>&lt;=</literal>, <literal>!=</literal>, <literal>&lt;&gt;</literal>, <literal>&lt;</literal>, <literal>&gt;</literal>. Ils renvoient <constant>true</constant> ou <constant>false</constant>. Les opérateurs <literal>!=</literal> et <literal>&lt;&gt;</literal> sont les mêmes et signifient « n'est pas égal à ». GEL comprend également l'opérateur <literal>&lt;=&gt;</literal> qui renvoie -1 si la partie de gauche est plus petite, 0 si les deux parties sont égales, 1 si la partie de gauche est plus grande.</para>

      <para lang="en">
	Normally <literal>=</literal> is translated to <literal>==</literal> if
	it happens to be somewhere where GEL is expecting a condition such as
	in the if condition.  For example
	<programlisting lang="en">if a=b then c
if a==b then c
</programlisting>
	are the same thing in GEL.  However you should really use
	<literal>==</literal> or <literal>:=</literal> when you want to compare
	or assign respectively if you want your code to be easy to read and
	to avoid mistakes.
      </para>

      <para lang="en">
	All the comparison operators (except for the
	<literal>&lt;=&gt;</literal> operator, which
	behaves normally), are not strictly binary operators, they can in fact
	be grouped in the normal mathematical way, e.g.:
	(<literal>1&lt;x&lt;=y&lt;5</literal>) is
	a legal boolean expression and means just what it should, that is
	(1&lt;x and x≤y and y&lt;5)
      </para>
      <para>Pour construire des expressions logiques, utilisez les mots <literal>not</literal>, <literal>and</literal>, <literal>or</literal>, <literal>xor</literal>. Les opérateurs <literal>or</literal> et <literal>and</literal> sont des entités spéciales car ils évaluent leurs arguments les uns après les autres, donc les astuces classiques des évaluations conditionnelles fonctionnent. Par exemple : <literal>1 or a=1</literal> n'effectue pas l'attribution <literal>a=1</literal> puisque le premier argument est vrai (true).</para>
    </sect1>

      <sect1 id="genius-gel-variables-global">
        <title>Variables globales et portée des variables</title>
	<para lang="en">
	  GEL is a
	  <ulink url="https://en.wikipedia.org/wiki/Scope_%28programming%29">
	  dynamically scoped language</ulink>.  We will explain what this
	  means below.  That is, normal variables and functions are dynamically
	  scoped.  The exception are 
	  <link linkend="genius-gel-parameters">parameter variables</link>,
	  which are always global.
	</para>
	<para lang="en">
	  Like most programming languages, GEL has different types
	  of variables.  Normally when a variable is defined in a function,
	  it is visible from that function and from all functions that are
	  called (all higher contexts).  For example, suppose a function
	  <function>f</function> defines a variable <varname>a</varname>
	  and then calls function <function>g</function>.  Then
	  function <function>g</function> can reference
	  <varname>a</varname>.  But once <function>f</function> returns,
	  the variable <varname>a</varname> goes out of scope.
	  For example, the following code will print out 5.
	  The function <function>g</function> cannot be called on the
	  top level (outside <function>f</function> as <varname>a</varname>
	  will not be defined).
<programlisting lang="en">function f() = (a:=5; g());
function g() = print(a);
f();
</programlisting>
        </para>
        <para lang="en">
	  If you define a variable inside a function it will override
	  any variables defined in calling functions.  For example,
	  we modify the above code and write:
<programlisting lang="en">function f() = (a:=5; g());
function g() = print(a);
a:=10;
f();
</programlisting>
	  This code will still print out 5.  But if you call
	  <function>g</function> outside of <function>f</function> then
	  you will get a printout of 10.  Note that
	  setting <varname>a</varname>
	  to 5 inside <function>f</function> does not change
	  the value of <varname>a</varname> at the top (global) level,
	  so if you now check the value of <varname>a</varname> it will
	  still be 10.
        </para>
	<para>Les arguments de fonction sont exactement comme les variables définies à l'intérieur de la fonction sauf qu'ils sont initialisés à la valeur qui a été transmise à la fonction. En dehors de ce point, ils sont traités exactement comme toutes les autres variables définies dans la fonction.</para>
	<para lang="en">
	  Functions are treated exactly like variables.  Hence you can
	  locally redefine functions.  Normally (on the top level) you
	  cannot redefine protected variables and functions.  But locally
	  you can do this.  Consider the following session:
<screen lang="en"><prompt>genius&gt; </prompt><userinput>function f(x) = sin(x)^2</userinput>
= (`(x)=(sin(x)^2))
<prompt>genius&gt; </prompt><userinput>function f(x) = sin(x)^2</userinput>
= (`(x)=(sin(x)^2))
<prompt>genius&gt; </prompt><userinput>function g(x) = ((function sin(x)=x^10);f(x))</userinput>
= (`(x)=((sin:=(`(x)=(x^10)));f(x)))
<prompt>genius&gt; </prompt><userinput>g(10)</userinput>
= 1e20
</screen>
	</para>
	<para lang="en">
	  Functions and variables defined at the top level are
	  considered global.  They are visible from anywhere.  As we
	  said the following function <function>f</function>
	  will not change the value of <varname>a</varname> to 5.
<programlisting lang="en">a=6;
function f() = (a:=5);
f();
</programlisting>
	  Sometimes, however, it is necessary to set
a global variable from inside a function.  When this behavior is needed,
use the
<link linkend="gel-function-set"><function>set</function></link> function. Passing a string or a quoted identifier to
this function sets the variable globally (on the top level).
For example, to set
<varname>a</varname> to the value 3 you could call:
<programlisting lang="en">set(`a,3)
</programlisting>
or:
<programlisting lang="en">set("a",3)
</programlisting>
        </para>
        <para>La fonction <function>set</function> définit toujours au niveau global supérieur. Il n'est pas possible de définir une variable locale dans des fonctions à partir d'un sous-programme. Si c'est nécessaire, vous devez utiliser la transmission par référence.</para>
	<para lang="en">
		See also the
		<link linkend="gel-function-SetElement"><function>SetElement</function></link> and
		<link linkend="gel-function-SetVElement"><function>SetVElement</function></link> functions.
	</para>
	<para>Donc pour récapituler dans un langage plus technique : genius opère avec différents contextes numérotés. Le niveau supérieur est le contexte 0 (zéro). À chaque fois qu'une fonction est entrée, le contexte est augmenté et lorsqu'une fonction est quittée, le contexte est diminué. Une fonction ou une variable est toujours visible à partir de tous les contextes de numéro plus élevé. Si une variable a été définie dans un contexte de numéro plus bas alors attribuer une valeur à cette variable a pour effet de créer une nouvelle variable locale dans le numéro de contexte actuel et cette variable est maintenant visible de tous les contextes de numéro plus élevé.</para>
	<para lang="en">
	  There are also true local variables that are not seen from
	  anywhere but the current context.  Also when returning functions
	  by value it may reference variables not visible from higher context
	  and this may be a problem.  See the sections
	  <link linkend="genius-gel-true-local-variables">True
	  Local Variables</link> and
	  <link linkend="genius-gel-returning-functions">Returning
	  Functions</link>.
	</para>
      </sect1>

      <sect1 id="genius-gel-parameters">
        <title>Variables paramètres</title>
	<para lang="en">
	  As we said before, there exist special variables called parameters
	  that exist in all scopes.  To declare a parameter called
	  <varname>foo</varname> with the initial value 1, we write
<programlisting lang="en"><![CDATA[parameter foo = 1
]]></programlisting>
	  From then on, <varname>foo</varname> is a strictly global variable.
	  Setting <varname>foo</varname> inside any function will modify the
	  variable in all contexts, that is, functions do not have a private
	  copy of parameters.
        </para>
        <para lang="en">
	  When you undefine a parameter using the
	  <link linkend="gel-function-undefine">
	  <function>undefine</function></link> function, it stops being
	  a parameter.
        </para>
        <para lang="en">
	  Some parameters are built-in and modify the behavior of genius.
        </para>
      </sect1>

    <sect1 id="genius-gel-returning">
      <title>Sortie de fonction</title>
	<para>Normalement une fonction est une ou plusieurs expressions séparées par un point virgule et la valeur de la dernière expression est renvoyée. C'est suffisant pour les fonctions simples mais parfois vous ne voulez pas qu'une fonction renvoie la dernière chose calculée. Il se peut que vous vouliez, par exemple, quitter la fonction à partir du milieu de la fonction. Dans ce cas, vous pouvez utiliser le mot-clé <literal>return</literal>. <literal>Return</literal> prend un seul argument qui est la valeur renvoyée.</para>
      <para lang="en">
Example:
<programlisting lang="en"><![CDATA[function f(x) = (
  y=1;
  while true do (
    if x>50 then return y;
    y=y+1;
    x=x+1
  )
)
]]></programlisting>
      </para>
    </sect1>


    <sect1 id="genius-gel-references">
      <title>Références</title>
      <para>Il peut être nécessaire pour certaines fonctions de renvoyer plus d'une seule valeur. C'est possible en renvoyant un vecteur de valeurs mais souvent il est pratique d'utiliser le passage d'une référence à une variable. Vous transmettez une référence vers une variable à une fonction et la fonction attribue des valeurs à la variable pour vous en utilisant un déréférencement. Ce n'est pas le seul usage que vous pouvez faire du passage par référence mais c'est son utilisation principale.</para>
      <para lang="en">
	When using functions that return values through references
	in the argument list, just pass the variable name with an ampersand.
	For example the following code will compute an eigenvalue of a matrix
	<varname>A</varname> with initial eigenvector guess
	<varname>x</varname>, and store the computed eigenvector
	into the variable named <varname>v</varname>:
<programlisting lang="en"><![CDATA[RayleighQuotientIteration (A,x,0.001,100,&v)
]]></programlisting>
      </para>
      <para>Les détails concernant le fonctionnement des références et leur syntaxe sont similaires à ceux du langage C. L'opérateur <literal>&amp;</literal> référence une variable et <literal>*</literal> la déréférence. Les deux ne peuvent s'appliquer que sur un identifiant, par conséquent <literal>**a</literal> n'est pas une expression légale en GEL.</para>
      <para lang="en">
References are best explained by an example:
<programlisting lang="en"><![CDATA[a=1;
b=&a;
*b=2;
]]></programlisting>
now <varname>a</varname> contains 2.  You can also reference functions:
<programlisting lang="en"><![CDATA[function f(x) = x+1;
t=&f;
*t(3)
]]></programlisting>
gives us 4.
      </para>
    </sect1>

    <sect1 id="genius-gel-lvalues">
      <title>Valeurs à gauche (lvalues)</title>
      <para lang="en">
	An lvalue is the left hand side of an assignment. In other words, an
	lvalue is what you assign something to.  Valid lvalues are:
<variablelist>
  <varlistentry>
    <term lang="en"><userinput>a</userinput></term>
    <listitem>
      <para lang="en">
	Identifier.  Here we would be setting the variable of name
	<varname>a</varname>.
      </para>
    </listitem>
  </varlistentry>
  <varlistentry>
    <term lang="en"><userinput>*a</userinput></term>
    <listitem>
      <para lang="en">
	Dereference of an identifier.  This will set whatever variable
	<varname>a</varname> points to.
      </para>
    </listitem>
  </varlistentry>
  <varlistentry>
    <term lang="en"><userinput>a@(&lt;region&gt;)</userinput></term>
    <listitem>
      <para lang="en">
	A region of a matrix.  Here the region is specified normally as with
	the regular @() operator, and can be a single entry, or an entire
	region of the matrix.
      </para>
    </listitem>
  </varlistentry>
</variablelist>
      </para>
      <para lang="en">
Examples:
<programlisting lang="en">a:=4
*tmp := 89
a@(1,1) := 5
a@(4:8,3) := [1,2,3,4,5]'
</programlisting>
Note that both <literal>:=</literal> and <literal>=</literal> can be used
interchangeably.  Except if the assignment appears in a condition.
It is thus always safer to just use
<literal>:=</literal> when you mean assignment, and <literal>==</literal>
when you mean comparison.
      </para>
    </sect1>

  </chapter>

  <chapter id="genius-gel-programming-advanced">
    <title>Programmation avancée avec GEL</title>

    <sect1 id="genius-gel-error-handling">
      <title>Gestion des erreurs</title>
      <para>Si vous détectez une erreur dans votre fonction, vous pouvez la quitter rapidement (« to bail out of »). Pour les erreurs normales, telles que les mauvais types d'arguments, vous pouvez éviter de calculer la fonction en ajoutant l'instruction <literal>bailout</literal>. Si quelque chose se passe vraiment mal et que vous voulez interrompre complètement le calcul actuel, vous pouvez utiliser l'instruction <literal>exception</literal>.</para>
      <para lang="en">
	For example if you want to check for arguments in your function.  You
could use the following code.
<programlisting lang="en">function f(M) = (
  if not IsMatrix (M) then (
    error ("M not a matrix!");
    bailout
  );
  ...
)
</programlisting>
      </para>
    </sect1>

    <sect1 id="genius-gel-toplevel-syntax">
      <title>Syntaxe de haut-niveau</title>
      <para lang="en">
	The syntax is slightly different if you enter statements on
	the top level versus when they are inside parentheses or
	inside functions.  On the top level, enter acts the same as if
	you press return on the command line.  Therefore think of programs
	as just a sequence of lines as if they were entered on the command line.
	In particular, you do not need to enter the separator at the end of the
	line (unless it is part of several statements inside
	parentheses).  When a statement does not end with a separator on the
	top level, the result is printed after being executed.
      </para>
      <para lang="en">
	For example,
	<programlisting lang="en">function f(x)=x^2
f(3)
</programlisting>
	will print first the result of setting a function (a representation of
	the function, in this case <computeroutput>(`(x)=(x^2))</computeroutput>)
	and then the expected 9.  To avoid this, enter a separator
	after the function definition.
	<programlisting lang="en">function f(x)=x^2;
f(3)
</programlisting>
	If you need to put a separator into your function then you have to surround with
	parenthesis.  For example:
<programlisting lang="en">function f(x)=(
  y=1;
  for j=1 to x do
    y = y+j;
  y^2
);
</programlisting>
      </para>
      <para lang="en">
	The following code will produce an error when entered on the top
	level of a program, while it will work just fine in a function.
<programlisting lang="en">if Something() then
  DoSomething()
else
  DoSomethingElse()
</programlisting>
      </para>
      <para lang="en">
	The problem is that after <application>Genius Mathematics Tool</application> sees the end of line after the
	second line, it will decide that we have whole statement and
	it will execute it.  After the execution is done, <application>Genius Mathematics Tool</application> will
	go on to the next
	line, it will see <literal>else</literal>, and it will produce
	a parsing error.  To fix this, use parentheses.  <application>Genius Mathematics Tool</application> will not
	be satisfied until it has found that all parentheses are closed.
<programlisting lang="en">if Something() then (
  DoSomething()
) else (
  DoSomethingElse()
)
</programlisting>
      </para>
    </sect1>

     <sect1 id="genius-gel-returning-functions">
       <title>Renvoi de fonction</title>
	<para lang="en">
	  It is possible to return functions as value.  This way you can
	  build functions that construct special purpose functions according
	  to some parameters.  The tricky bit is what variables does the
	  function see.  The way this works in GEL is that when a function
	  returns another function, all identifiers referenced in the
	  function body that went out of scope
	  are prepended a private dictionary of the returned
	  function.  So the function will see all variables that were in
	  scope
	  when it was defined.  For example, we define a function that
	  returns a function that adds 5 to its argument.
<programlisting lang="en">function f() = (
  k = 5;
  `(x) = (x+k)
)
</programlisting>
	  Notice that the function adds <varname>k</varname> to
	  <varname>x</varname>.  You could use this as follows.
<programlisting lang="en">g = f();
g(5)
</programlisting>
	  And <userinput>g(5)</userinput> should return 10.
        </para>
	<para lang="en">
	  One thing to note is that the value of <varname>k</varname>
	  that is used is the one that's in effect when the
	  <function>f</function> returns.  For example:
<programlisting lang="en">function f() = (
  k := 5;
  function r(x) = (x+k);
  k := 10;
  r
)
</programlisting>
	  will return a function that adds 10 to its argument rather than
	  5.  This is because the extra dictionary is created only when
	  the context
	  in which the function was defined ends, which is when the function
	  <function>f</function> returns.  This is consistent with how you
	  would expect the function <function>r</function> to work inside
	  the function <function>f</function> according to the rules of
	  scope of variables in GEL.  Only those variables are added to the
	  extra dictionary that are in the context that just ended and
	  no longer exists.  Variables
	  used in the function that are in still valid contexts will work
	  as usual, using the current value of the variable.
	  The only difference is with global variables and functions.
	  All identifiers that referenced global variables at time of
	  the function definition are not added to the private dictionary.
	  This is to avoid much unnecessary work when returning functions
	  and would rarely be a problem.  For example, suppose that you
	  delete the "k=5" from the function <function>f</function>,
	  and at the top level you define <varname>k</varname> to be
	  say 5.  Then when you run <function>f</function>, the function
	  <function>r</function> will not put <varname>k</varname> into
	  the private dictionary because it was global (toplevel)
	  at the time of definition of <function>r</function>.
	</para>
	<para lang="en">
	  Sometimes it is better to have more control over how variables
	  are copied into the private dictionary.  Since version 1.0.7,
	  you can specify which
	  variables are copied into the private dictionary by putting
	  extra square brackets after the arguments with the list of
	  variables to be copied separated by commas.
	  If you do this, then variables are
	  copied into the private dictionary at time of the function
	  definition, and the private dictionary is not touched afterwards.
	  For example
<programlisting lang="en">function f() = (
  k := 5;
  function r(x) [k] = (x+k);
  k := 10;
  r
)
</programlisting>
	  will return a function that when called will add 5 to its
	  argument.  The local copy of <varname>k</varname> was created
	  when the function was defined.
	</para>
	<para lang="en">
	  When you want the function to not have any private dictionary
	  then put empty square brackets after the argument list.  Then
	  no private dictionary will be created at all.  Doing this is
	  good to increase efficiency when a private dictionary is not
	  needed or when you want the function to lookup all variables
	  as it sees them when called.  For example suppose you want
	  the function returned from <function>f</function> to see
	  the value of <varname>k</varname> from the toplevel despite
	  there being a local variable of the same name during definition.
	  So the code
<programlisting lang="en">function f() = (
  k := 5;
  function r(x) [] = (x+k);
  r
);
k := 10;
g = f();
g(10)
</programlisting>
	  will return 20 and not 15, which would happen if
	  <varname>k</varname> with a value of 5 was added to the private
	  dictionary.
	</para>
    </sect1>

    <sect1 id="genius-gel-true-local-variables">
      <title>Variables locales vraies</title>
      <para lang="en">
	When passing functions into other functions, the normal scoping of
	variables might be undesired.  For example:
<programlisting lang="en">k := 10;
function r(x) = (x+k);
function f(g,x) = (
  k := 5;
  g(x)
);
f(r,1)
</programlisting>
	you probably want the function <function>r</function>
	when passed as <function>g</function> into <function>f</function>
	to see <varname>k</varname> as 10 rather than 5, so that
	the code returns 11 and not 6.  However, as written, the function
	when executed will see the <varname>k</varname> that is
	equal to 5.  There are two ways to solve this.  One would be
	to have <function>r</function> get <varname>k</varname> in a
	private dictionary using the square bracket notation section
	<link linkend="genius-gel-returning-functions">Returning
	Functions</link>.
      </para>
      <para lang="en">
	But there is another solution.  Since version 1.0.7 there are
	true local variables.  These are variables that are visible only
	from the current context and not from any called functions.
	We could define <varname>k</varname> as a local variable in the
	function <function>f</function>.  To do this add a
	<command>local</command> statement as the first statement in the
	function (it must always be the first statement in the function).
	You can also make any arguments be local variables as well.
	That is,
<programlisting lang="en">function f(g,x) = (
  local g,x,k;
  k := 5;
  g(x)
);
</programlisting>
	Then the code will work as expected and prints out 11.
	Note that the <command>local</command> statement initializes
	all the referenced variables (except for function arguments) to
	a <constant>null</constant>.
      </para>
      <para lang="en">
	If all variables are to be created as locals you can just pass an
	asterisk instead of a list of variables.  In this case the variables
	will not be initialized until they are actually set.
	So the following definition of <function>f</function>
	will also work:
<programlisting lang="en">function f(g,x) = (
  local *;
  k := 5;
  g(x)
);
</programlisting>
      </para>
      <para>C'est une bonne pratique que toutes les fonctions qui prennent d'autres fonctions comme argument, utilisent des variables locales. De cette manière, la fonction transmise ne voit pas les détails de l'implémentation et n'est pas perturbée.</para>
    </sect1>

    <sect1 id="genius-gel-startup-procedure">
      <title>Procédure de démarrage de GEL</title>
      <para>Dans un premier temps, le programme recherche dans le répertoire d'installation les fichiers de la bibliothèque installés (la version compilée <filename>lib.cgel</filename>), puis il recherche dans le répertoire actuel, puis il essaye de charger un fichier non compilé appelé <filename>~/.geniusinit</filename>.</para>
      <para lang="en">
If you ever change the library in its installed place, you’ll have to
first compile it with <command>genius --compile loader.gel &gt; lib.cgel</command>
      </para>
    </sect1>

    <sect1 id="genius-gel-loading-programs">
      <title>Chargement de programmes</title>
      <para lang="en">
Sometimes you have a larger program you wrote into a file and want to read that file into <application>Genius Mathematics Tool</application>. In these situations, you have two options. You can keep the functions you use most inside the <filename>~/.geniusinit</filename> file. Or if you want to load up a file in a middle of a session (or from within another file), you can type <command>load &lt;list of filenames&gt;</command> at the prompt. This has to be done on the top level and not inside any function or whatnot, and it cannot be part of any expression. It also has a slightly different syntax than the rest of genius, more similar to a shell. You can enter the file in quotes. If you use the '' quotes, you will get exactly the string that you typed, if you use the "" quotes, special characters will be unescaped as they are for strings. Example:
<programlisting lang="en">load program1.gel program2.gel
load "Weird File Name With SPACES.gel"
</programlisting>
There are also <command>cd</command>, <command>pwd</command> and <command>ls</command> commands built in. <command>cd</command> will take one argument, <command>ls</command> will take an argument that is like the glob in the UNIX shell (i.e., you can use wildcards). <command>pwd</command> takes no arguments. For example:
<programlisting lang="en">cd directory_with_gel_programs
ls *.gel
</programlisting>
      </para>
    </sect1>

  </chapter>

  <!-- ============= Matrices ================================= -->
  <chapter id="genius-gel-matrices">
    <title>Matrices en GEL</title>

    <para lang="en">
      Genius has support for vectors and matrices and possesses a sizable library of
      matrix manipulation and linear algebra functions.
    </para>

    <sect1 id="genius-gel-matrix-support">
      <title>Saisie de matrices</title>
      <para lang="en">
To enter matrices, you can use one of the following two syntaxes. You can either enter
the matrix on one line, separating values by commas and rows by semicolons.  Or you
can enter each row on one line, separating
values by commas.
You can also just combine the two methods.
So to enter a 3x3 matrix
of numbers 1-9 you could do
<programlisting lang="en">[1,2,3;4,5,6;7,8,9]
</programlisting>
or
<programlisting lang="en">[1, 2, 3
 4, 5, 6
 7, 8, 9]
</programlisting>
Do not use both ';' and return at once on the same line though.
      </para>

      <para lang="en">
You can also use the matrix expansion functionality to enter matrices.
For example you can do:
<programlisting lang="en">a = [ 1, 2, 3
      4, 5, 6
      7, 8, 9]
b = [ a,  10
      11, 12]
</programlisting>
and you should get
<programlisting lang="en">[1,   2,  3, 10
 4,   5,  6, 10
 7,   8,  9, 10
 11, 11, 11, 12]
</programlisting>
similarly you can build matrices out of vectors and other stuff like that.
      </para>

      <para lang="en">
Another thing is that non-specified spots are initialized to 0, so
<programlisting lang="en">[1, 2, 3
 4, 5
 6]
</programlisting>
will end up being
<programlisting lang="en">
[1, 2, 3
 4, 5, 0
 6, 0, 0]
</programlisting>
      </para>

      <para lang="en">
	When matrices are evaluated, they are evaluated and traversed row-wise.  This is just
	like the <literal>M@(j)</literal> operator, which traverses the matrix row-wise.
      </para>

      <note>
        <para>Faites attention lorsque vous utilisez des retours à la ligne à l'intérieur des crochets <literal>[ ]</literal> car ils ont une signification légèrement différente dans ce cas. Vous commencez une nouvelle ligne.</para>
      </note>

    </sect1>

    <sect1 id="genius-gel-matrix-transpose">
      <title>Opérateur de transposition conjuguée et de transposition</title>
      <para lang="en">
You can conjugate transpose a matrix by using the <literal>'</literal> operator.  That is
the entry in the
<varname>i</varname>th column and the <varname>j</varname>th row will be
the complex conjugate of the entry in the
<varname>j</varname>th column and the <varname>i</varname>th row of the original matrix.
 For example:
<programlisting lang="en">[1,2,3]*[4,5,6]'
</programlisting>
We transpose the second vector to make matrix multiplication possible.
If you just want to transpose a matrix without conjugating it, you would
use the <literal>.'</literal> operator.  For example:
<programlisting lang="en">[1,2,3]*[4,5,6i].'
</programlisting>
      </para>
	<para>Remarquez que la transposée normale, c'est-à-dire l'opérateur <literal>.'</literal>, est beaucoup plus rapide et ne crée pas une nouvelle copie de la matrice en mémoire. La transposition conjuguée crée hélas une nouvelle copie. Il est recommandé de toujours utiliser l'opérateur <literal>.'</literal> lorsque vous travaillez avec des matrices et des vecteurs non complexes.</para>
    </sect1>

    <sect1 id="genius-gel-matrix-linalg">
      <title>Algèbre linéaire</title>
      <para>Genius implémente beaucoup de routines utiles d'algèbre linéraire et de manipulation de matrice. Consultez les sections <link linkend="genius-gel-function-list-linear-algebra">Algèbre linéaire</link> et <link linkend="genius-gel-function-list-matrix">Manipulation de matrice</link> dans la liste des fonctions GEL.</para>
      <para>Les routines d'algèbre linéaire implémentées en GEL ne proviennent pas actuellement d'un paquet numérique bien testé et ne doivent donc pas être utilisées pour des calculs numériques critiques. D'un autre côté, Genius implémente très bien les nombreuses opérations d'algèbre linéaire avec des coefficients rationnels et entiers. Elles sont par nature exactes et en fait vous donnent de bien meilleurs résultats que les routines en double précision usuelles pour l'algèbre linéaire.</para>
      <para>Par exemple, il est vain de calculer le rang et le noyau d'une matrice réelle puisque dans tous les cas pratiques, il faut considérer que la matrice contienne de légères erreurs. Il est possible que vous obteniez un résultat différent de ce que vous attendiez. Le problème est qu'en faisant une légère perturbation toute matrice est de rang complet et inversible. Cependant si la matrice est composée de nombres rationnels alors le rang et le noyau sont toujours exactes.</para>
      <para lang="en">
	In general when Genius computes the basis of a certain vectorspace
	(for example with the <link linkend="gel-function-NullSpace"><function>NullSpace</function></link>) it will give the basis as
a matrix, in which the columns are the vectors of the basis.  That is, when
Genius talks of a linear subspace it means a matrix whose column space is
the given linear subspace.
      </para>
      <para lang="en">
	It should be noted that Genius can remember certain properties of a
matrix.  For example, it will remember that a matrix is in row reduced form.
If many calls are made to functions that internally use row reduced form of
the matrix, we can just row reduce the matrix beforehand once.  Successive
calls to <link linkend="gel-function-rref"><function>rref</function></link> will be very fast.
      </para>
    </sect1>

  </chapter>

  <!-- ============= Polynomials ============================== -->
  <chapter id="genius-gel-polynomials">
    <title>Polynômes en GEL</title>

    <para>Actuellement Genius peut prendre en charge des polynômes à une variable écrits sous la forme de vecteurs et réaliser des opérations élémentaires avec eux. Il est prévu d'étendre cette prise en charge.</para>

    <sect1 id="genius-gel-polynomials-using">
      <title>Utilisation des polynômes</title>
      <para lang="en">
Currently
polynomials in one variable are just horizontal vectors with value only nodes.
The power of the term is the position in the vector, with the first position
being 0. So,
<programlisting lang="en">[1,2,3]
</programlisting>
translates to a polynomial of
<programlisting lang="en">1 + 2*x + 3*x^2
</programlisting>
      </para>
      <para lang="en">
You can add, subtract and multiply polynomials using the
<link linkend="gel-function-AddPoly"><function>AddPoly</function></link>,
<link linkend="gel-function-SubtractPoly"><function>SubtractPoly</function></link>, and
<link linkend="gel-function-MultiplyPoly"><function>MultiplyPoly</function></link> functions respectively.
You can print a polynomial using the
<link linkend="gel-function-PolyToString"><function>PolyToString</function></link>
function.
For example,
<programlisting lang="en">PolyToString([1,2,3],"y")
</programlisting>
gives
<programlisting lang="en">3*y^2 + 2*y + 1
</programlisting>
You can also get a function representation of the polynomial so that you can
evaluate it. This is done by using
<link linkend="gel-function-PolyToFunction"><function>PolyToFunction</function></link>,
which
returns an anonymous function.
<programlisting lang="en">f = PolyToFunction([0,1,1])
f(2)
</programlisting>
      </para>
      <para>Il est aussi possible de trouver les racines des polynômes de degré 1 à 4 en utilisant la fonction <link linkend="gel-function-PolynomialRoots"><function>PolynomialRoots</function></link> qui appelle la formule appropriée. Les polynômes de degré supérieur doit être convertis en fonctions et résolus numériquement en utilisant une fonction telle que <link linkend="gel-function-FindRootBisection"><function>FindRootBisection</function></link>, <link linkend="gel-function-FindRootFalsePosition"><function>FindRootFalsePosition</function></link>, <link linkend="gel-function-FindRootMullersMethod"><function>FindRootMullersMethod</function></link> ou <link linkend="gel-function-FindRootSecant"><function>FindRootSecant</function></link>.</para>
      <para>Consultez <xref linkend="genius-gel-function-list-polynomials"/> dans la liste des fonctions pour le reste des fonctions agissant sur les polynômes.</para>
    </sect1>

  </chapter>

  <!-- ============= Set Theory ============================== -->
  <chapter id="genius-gel-settheory">
    <title>Théorie des ensembles en GEL</title>

    <para>Genius possède des fonctionnalités intégrées basiques concernant la théorie des ensembles. Actuellement un ensemble est juste un vecteur (ou une matrice). Chaque objet distinct est traité comme un élément différent.</para>

    <sect1 id="genius-gel-sets-using">
      <title>Utilisation des ensembles</title>
      <para>Tout comme les vecteurs, les objets dans les ensembles peuvent comprendre des nombres, des chaînes de caractères, <constant>null</constant>, des matrices et des vecteurs. Il est prévu dans le futur d'avoir un type dédié pour les ensembles plutôt que d'utiliser des vecteurs. Notez que les nombres flottants sont différents des entiers, même s'ils semblent être les mêmes. Cela signifie que Genius traite <constant>0</constant> et <constant>0.0</constant> comme deux éléments différents. La constante <constant>null</constant> est traitée comme un ensemble vide.</para>
      <para lang="en">
	To build a set out of a vector, use the 
	<link linkend="gel-function-MakeSet"><function>MakeSet</function></link> function.
	Currently, it will just return a new vector where every element is unique.
<screen lang="en"><prompt>genius&gt; </prompt><userinput>MakeSet([1,2,2,3])</userinput>
= [1, 2, 3]
</screen>
</para>

	<para lang="en">
	Similarly there are functions 
	<link linkend="gel-function-Union"><function>Union</function></link>,
	<link linkend="gel-function-Intersection"><function>Intersection</function></link>,
	<link linkend="gel-function-SetMinus"><function>SetMinus</function></link>, which
	are rather self explanatory.  For example:
<screen lang="en"><prompt>genius&gt; </prompt><userinput>Union([1,2,3], [1,2,4])</userinput>
= [1, 2, 4, 3]
</screen>
	Note that no order is guaranteed for the return values.  If you wish to sort the vector you
should use the
	<link linkend="gel-function-SortVector"><function>SortVector</function></link> function.
	</para>

	<para lang="en">
	  For testing membership, there are functions
	<link linkend="gel-function-IsIn"><function>IsIn</function></link> and
	<link linkend="gel-function-IsSubset"><function>IsSubset</function></link>,
	which return a boolean value.  For example:
<screen lang="en"><prompt>genius&gt; </prompt><userinput>IsIn (1, [0,1,2])</userinput>
= true
</screen>
	The input <userinput>IsIn(x,X)</userinput> is equivalent to
	<userinput>IsSubset([x],X)</userinput>.  Note that since the empty set is a subset
	of every set, <userinput>IsSubset(null,X)</userinput> is always true.
	</para>

    </sect1>

  </chapter>

  <!-- ============= GEL function list ======================== -->
  <chapter id="genius-gel-function-list">
    <title>Liste des fonctions GEL</title>

    <!--&gel-function-list;-->

    <para lang="en">
To get help on a specific function from the console type:
<programlisting lang="en">help FunctionName
</programlisting>
    </para>

    <sect1 id="genius-gel-function-list-commands">
      <title>Commandes</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-command-help"/>help</term>
         <listitem>
          <synopsis>help</synopsis>
          <synopsis>help NomDeLaFonction</synopsis>
          <para>Affiche l'aide (ou l'aide d'une fonction/commande).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-command-load"/>load</term>
         <listitem>
          <synopsis>load "fichier.gel"</synopsis>
          <para lang="en">Load a file into the interpreter.  The file will execute
as if it were typed onto the command line.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-command-cd"/>cd</term>
         <listitem>
          <synopsis>cd /nom/de/repertoire</synopsis>
          <para>Change le répertoire de travail en <filename>/nom/de/repertoire</filename>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-command-pwd"/>pwd</term>
         <listitem>
          <synopsis>pwd</synopsis>
          <para>Affiche le répertoire de travail.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-command-ls"/>ls</term>
         <listitem>
          <synopsis>ls</synopsis>
          <para>Affiche les fichiers dans le répertoire.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-command-plugin"/>plugin</term>
         <listitem>
          <synopsis>plugin nom_du_greffon</synopsis>
          <para>Charge un greffon. Le greffon portant ce nom doit être installé sur votre système dans le répertoire correct.</para>
         </listitem>
        </varlistentry>
      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-basic">
      <title>Basique</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-AskButtons"/>AskButtons</term>
         <listitem>
          <synopsis>AskButtons (requête)</synopsis>
          <synopsis>AskButtons (requête, bouton1, ...)</synopsis>
	  <para>Pose une question et présente une liste de boutons à l'utilisateur (ou un menu d'options en mode texte). Renvoie l'indice du bouton enfoncé, commençant à 1, c'est-à-dire renvoie 1 si le premier bouton est enfoncé, 2 si le second bouton est enfoncé, etc. Si l'utilisateur ferme la fenêtre (ou appui sur Entrée en mode texte) alors <constant>null</constant> est renvoyé. L'exécution du programme est bloqué jusqu'à ce que l'utilisateur réponde.</para>
	  <para lang="en">Version 1.0.10 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-AskString"/>AskString</term>
         <listitem>
          <synopsis>AskString (requête)</synopsis>
          <synopsis>AskString (requête, défaut)</synopsis>
          <para lang="en">Asks a question and lets the user enter a string, which
it then returns.  If the user cancels or closes the window, then
<constant>null</constant> is returned.  The execution of the program
is blocked until the user responds.  If <varname>default</varname> is given, then it is pre-typed in for the user to just press enter on (version 1.0.6 onwards).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Compose"/>Compose</term>
         <listitem>
          <synopsis>Compose (f,g)</synopsis>
          <para>Compose deux fonctions et renvoie une fonction qui est la composition de <function>f</function> par <function>g</function>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ComposePower"/>ComposePower</term>
         <listitem>
          <synopsis>ComposePower (f,n,x)</synopsis>
          <para lang="en">Compose and execute a function with itself <varname>n</varname> times, passing <varname>x</varname> as argument.  Returning <varname>x</varname> if
<varname>n</varname> equals 0.
		Example:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>function f(x) = x^2 ;</userinput>
<prompt>genius&gt;</prompt> <userinput>ComposePower (f,3,7)</userinput>
= 5764801
<prompt>genius&gt;</prompt> <userinput>f(f(f(7)))</userinput>
= 5764801
</screen>
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Evaluate"/>Evaluate</term>
         <listitem>
          <synopsis>Evaluate (chaîne)</synopsis>
          <para>Analyse et évalue une chaîne.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><anchor id="gel-function-GetCurrentModulo"/>GetCurrentModulo</term>
         <listitem>
          <synopsis>GetCurrentModulo</synopsis>
          <para>Obtient le modulo actuel à partir du contexte extérieur à la fonction. C'est-à-dire, si l'extérieur de la fonction a été exécuté en mode modulo (en utilisant <literal>mod</literal>) alors cela renvoie cette valeur de modulo. Normalement le corps d'une fonction appelée n'est pas exécutée en arithmétique modulaire et cette fonction intégrée donne la possibilité aux fonctions GEL de prendre connaissance de l'arithmétique modulaire en cours.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Identity"/>Identity</term>
         <listitem>
          <synopsis>Identity (x)</synopsis>
	  <para lang="en">Identity function, returns its argument.  It is equivalent to <userinput>function Identity(x)=x</userinput>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IntegerFromBoolean"/>IntegerFromBoolean</term>
         <listitem>
          <synopsis>IntegerFromBoolean (val_bool)</synopsis>
	  <para>Crée un entier (0 pour <constant>false</constant> ou 1 pour <constant>true</constant>) à partir d'une valeur booléenne. <varname>val_bool</varname> peut également être un nombre et dans ce cas une valeur non nulle est interprétée comme <constant>true</constant> et zéro est interprété comme <constant>false</constant>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsBoolean"/>IsBoolean</term>
         <listitem>
          <synopsis>IsBoolean (param)</synopsis>
          <para>Vérifie que l'argument est un booléen (et pas un nombre).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsDefined"/>IsDefined</term>
         <listitem>
          <synopsis>IsDefined (id)</synopsis>
          <para>Vérifie qu'un identifiant est défini. Vous devez transmettre une chaîne de caractères ou un identifiant. Si vous transmettez une matrice, chaque entrée est évaluée séparément et la matrice doit contenir des chaînes ou des identifiants.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsFunction"/>IsFunction</term>
         <listitem>
          <synopsis>IsFunction (param)</synopsis>
          <para>Vérifie que l'argument est une fonction.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsFunctionOrIdentifier"/>IsFunctionOrIdentifier</term>
         <listitem>
          <synopsis>IsFunctionOrIdentifier (param)</synopsis>
          <para>Vérifie que l'argument est une fonction ou un identificateur.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsFunctionRef"/>IsFunctionRef</term>
         <listitem>
          <synopsis>IsFunctionRef (param)</synopsis>
          <para>Vérifie que l'argument est une référence de fonction. Cela inclut les références de variable.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsMatrix"/>IsMatrix</term>
         <listitem>
          <synopsis>IsMatrix (param)</synopsis>
          <para>Vérifie que l'argument est une matrice. Même si <constant>null</constant> est parfois considéré comme une matrice vide, la fonction <function>IsMatrix</function> ne considère pas <constant>null</constant> comme une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsNull"/>IsNull</term>
         <listitem>
          <synopsis>IsNull (param)</synopsis>
	  <para>Vérifie que l'argument est <constant>null</constant>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsString"/>IsString</term>
         <listitem>
          <synopsis>IsString (param)</synopsis>
          <para>Vérifie que l'argument est une chaîne de caractères.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsValue"/>IsValue</term>
         <listitem>
          <synopsis>IsValue (param)</synopsis>
          <para>Vérifie que l'argument est un nombre.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Parse"/>Parse</term>
         <listitem>
          <synopsis>Parse (chaîne)</synopsis>
          <para>Analyse mais n'évalue pas une chaîne de caractères. Notez que certains pré-calculs sont effectués pendant l'étape d'évaluation.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SetFunctionFlags"/>SetFunctionFlags</term>
         <listitem>
          <synopsis>SetFunctionFlags (id,drapeau...)</synopsis>
          <para>Définit des drapeaux pour une fonction, actuellement <literal>« PropagateMod »</literal> et <literal>« NoModuloArguments »</literal>. Si <literal>« PropagateMod »</literal> est défini alors le corps de la fonction est évalué en arithmétique modulaire lorsque la fonction est appelée à l'intérieur d'un bloc qui est évalué en utilisant l'arithmétique modulaire (en utilisant <literal>mod</literal>). Si <literal>« NoModuloArguments »</literal> est défini alors les arguments de la fonction ne sont jamais évalués en arithmétique modulaire.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SetHelp"/>SetHelp</term>
         <listitem>
          <synopsis>SetHelp (id,categorie,desc)</synopsis>
          <para>Définit une catégorie et une ligne de description d'aide pour une fonction.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SetHelpAlias"/>SetHelpAlias</term>
         <listitem>
          <synopsis>SetHelpAlias (id,alias)</synopsis>
          <para>Met en place un pseudonyme pour l'aide.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-chdir"/>chdir</term>
         <listitem>
          <synopsis>chdir (rep)</synopsis>
          <para>Change le répertoire actuel, tout comme la commande <command>cd</command>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CurrentTime"/>CurrentTime</term>
         <listitem>
          <synopsis>CurrentTime</synopsis>
          <para>Renvoie l'heure UNIX courante avec une précision de l'ordre de la microseconde sous forme d'un nombre à virgule flottante, c'est-à-dire le nombre de secondes écoulées depuis le 1er janvier 1970.</para>
	  <para lang="en">Version 1.0.15 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-display"/>display</term>
         <listitem>
          <synopsis>display (chaîne,expr)</synopsis>
          <para>Affiche une chaîne de caractères et une expression séparées par deux points.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DisplayVariables"/>DisplayVariables</term>
         <listitem>
          <synopsis lang="en">DisplayVariables (var1,var2,...)</synopsis>
	  <para lang="en">Display set of variables.  The variables can be given as
		  strings or identifiers.  For example:
	    <programlisting lang="en">DisplayVariables(`x,`y,`z)
	    </programlisting>
	  </para>
	  <para lang="en">
		  If called without arguments (must supply empty argument list) as
	    <programlisting lang="en">DisplayVariables()
	    </programlisting>
	    then all variables are printed including a stacktrace similar to
	    <guilabel>Show user variables</guilabel> in the graphical version.
	  </para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-error"/>error</term>
         <listitem>
          <synopsis>error (chaîne)</synopsis>
          <para>Affiche une chaîne vers la sortie erreur (dans la console).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-exit"/>exit</term>
         <listitem>
          <synopsis>exit</synopsis>
          <para>Alias : <function>quit</function></para>
          <para>Quitte le programme.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-false"/>false</term>
         <listitem>
          <synopsis>false</synopsis>
          <para lang="en">Aliases: <function>False</function> <function>FALSE</function></para>
	  <para>La valeur booléenne <constant>false</constant> (faux).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-manual"/>manual</term>
         <listitem>
          <synopsis>manual</synopsis>
          <para>Affiche le manuel utilisateur.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-print"/>print</term>
         <listitem>
          <synopsis>print (chaîne)</synopsis>
          <para>Affiche une expression suivie d'un retour à la ligne. L'argument <varname>chaine</varname> peut être n'importe quelle expression. Elle est transformée en chaîne avant d'être affichée.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-printn"/>printn</term>
         <listitem>
          <synopsis>printn (chaîne)</synopsis>
          <para>Affiche une expression non suivie d'un retour à la ligne. L'argument <varname>chaine</varname> peut être n'importe quelle expression. Elle est transformée en chaîne avant d'être affichée.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PrintTable"/>PrintTable</term>
         <listitem>
          <synopsis lang="en">PrintTable (f,v)</synopsis>
	  <para lang="en">Print a table of values for a function.  The values are in the 
		  vector <varname>v</varname>.  You can use the vector
		  building notation as follows:
      		  <programlisting lang="en">PrintTable (f,[0:10])
	    </programlisting>
	    If <varname>v</varname> is a positive integer, then the table of
	    integers from 1 up to and including v will be used.
	  </para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-protect"/>protect</term>
         <listitem>
          <synopsis>protect (id)</synopsis>
          <para>Protège une variable de la modification. C'est utilisé dans les fonctions internes de GEL pour leur éviter d'être accidentellement écrasées.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ProtectAll"/>ProtectAll</term>
         <listitem>
          <synopsis>ProtectAll ()</synopsis>
          <para>Protège toutes les variables, paramètres et fonctions actuellement définis de la modification. C'est utilisé dans les fonctions internes de GEL pour leur éviter d'être accidentellement écrasées. Normalement l'<application>Outil de maths Genius</application> considère que les variables non protégées sont définies par l'utilisateur.</para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-set"/>set</term>
         <listitem>
          <synopsis>set (id,val)</synopsis>
          <para lang="en">Set a global variable.  The <varname>id</varname>
            can be either a string or a quoted identifier.
	    For example:
	    <programlisting lang="en">set(`x,1)
	    </programlisting>
	    will set the global variable <varname>x</varname> to the value 1.
	  </para>
	  <para lang="en">The function returns the <varname>val</varname>, to be
	  usable in chaining.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SetElement"/>SetElement</term>
         <listitem>
          <synopsis lang="en">SetElement (id,row,col,val)</synopsis>
	  <para lang="en">Set an element of a global variable which is a matrix.
		  The <varname>id</varname>
            can be either a string or a quoted identifier.
	    For example:
	    <programlisting lang="en">SetElement(`x,2,3,1)
	    </programlisting>
	    will set the second row third column element of the global variable <varname>x</varname> to the value 1.  If no global variable of the name exists, or if it is set to something that's not a matrix, a new zero matrix of appropriate size will be created.
	  </para>
	  <para lang="en">The <varname>row</varname> and <varname>col</varname> can also be ranges, and the semantics are the same as for regular setting of the elements with an equals sign.
	  </para>
	  <para lang="en">The function returns the <varname>val</varname>, to be
	  usable in chaining.</para>
	  <para lang="en">Available from 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SetVElement"/>SetVElement</term>
         <listitem>
          <synopsis lang="en">SetElement (id,elt,val)</synopsis>
	  <para lang="en">Set an element of a global variable which is a vector.
		  The <varname>id</varname>
            can be either a string or a quoted identifier.
	    For example:
	    <programlisting lang="en">SetElement(`x,2,1)
	    </programlisting>
	    will set the second element of the global vector variable <varname>x</varname> to the value 1.  If no global variable of the name exists, or if it is set to something that's not a vector (matrix), a new zero row vector of appropriate size will be created.
	  </para>
	  <para lang="en">The <varname>elt</varname> can also be a range, and the semantics are the same as for regular setting of the elements with an equals sign.
	  </para>
	  <para lang="en">The function returns the <varname>val</varname>, to be
	  usable in chaining.</para>
	  <para lang="en">Available from 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-string"/>string</term>
         <listitem>
          <synopsis>string (s)</synopsis>
          <para>Crée une chaîne de caractères à partir de n'importe quel argument.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-true"/>true</term>
         <listitem>
          <synopsis>true</synopsis>
          <para lang="en">Aliases: <function>True</function> <function>TRUE</function></para>
	  <para>La valeur booléenne <constant>true</constant> (vrai).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-undefine"/>undefine</term>
         <listitem>
          <synopsis>undefine (id)</synopsis>
          <para>Alias : <function>Undefine</function></para>
          <para>Annule la définition d'une variable, y compris les variables locales et globales, toutes les valeurs dans tous les contextes sont effacées. Vous ne devriez vraiment pas utiliser cette fonction pour des variables locales. Un vecteur d'identifiants peut également être transmis pour annuler la définition de plusieurs variables.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-UndefineAll"/>UndefineAll</term>
         <listitem>
          <synopsis>UndefineAll ()</synopsis>
	  <para>Annule la définition de toutes les variables globales non protégées (y compris les fonctions et les paramètres). Normalement l'<application>Outil de maths Genius</application> considère que les variables protégées sont des variables et des fonctions définies par le système. Notez que <function>UndefineAll</function> efface seulement la définition globale des symboles et pas les définitions locales donc cela peut être utilisé à l'intérieur d'autres fonctions sans danger.</para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-unprotect"/>unprotect</term>
         <listitem>
          <synopsis>unprotect (id)</synopsis>
          <para>Annule la protection d'une variable contre sa modification.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-UserVariables"/>UserVariables</term>
         <listitem>
          <synopsis>UserVariables ()</synopsis>
          <para>Renvoie un vecteur d'identifiants des variables globales définies par l'utilisateur (non protégées).</para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-wait"/>wait</term>
         <listitem>
          <synopsis>wait (secs)</synopsis>
          <para>Attend un nombre spécifié de secondes. <varname>secs</varname> ne doit pas être négatif. Zéro est accepté et rien ne se passe dans ce cas mis à part, peut-être, le traitement d'évènements de l'interface utilisateur.</para>
	  <para lang="en">Since version 1.0.18, <varname>secs</varname> can be a noninteger number, so
		  <userinput>wait(0.1)</userinput> will wait for one tenth of a second.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-version"/>version</term>
         <listitem>
          <synopsis>version</synopsis>
          <para>Renvoie la version de Genius sous la forme d'un vecteur horizontal à 3 valeurs : en premier la version majeure, puis la version mineure et enfin le niveau de correction.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-warranty"/>warranty</term>
         <listitem>
          <synopsis>warranty</synopsis>
          <para>Renvoie les informations sur la garantie.</para>
         </listitem>
        </varlistentry>
      </variablelist>

    </sect1>

    <sect1 id="genius-gel-function-parameters">
      <title>Paramètres</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-ChopTolerance"/>ChopTolerance</term>
         <listitem>
          <synopsis>ChopTolerance = nombre</synopsis>
          <para>Tolérance pour la fonction <function>Chop</function>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ContinuousNumberOfTries"/>ContinuousNumberOfTries</term>
         <listitem>
          <synopsis>ContinuousNumberOfTries = nombre</synopsis>
          <para>Nombre d'itérations à essayer pour rechercher la continuité et les limites d'une fonction.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ContinuousSFS"/>ContinuousSFS</term>
         <listitem>
          <synopsis>ContinuousSFS = nombre</synopsis>
          <para>Nombre d'étapes successives pour atteindre la tolérance pour le calcul de la continuité.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ContinuousTolerance"/>ContinuousTolerance</term>
         <listitem>
          <synopsis>ContinuousTolerance = nombre</synopsis>
          <para>Tolérance pour la continuité d'une fonction et pour le calcul de la limite.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DerivativeNumberOfTries"/>DerivativeNumberOfTries</term>
         <listitem>
          <synopsis>DerivativeNumberOfTries = nombre</synopsis>
          <para>Nombre d'itérations à essayer pour trouver la limite pour la dérivée.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DerivativeSFS"/>DerivativeSFS</term>
         <listitem>
          <synopsis>DerivativeSFS = nombre</synopsis>
          <para>Nombre d'étapes successives pour atteindre la tolérance pour le calcul de la dérivée.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DerivativeTolerance"/>DerivativeTolerance</term>
         <listitem>
          <synopsis>DerivativeTolerance = nombre</synopsis>
          <para>Tolérance pour le calcul de la dérivée des fonctions.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ErrorFunctionTolerance"/>ErrorFunctionTolerance</term>
         <listitem>
          <synopsis>ErrorFunctionTolerance = nombre</synopsis>
	  <para lang="en">Tolerance of the <link linkend="gel-function-ErrorFunction"><function>ErrorFunction</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FloatPrecision"/>FloatPrecision</term>
         <listitem>
          <synopsis>FloatPrecision = nombre</synopsis>
          <para>Précision en virgule flottante.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FullExpressions"/>FullExpressions</term>
         <listitem>
          <synopsis>FullExpressions = booléen</synopsis>
          <para>Affiche les expressions complètes, même celles de plus d'une ligne.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-GaussDistributionTolerance"/>GaussDistributionTolerance</term>
         <listitem>
          <synopsis>GaussDistributionTolerance = nombre</synopsis>
	  <para lang="en">Tolerance of the <link linkend="gel-function-GaussDistribution"><function>GaussDistribution</function></link> function.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IntegerOutputBase"/>IntegerOutputBase</term>
         <listitem>
          <synopsis>IntegerOutputBase = nombre</synopsis>
          <para>Base de sortie pour les entiers.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPrimeMillerRabinReps"/>IsPrimeMillerRabinReps</term>
         <listitem>
          <synopsis>IsPrimeMillerRabinReps = nombre</synopsis>
	  <para lang="en">Number of extra Miller-Rabin tests to run on a number before declaring it a prime in <link linkend="gel-function-IsPrime"><function>IsPrime</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotDrawLegends"/>LinePlotDrawLegends</term>
         <listitem>
          <synopsis>LinePlotDrawLegends = true</synopsis>
          <para>Indique à genius de tracer les légendes pour les <link linkend="genius-gel-function-list-plotting">fonctions de tracé de graphiques</link> telles que <link linkend="gel-function-LinePlot"><function>LinePlot</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotDrawAxisLabels"/>LinePlotDrawAxisLabels</term>
         <listitem>
          <synopsis>LinePlotDrawAxisLabels = true</synopsis>
          <para lang="en">Tells genius to draw the axis labels for <link linkend="genius-gel-function-list-plotting">line plotting
	  functions</link> such as <link linkend="gel-function-LinePlot"><function>LinePlot</function></link>.
          </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotVariableNames"/>LinePlotVariableNames</term>
         <listitem>
          <synopsis>LinePlotVariableNames = ["x","y","z","t"]</synopsis>
          <para>Indique à Genius les noms des variables utilisés pour les <link linkend="genius-gel-function-list-plotting">fonctions de tracé de graphiques</link> telles que <link linkend="gel-function-LinePlot"><function>LinePlot</function></link> et autres.</para>
	  <para lang="en">Version 1.0.10 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotWindow"/>LinePlotWindow</term>
         <listitem>
          <synopsis>LinePlotWindow = [x1,x2,y1,y2]</synopsis>
          <para>Définit les limites pour les <link linkend="genius-gel-function-list-plotting">fonctions de tracé de graphiques</link> telles que <link linkend="gel-function-LinePlot"><function>LinePlot</function></link>.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><anchor id="gel-function-MaxDigits"/>MaxDigits</term>
         <listitem>
          <synopsis>MaxDigits = nombre</synopsis>
          <para>Nombre maximum de chiffres à afficher.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MaxErrors"/>MaxErrors</term>
         <listitem>
          <synopsis>MaxErrors = nombre</synopsis>
          <para>Nombre maximum d'erreurs à afficher.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MixedFractions"/>MixedFractions</term>
         <listitem>
          <synopsis>MixedFractions = booléen</synopsis>
          <para>Si vrai, les fractions mixtes sont affichées.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalIntegralFunction"/>NumericalIntegralFunction</term>
         <listitem>
          <synopsis>NumericalIntegralFunction = fonction</synopsis>
	  <para lang="en">The function used for numerical integration in <link linkend="gel-function-NumericalIntegral"><function>NumericalIntegral</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalIntegralSteps"/>NumericalIntegralSteps</term>
         <listitem>
          <synopsis>NumericalIntegralSteps = nombre</synopsis>
	  <para lang="en">Steps to perform in <link linkend="gel-function-NumericalIntegral"><function>NumericalIntegral</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-OutputChopExponent"/>OutputChopExponent</term>
         <listitem>
          <synopsis>OutputChopExponent = nombre</synopsis>
	  <para>Lorsqu'un autre nombre dans l'objet qui est affiché (une matrice ou une valeur) est plus grand que 10<superscript>-OutputChopWhenExponent</superscript> et que le nombre actuellement affiché est inférieur à 10<superscript>-OutputChopExponent</superscript> alors afficher <computeroutput>0.0</computeroutput> au lieu du nombre.</para>
<para>La sortie n'est jamais tronquée si <function>OutputChopExponent</function> vaut zéro. Cela doit être un nombre entier positif.</para>
<para>Si vous voulez toujours que la sortie soit tronquée selon <function>OutputChopExponent</function> alors définissez <function>OutputChopWhenExponent</function> à quelque chose de supérieur ou égal à <function>OutputChopExponent</function>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-OutputChopWhenExponent"/>OutputChopWhenExponent</term>
         <listitem>
          <synopsis>OutputChopWhenExponent = nombre</synopsis>
	  <para>Définit quand la sortie est tronquée. Consultez <link linkend="gel-function-OutputChopExponent"><function>OutputChopExponent</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-OutputStyle"/>OutputStyle</term>
         <listitem>
          <synopsis>OutputStyle = chaîne</synopsis>
          <para>Style des affichages, cela peut être <literal>normal</literal>, <literal>latex</literal>, <literal>mathml</literal> ou <literal>troff</literal>.</para>
	  <para lang="en">
	    This affects mostly how matrices and fractions are printed out and
	    is useful for pasting into documents.  For example you can set this
	    to the latex by:
	    <programlisting lang="en">OutputStyle = "latex"
</programlisting>
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ResultsAsFloats"/>ResultsAsFloats</term>
         <listitem>
          <synopsis>ResultsAsFloats = booléen</synopsis>
          <para>Convertit tous les résultats en nombres flottants avant de les afficher.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ScientificNotation"/>ScientificNotation</term>
         <listitem>
          <synopsis>ScientificNotation = booléen</synopsis>
          <para>Utilise la notation scientifique.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SlopefieldTicks"/>SlopefieldTicks</term>
         <listitem>
          <synopsis>SlopefieldTicks = [verticale,horizontale]</synopsis>
          <para>Définit le nombre de petits traits verticaux et horizontaux dans un graphique de champ de tangente (consultez <link linkend="gel-function-SlopefieldPlot"><function>SlopefieldPlot</function></link>).</para>
	  <para lang="en">Version 1.0.10 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SumProductNumberOfTries"/>SumProductNumberOfTries</term>
         <listitem>
          <synopsis>SumProductNumberOfTries = nombre</synopsis>
	  <para lang="en">How many iterations to try for <link linkend="gel-function-InfiniteSum"><function>InfiniteSum</function></link> and <link linkend="gel-function-InfiniteProduct"><function>InfiniteProduct</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SumProductSFS"/>SumProductSFS</term>
         <listitem>
          <synopsis>SumProductSFS = nombre</synopsis>
          <para lang="en">How many successive steps to be within tolerance for <link linkend="gel-function-InfiniteSum"><function>InfiniteSum</function></link> and <link linkend="gel-function-InfiniteProduct"><function>InfiniteProduct</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SumProductTolerance"/>SumProductTolerance</term>
         <listitem>
          <synopsis>SumProductTolerance = nombre</synopsis>
          <para lang="en">Tolerance for <link linkend="gel-function-InfiniteSum"><function>InfiniteSum</function></link> and <link linkend="gel-function-InfiniteProduct"><function>InfiniteProduct</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SurfacePlotDrawLegends"/>SurfacePlotDrawLegends</term>
         <listitem>
          <synopsis>SurfacePlotDrawLegends = true</synopsis>
          <para lang="en">Tells genius to draw the legends for <link linkend="genius-gel-function-list-plotting">surface plotting
	  functions</link> such as <link linkend="gel-function-SurfacePlot"><function>SurfacePlot</function></link>.
          </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SurfacePlotVariableNames"/>SurfacePlotVariableNames</term>
         <listitem>
          <synopsis>SurfacePlotVariableNames = ["x","y","z"]</synopsis>
          <para lang="en">Tells genius which variable names are used as default names for <link linkend="genius-gel-function-list-plotting">surface plotting
	  functions</link> using <link linkend="gel-function-SurfacePlot"><function>SurfacePlot</function></link>.
          Note that the <varname>z</varname> does not refer to the dependent (vertical) axis, but to the independent complex variable
          <userinput>z=x+iy</userinput>.
          </para>
	  <para lang="en">Version 1.0.10 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SurfacePlotWindow"/>SurfacePlotWindow</term>
         <listitem>
          <synopsis>SurfacePlotWindow = [x1,x2,y1,y2,z1,z2]</synopsis>
          <para>Définit les limites pour les tracés de surface (consultez <link linkend="gel-function-SurfacePlot"><function>SurfacePlot</function></link>).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorfieldNormalized"/>VectorfieldNormalized</term>
         <listitem>
          <synopsis>VectorfieldNormalized = true</synopsis>
          <para>Indique si les longueurs de flèches du tracé de champ de vecteurs doivent être normalisées. Si true (vrai), les tracés de champ de vecteurs n'affichent que la direction et pas l'amplitude (consultez <link linkend="gel-function-VectorfieldPlot"><function>VectorfieldPlot</function></link>).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorfieldTicks"/>VectorfieldTicks</term>
         <listitem>
          <synopsis>VectorfieldTicks = [verticale,horizontale]</synopsis>
          <para>Définit le nombre de petits traits verticaux et horizontaux dans un graphique de champ de vecteurs (consultez <link linkend="gel-function-SlopefieldPlot"><function>VectorfieldPlot</function></link>).</para>
	  <para lang="en">Version 1.0.10 onwards.</para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-constants">
      <title>Constantes</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-CatalanConstant"/>CatalanConstant</term>
         <listitem>
          <synopsis>CatalanConstant</synopsis>
          <para>Constante de Catalan, approximativement 0,915..., elle est définie comme la série des termes <userinput>(-1^k)/((2*k+1)^2)</userinput> où <varname>k</varname> va de 0 à l'infini.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Catalan%27s_constant">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/CatalansConstant.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-EulerConstant"/>EulerConstant</term>
         <listitem>
          <synopsis>EulerConstant</synopsis>
          <para>Alias : <function>gamma</function></para>
          <para lang="en">
	    Euler's constant gamma.  Sometimes called the
	    Euler-Mascheroni constant.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Euler-Mascheroni_constant">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/MascheroniConstant">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/Euler-MascheroniConstant.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-GoldenRatio"/>GoldenRatio</term>
         <listitem>
          <synopsis>GoldenRatio</synopsis>
          <para>Le nombre d'or.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Golden_ratio">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/GoldenRatio">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/GoldenRatio.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Gravity"/>Gravity</term>
         <listitem>
          <synopsis>Gravity</synopsis>
	  <para lang="en">Free fall acceleration at sea level in meters per second squared.  This is the standard gravity constant 9.80665.  The gravity
		  in your particular neck of the woods might be different due to different altitude and the fact that the earth is not perfectly
	  	  round and uniform.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Standard_gravity">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-e"/>e</term>
         <listitem>
          <synopsis>e</synopsis>
          <para lang="en">
	    The base of the natural logarithm.  <userinput>e^x</userinput>
	    is the exponential function
	    <link linkend="gel-function-exp"><function>exp</function></link>.  It is approximately
	    2.71828182846...  This number is sometimes called Euler's number, although there are
	    several numbers that are also called Euler's.  An example is the gamma constant: <link linkend="gel-function-EulerConstant"><function>EulerConstant</function></link>.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/E_(mathematical_constant)">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/E">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/e.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-pi"/>pi</term>
         <listitem>
          <synopsis>pi</synopsis>
          <para>Le nombre pi, c'est-à-dire le rapport de la circonférence d'un cercle sur son diamètre. Il vaut approximativement 3.14159265359...</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Pi">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/Pi">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/Pi.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-numeric">
      <title>Nombres</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-AbsoluteValue"/>AbsoluteValue</term>
         <listitem>
          <synopsis>AbsoluteValue (x)</synopsis>
          <para>Alias : <function>abs</function></para>
          <para lang="en">
	    Absolute value of a number and if <varname>x</varname> is
	    a complex value the modulus of <varname>x</varname>.  I.e. this
	    the distance of <varname>x</varname> to the origin.  This is equivalent
	    to <userinput>|x|</userinput>.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Absolute_value">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/AbsoluteValue">Planetmath (absolute value)</ulink>,
	    <ulink url="http://planetmath.org/ModulusOfComplexNumber">Planetmath (modulus)</ulink>,
	    <ulink url="http://mathworld.wolfram.com/AbsoluteValue.html">Mathworld (absolute value)</ulink> or
	    <ulink url="http://mathworld.wolfram.com/ComplexModulus.html">Mathworld (complex modulus)</ulink>
for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Chop"/>Chop</term>
         <listitem>
          <synopsis>Chop (x)</synopsis>
          <para>Remplace les très petits nombres par zéro.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ComplexConjugate"/>ComplexConjugate</term>
         <listitem>
          <synopsis>ComplexConjugate (z)</synopsis>
          <para lang="en">Aliases: <function>conj</function> <function>Conj</function></para>
          <para>Calcule le conjugué du nombre complexe <varname>z</varname>. Si <varname>z</varname> est un vecteur ou une matrice, tous les éléments sont conjugués.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Complex_conjugate">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Denominator"/>Denominator</term>
         <listitem>
          <synopsis>Denominator (x)</synopsis>
          <para>Renvoie le dénominateur d'un nombre rationnel.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Denominator">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FractionalPart"/>FractionalPart</term>
         <listitem>
          <synopsis>FractionalPart (x)</synopsis>
          <para>Renvoie la partie fractionnelle d'un nombre.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fractional_part">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Im"/>Im</term>
         <listitem>
          <synopsis>Im (z)</synopsis>
          <para>Alias : <function>ImaginaryPart</function></para>
          <para lang="en">Get the imaginary part of a complex number.  For example <userinput>Re(3+4i)</userinput> yields 4.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Imaginary_part">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IntegerQuotient"/>IntegerQuotient</term>
         <listitem>
          <synopsis>IntegerQuotient (m,n)</synopsis>
          <para>Division sans reste.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsComplex"/>IsComplex</term>
         <listitem>
          <synopsis>IsComplex (nbre)</synopsis>
	  <para lang="en">Check if argument is a complex (non-real) number.  Do note that we really mean nonreal number.  That is,
	  <userinput>IsComplex(3)</userinput> yields false, while
	  <userinput>IsComplex(3-1i)</userinput> yields true.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsComplexRational"/>IsComplexRational</term>
         <listitem>
          <synopsis>IsComplexRational (nbre)</synopsis>
	  <para>Vérifie si l'argument est potentiellement un nombre rationnel complexe. C'est-à-dire si la partie réelle et la partie imaginaire sont fournies sous la forme de nombres rationnels. Bien sûr, rationnel signifie simplement « non enregistré comme un nombre à virgule flottante ».</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsFloat"/>IsFloat</term>
         <listitem>
          <synopsis>IsFloat (nbre)</synopsis>
          <para lang="en">Check if argument is a real floating point number (non-complex).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsGaussInteger"/>IsGaussInteger</term>
         <listitem>
          <synopsis>IsGaussInteger (nbre)</synopsis>
          <para>Alias : <function>IsComplexInteger</function></para>
	  <para lang="en">Check if argument is a possibly complex integer.  That is a complex integer is a number of
		  the form <userinput>n+1i*m</userinput> where <varname>n</varname> and <varname>m</varname>
	  are integers.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsInteger"/>IsInteger</term>
         <listitem>
          <synopsis>IsInteger (nbre)</synopsis>
          <para>Vérifie si l'argument est un entier (non complexe).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsNonNegativeInteger"/>IsNonNegativeInteger</term>
         <listitem>
          <synopsis>IsNonNegativeInteger (nbre)</synopsis>
          <para lang="en">Check if argument is a non-negative real integer.  That is, either a positive integer or zero.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPositiveInteger"/>IsPositiveInteger</term>
         <listitem>
          <synopsis>IsPositiveInteger (nbre)</synopsis>
          <para>Alias : <function>IsNaturalNumber</function></para>
          <para>Vérifie si l'argument est un entier réel positif. Notez que par convention 0 n'est pas un nombre naturel.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsRational"/>IsRational</term>
         <listitem>
          <synopsis>IsRational (nbre)</synopsis>
          <para>Vérifie si l'argument est un nombre rationnel (non complexe). Bien sûr, rationnel signifie simplement « non enregistré comme un nombre à virgule flottante ».</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsReal"/>IsReal</term>
         <listitem>
          <synopsis>IsReal (nbre)</synopsis>
          <para>Vérifie si l'argument est un nombre réel.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Numerator"/>Numerator</term>
         <listitem>
          <synopsis>Numerator (x)</synopsis>
          <para>Renvoie le numérateur d'un nombre rationnel.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Numerator">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Re"/>Re</term>
         <listitem>
          <synopsis>Re (z)</synopsis>
          <para>Alias : <function>RealPart</function></para>
	  <para lang="en">Get the real part of a complex number.  For example <userinput>Re(3+4i)</userinput> yields 3.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Real_part">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Sign"/>Sign</term>
         <listitem>
          <synopsis>Sign (x)</synopsis>
          <para>Alias : <function>sign</function></para>
          <para>Renvoie le signe d'un nombre. C'est-à-dire renvoie <literal>-1</literal> si la valeur est négative, <literal>0</literal> si la valeur est nulle et <literal>1</literal> si la valeur est positive. Si <varname>x</varname> est une grandeur complexe alors <function>Sign</function> renvoie la direction ou 0.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ceil"/>ceil</term>
         <listitem>
          <synopsis>ceil (x)</synopsis>
          <para>Alias : <function>Ceiling</function></para>
	  <para lang="en">Get the lowest integer more than or equal to <varname>n</varname>. Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>ceil(1.1)</userinput>
= 2
<prompt>genius&gt;</prompt> <userinput>ceil(-1.1)</userinput>
= -1
</screen>
           </para>
	   <para lang="en">Note that you should be careful and notice that floating point
		   numbers are stored in binary and so may not be what you
		   expect.  For example <userinput>ceil(420/4.2)</userinput>
		   returns 101 instead of the expected 100.  This is because
		   4.2 is actually very slightly less than 4.2.  Use rational
		   representation <userinput>42/10</userinput> if you want
		   exact arithmetic.
           </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-exp"/>exp</term>
         <listitem>
          <synopsis>exp (x)</synopsis>
          <para>La fonction exponentielle. C'est la fonction <userinput>e^x</userinput> où <varname>e</varname> est la <link linkend="gel-function-e">base du logarithme naturel</link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Exponential_function">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/LogarithmFunction">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/ExponentialFunction.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-float"/>float</term>
         <listitem>
          <synopsis>float (x)</synopsis>
          <para>Transforme le nombre en nombre à virgule flottante. C'est-à-dire la représentation à virgule flottante du nombre <varname>x</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-floor"/>floor</term>
         <listitem>
          <synopsis>floor (x)</synopsis>
          <para>Alias : <function>Floor</function></para>
          <para>Renvoie le plus grand entier inférieur ou égal à <varname>n</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ln"/>ln</term>
         <listitem>
          <synopsis>ln (x)</synopsis>
          <para>Le logarithme naturel, le logarithme de base <varname>e</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Natural_logarithm">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/LogarithmFunction">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/NaturalLogarithm.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-log"/>log</term>
         <listitem>
          <synopsis>log (x)</synopsis>
          <synopsis>log (x,b)</synopsis>
	  <para lang="en">Logarithm of <varname>x</varname> base <varname>b</varname> (calls <link linkend="gel-function-DiscreteLog"><function>DiscreteLog</function></link> if in modulo mode), if base is not given, <link linkend="gel-function-e"><varname>e</varname></link> is used.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-log10"/>log10</term>
         <listitem>
          <synopsis>log10 (x)</synopsis>
          <para>Logarithme base 10 de <varname>x</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-log2"/>log2</term>
         <listitem>
          <synopsis>log2 (x)</synopsis>
          <para>Alias : <function>lg</function></para>
          <para>Logarithme base 2 de <varname>x</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-max"/>max</term>
         <listitem>
          <synopsis>max (a,params...)</synopsis>
          <para lang="en">Aliases: <function>Max</function> <function>Maximum</function></para>
          <para>Renvoie le maximum des arguments ou de la matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-min"/>min</term>
         <listitem>
          <synopsis>min (a,params...)</synopsis>
          <para lang="en">Aliases: <function>Min</function> <function>Minimum</function></para>
          <para>Renvoie le minimum des arguments ou de la matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-rand"/>rand</term>
         <listitem>
          <synopsis>rand (taille...)</synopsis>
          <para>Génère aléatoirement des nombres flottants dans l'intervalle <literal>[0,1)</literal>. Si taille est donnée alors une matrice (si deux nombres sont fournis) ou un vecteur (si un seul est fourni) de la taille indiquée est renvoyé.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-randint"/>randint</term>
         <listitem>
          <synopsis>randint (max,taille...)</synopsis>
          <para lang="en">Generate random integer in the range
<literal>[0,max)</literal>.
If size is given then a matrix (if two numbers are specified) or vector (if one
number is specified) of the given size returned.  For example,
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>randint(4)</userinput>
= 3
<prompt>genius&gt;</prompt> <userinput>randint(4,2)</userinput>
=
[0      1]
<prompt>genius&gt;</prompt> <userinput>randint(4,2,3)</userinput>
=
[2      2       1
 0      0       3]
</screen>
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-round"/>round</term>
         <listitem>
          <synopsis>round (x)</synopsis>
          <para>Alias : <function>Round</function></para>
          <para>Arrondit un nombre.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-sqrt"/>sqrt</term>
         <listitem>
          <synopsis>sqrt (x)</synopsis>
          <para>Alias : <function>SquareRoot</function></para>
          <para lang="en">The square root.  When operating modulo some integer will return either a <constant>null</constant> or a vector of the square roots.  Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>sqrt(2)</userinput>
= 1.41421356237
<prompt>genius&gt;</prompt> <userinput>sqrt(-1)</userinput>
= 1i
<prompt>genius&gt;</prompt> <userinput>sqrt(4) mod 7</userinput>
=
[2      5]
<prompt>genius&gt;</prompt> <userinput>2*2 mod 7</userinput>
= 4
</screen>
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Square_root">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/SquareRoot">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-trunc"/>trunc</term>
         <listitem>
          <synopsis>trunc (x)</synopsis>
          <para lang="en">Aliases: <function>Truncate</function> <function>IntegerPart</function></para>
          <para>Tronque le nombre à un entier (renvoie la partie entière).</para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-trigonometry">
      <title>Trigonométrie</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-acos"/>acos</term>
         <listitem>
          <synopsis>acos (x)</synopsis>
          <para>Alias : <function>arccos</function></para>
          <para>Fonction arccos (arc cosinus).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-acosh"/>acosh</term>
         <listitem>
          <synopsis>acosh (x)</synopsis>
          <para>Alias : <function>arccosh</function></para>
          <para>Fonction arccosh (cosinus hyperbolique inverse).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-acot"/>acot</term>
         <listitem>
          <synopsis>acot (x)</synopsis>
          <para>Alias : <function>arccot</function></para>
          <para>Fonction arccot (cotangente inverse).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-acoth"/>acoth</term>
         <listitem>
          <synopsis>acoth (x)</synopsis>
          <para>Alias : <function>arccoth</function></para>
          <para>Fonction arccoth (cotangente hyperbolique inverse).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-acsc"/>acsc</term>
         <listitem>
          <synopsis>acsc (x)</synopsis>
          <para>Alias : <function>arccsc</function></para>
          <para>Inverse de la fonction cosécante.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-acsch"/>acsch</term>
         <listitem>
          <synopsis>acsch (x)</synopsis>
          <para>Alias : <function>arccsch</function></para>
          <para>Inverse de la fonction cosécante hyperbolique.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-asec"/>asec</term>
         <listitem>
          <synopsis>asec (x)</synopsis>
          <para>Alias : <function>arcsec</function></para>
          <para>Inverse de la fonction sécante.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-asech"/>asech</term>
         <listitem>
          <synopsis>asech (x)</synopsis>
          <para>Alias : <function>arcsech</function></para>
          <para>Inverse de la fontion sécante hyperbolique.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-asin"/>asin</term>
         <listitem>
          <synopsis>asin (x)</synopsis>
          <para>Alias : <function>arcsin</function></para>
          <para>La fonction arcsin (sinus inverse).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-asinh"/>asinh</term>
         <listitem>
          <synopsis>asinh (x)</synopsis>
          <para>Alias : <function>arcsinh</function></para>
          <para>Fonction arcsinh (sinus hyperbolique inverse).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-atan"/>atan</term>
         <listitem>
          <synopsis>atan (x)</synopsis>
          <para>Alias : <function>arctan</function></para>
          <para>Calcule la fonction arctangente (tangente inverse).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Arctangent">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/InverseTangent.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-atanh"/>atanh</term>
         <listitem>
          <synopsis>atanh (x)</synopsis>
          <para>Alias : <function>arctanh</function></para>
          <para>Fonction arctanh (tangente hyperbolique inverse).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-atan2"/>atan2</term>
         <listitem>
          <synopsis>atan2 (y, x)</synopsis>
          <para>Alias : <function>arctan2</function></para>
          <para lang="en">Calculates the arctan2 function.  If
	  <userinput>x&gt;0</userinput> then it returns
	  <userinput>atan(y/x)</userinput>.  If <userinput>x&lt;0</userinput>
	  then it returns <userinput>sign(y) * (pi - atan(|y/x|)</userinput>.
	  When <userinput>x=0</userinput> it returns <userinput>sign(y) *
	  pi/2</userinput>.  <userinput>atan2(0,0)</userinput> returns 0
	  rather than failing.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Atan2">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/InverseTangent.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-cos"/>cos</term>
         <listitem>
          <synopsis>cos (x)</synopsis>
          <para>Calcule la fonction cosinus.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Trigonometric_functions">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DefinitionsInTrigonometry">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-cosh"/>cosh</term>
         <listitem>
          <synopsis>cosh (x)</synopsis>
          <para>Calcule la fonction cosinus hyperbolique.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hyperbolic_function">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HyperbolicFunctions">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-cot"/>cot</term>
         <listitem>
          <synopsis>cot (x)</synopsis>
          <para>Fonction cotangente.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Trigonometric_functions">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DefinitionsInTrigonometry">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-coth"/>coth</term>
         <listitem>
          <synopsis>coth (x)</synopsis>
          <para>Fonction cotangente hyperbolique.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hyperbolic_function">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HyperbolicFunctions">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-csc"/>csc</term>
         <listitem>
          <synopsis>csc (x)</synopsis>
          <para>Fonction cosécante.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Trigonometric_functions">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DefinitionsInTrigonometry">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-csch"/>csch</term>
         <listitem>
          <synopsis>csch (x)</synopsis>
          <para>Fonction cosécante hyperbolique.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hyperbolic_function">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HyperbolicFunctions">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-sec"/>sec</term>
         <listitem>
          <synopsis>sec (x)</synopsis>
          <para>Fonction sécante.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Trigonometric_functions">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DefinitionsInTrigonometry">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-sech"/>sech</term>
         <listitem>
          <synopsis>sech (x)</synopsis>
          <para>Fonction sécante hyperbolique.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hyperbolic_function">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HyperbolicFunctions">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-sin"/>sin</term>
         <listitem>
          <synopsis>sin (x)</synopsis>
          <para>Calcule la fonction sinus.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Trigonometric_functions">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DefinitionsInTrigonometry">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-sinh"/>sinh</term>
         <listitem>
          <synopsis>sinh (x)</synopsis>
          <para>Calcule la fonction sinus hyperbolique.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hyperbolic_function">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HyperbolicFunctions">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-tan"/>tan</term>
         <listitem>
          <synopsis>tan (x)</synopsis>
          <para>Calcule la fonction tangente.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Trigonometric_functions">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DefinitionsInTrigonometry">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-tanh"/>tanh</term>
         <listitem>
          <synopsis>tanh (x)</synopsis>
          <para>Fonction tangente hyperbolique.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hyperbolic_function">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HyperbolicFunctions">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-number-theory">
      <title>Théorie des nombres</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-AreRelativelyPrime"/>AreRelativelyPrime</term>
         <listitem>
          <synopsis>AreRelativelyPrime (a,b)</synopsis>
          <para>Si les entiers <varname>a</varname> et <varname>b</varname> sont premiers entre eux ? Renvoie <constant>true</constant> (vrai) ou <constant>false</constant> (faux).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Coprime_integers">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/RelativelyPrime">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/RelativelyPrime.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BernoulliNumber"/>BernoulliNumber</term>
         <listitem>
          <synopsis>BernoulliNumber (n)</synopsis>
          <para>Renvoie le <varname>n</varname>-ième nombre de Bernoulli.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Bernoulli_number">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/BernoulliNumber.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ChineseRemainder"/>ChineseRemainder</term>
         <listitem>
          <synopsis>ChineseRemainder (a,m)</synopsis>
          <para>Alias : <function>CRT</function></para>
	  <para>Recherche <varname>x</varname> qui résout le système défini par le vecteur <varname>a</varname> et modulo les éléments de <varname>m</varname>, en utilisant le théorème des restes chinois.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Chinese_remainder_theorem">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/ChineseRemainderTheorem">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/ChineseRemainderTheorem.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CombineFactorizations"/>CombineFactorizations</term>
         <listitem>
          <synopsis>CombineFactorizations (a,b)</synopsis>
	  <para>Étant donné deux factorisations, donne la factorisation du produit.</para>
	  <para>Consultez <link linkend="gel-function-Factorize">Factorize</link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ConvertFromBase"/>ConvertFromBase</term>
         <listitem>
          <synopsis>ConvertFromBase (v,b)</synopsis>
          <para>Convertit un vecteur de valeurs indiquant les puissances de b en un nombre.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ConvertToBase"/>ConvertToBase</term>
         <listitem>
          <synopsis>ConvertToBase (n,b)</synopsis>
          <para>Convertit un nombre en un vecteur contenant les puissances des éléments dans la base <varname>b</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DiscreteLog"/>DiscreteLog</term>
         <listitem>
          <synopsis>DiscreteLog (n,b,q)</synopsis>
          <para>Calcule le logarithme discret de <varname>n</varname> base <varname>b</varname> dans F<subscript>q</subscript>, le corps fini d'ordre <varname>q</varname> où <varname>q</varname> est un nombre premier, en utilisant l'algorithme de Silver-Pohlig-Hellman.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Discrete_logarithm">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/DiscreteLogarithm">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/DiscreteLogarithm.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Divides"/>Divides</term>
         <listitem>
          <synopsis>Divides (m,n)</synopsis>
          <para>Vérifie la divisibilité (si <varname>m</varname> divise <varname>n</varname>).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-EulerPhi"/>EulerPhi</term>
         <listitem>
          <synopsis>EulerPhi (n)</synopsis>
          <para>Calcule la fonction d'Euler phi, c'est-à-dire le nombre d'entiers compris entre 1 et <varname>n</varname> qui sont premiers avec <varname>n</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Euler_phi">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/EulerPhifunction">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/TotientFunction.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ExactDivision"/>ExactDivision</term>
         <listitem>
          <synopsis>ExactDivision (n,d)</synopsis>
          <para lang="en">
	    Return <userinput>n/d</userinput> but only if <varname>d</varname>
	    divides <varname>n</varname>.  If <varname>d</varname>
	    does not divide <varname>n</varname> then this function returns
	    garbage.  This is a lot faster for very large numbers
	    than the operation <userinput>n/d</userinput>, but it is only
	    useful if you know that the division is exact.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Factorize"/>Factorize</term>
         <listitem>
          <synopsis>Factorize (n)</synopsis>
          <para lang="en">
	    Return factorization of a number as a matrix.  The first
	    row is the primes in the factorization (including 1) and the
	    second row are the powers.  So for example:
	    <screen lang="en"><prompt>genius&gt;</prompt> <userinput>Factorize(11*11*13)</userinput>
=
[1      11      13
 1      2       1]</screen>
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Factorization">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Factors"/>Factors</term>
         <listitem>
          <synopsis>Factors (n)</synopsis>
          <para lang="en">
	    Return all factors of <varname>n</varname> in a vector.  This
	    includes all the non-prime factors as well.  It includes 1 and the
	    number itself.  So to print all the perfect numbers
	    (those that are sums of their factors) up to the number 1000 you
	    could do (this is clearly very inefficient)
	    <programlisting lang="en">for n=1 to 1000 do (
    if MatrixSum (Factors(n)) == 2*n then
        print(n)
)
</programlisting>
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FermatFactorization"/>FermatFactorization</term>
         <listitem>
          <synopsis>FermatFactorization (n,tentatives)</synopsis>
          <para lang="en">
	    Attempt Fermat factorization of <varname>n</varname> into
	    <userinput>(t-s)*(t+s)</userinput>, returns <varname>t</varname>
	    and <varname>s</varname> as a vector if possible, <constant>null</constant> otherwise.
	    <varname>tries</varname> specifies the number of tries before
	    giving up.
	  </para>
          <para>C'est une assez bonne factorisation si votre nombre est le produit de deux facteurs très proches l'un de l'autre.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fermat_factorization">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FindPrimitiveElementMod"/>FindPrimitiveElementMod</term>
         <listitem>
          <synopsis>FindPrimitiveElementMod (q)</synopsis>
          <para>Cherche le premier élément primitif dans F<subscript>q</subscript>, le groupe fini d'ordre <varname>q</varname>. Bien sûr, <varname>q</varname> doit être premier.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FindRandomPrimitiveElementMod"/>FindRandomPrimitiveElementMod</term>
         <listitem>
          <synopsis>FindRandomPrimitiveElementMod (q)</synopsis>
          <para>Cherche un élément primitif au hasard dans F<subscript>q</subscript>, le groupe fini d'ordre <varname>q</varname> (q doit être premier).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IndexCalculus"/>IndexCalculus</term>
         <listitem>
          <synopsis>IndexCalculus (n,b,q,S)</synopsis>
          <para lang="en">Compute discrete log base <varname>b</varname> of n in F<subscript>q</subscript>, the finite
group of order <varname>q</varname> (<varname>q</varname> a prime), using the
factor base <varname>S</varname>.  <varname>S</varname> should be a column of
primes possibly with second column precalculated by
<link linkend="gel-function-IndexCalculusPrecalculation"><function>IndexCalculusPrecalculation</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IndexCalculusPrecalculation"/>IndexCalculusPrecalculation</term>
         <listitem>
          <synopsis>IndexCalculusPrecalculation (b,q,S)</synopsis>
	  <para lang="en">Run the precalculation step of
		  <link linkend="gel-function-IndexCalculus"><function>IndexCalculus</function></link> for logarithms base <varname>b</varname> in
F<subscript>q</subscript>, the finite group of order <varname>q</varname>
(<varname>q</varname> a prime), for the factor base <varname>S</varname> (where
<varname>S</varname> is a column vector of primes).  The logs will be
precalculated and returned in the second column.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsEven"/>IsEven</term>
         <listitem>
          <synopsis>IsEven (n)</synopsis>
          <para>Teste si un entier est pair.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsMersennePrimeExponent"/>IsMersennePrimeExponent</term>
         <listitem>
          <synopsis>IsMersennePrimeExponent (p)</synopsis>
          <para lang="en">
	    Tests if a positive integer <varname>p</varname> is a
	    Mersenne prime exponent.  That is if 
            2<superscript>p</superscript>-1 is a prime.  It does this
	    by looking it up in a table of known values, which is relatively
	    short.
	    See also
	    <link linkend="gel-function-MersennePrimeExponents">MersennePrimeExponents</link>
	    and
	    <link linkend="gel-function-LucasLehmer">LucasLehmer</link>.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Mersenne_prime">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/MersenneNumbers">Planetmath</ulink>,
	    <ulink url="http://mathworld.wolfram.com/MersennePrime.html">Mathworld</ulink> or 
	    <ulink url="http://www.mersenne.org/">GIMPS</ulink>
 for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsNthPower"/>IsNthPower</term>
         <listitem>
          <synopsis>IsNthPower (m,n)</synopsis>
          <para>Vérifie si un nombre rationnel <varname>m</varname> est une puissance <varname>n</varname>-ième parfaite. Consultez aussi <link linkend="gel-function-IsPerfectPower">IsPerfectPower</link> et <link linkend="gel-function-IsPerfectSquare">IsPerfectSquare</link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsOdd"/>IsOdd</term>
         <listitem>
          <synopsis>IsOdd (n)</synopsis>
          <para>Teste si un entier est impair.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPerfectPower"/>IsPerfectPower</term>
         <listitem>
          <synopsis>IsPerfectPower (n)</synopsis>
          <para lang="en">Check an integer for being any perfect power, a<superscript>b</superscript>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPerfectSquare"/>IsPerfectSquare</term>
         <listitem>
          <synopsis>IsPerfectSquare (n)</synopsis>
          <para lang="en">
	    Check an integer for being a perfect square of an integer.  The number must
	    be an integer.  Negative integers are never perfect
	    squares of integers.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPrime"/>IsPrime</term>
         <listitem>
          <synopsis>IsPrime (n)</synopsis>
          <para lang="en">
	    Tests primality of integers, for numbers less than 2.5e10 the
	    answer is deterministic (if Riemann hypothesis is true).  For
	    numbers larger, the probability of a false positive
	    depends on
	    <link linkend="gel-function-IsPrimeMillerRabinReps">
	    <function>IsPrimeMillerRabinReps</function></link>.  That
	    is the probability of false positive is 1/4 to the power
	    <function>IsPrimeMillerRabinReps</function>.  The default
	    value of 22 yields a probability of about 5.7e-14.
	  </para>
          <para lang="en">
	    If <constant>false</constant> is returned, you can be sure that
	    the number is a composite.  If you want to be absolutely sure
	    that you have a prime you can use 
	    <link linkend="gel-function-MillerRabinTestSure">
	    <function>MillerRabinTestSure</function></link> but it may take
	    a lot longer.
	  </para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/PrimeNumber">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/PrimeNumber.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPrimitiveMod"/>IsPrimitiveMod</term>
         <listitem>
          <synopsis>IsPrimitiveMod (g,q)</synopsis>
          <para>Vérifie que <varname>g</varname> est primitif dans F<subscript>q</subscript>, le groupe fini d'ordre <varname>q</varname>, où <varname>q</varname> est premier. Si <varname>q</varname> n'est pas premier, les résultats sont erronés.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPrimitiveModWithPrimeFactors"/>IsPrimitiveModWithPrimeFactors</term>
         <listitem>
          <synopsis>IsPrimitiveModWithPrimeFactors (g,q,f)</synopsis>
          <para>Vérifie que <varname>g</varname> est primitif dans F<subscript>q</subscript>, le groupe fini d'ordre <varname>q</varname>, où <varname>q</varname> est premier et <varname>f</varname> est un vecteur de facteurs premiers de <varname>q</varname>-1. Si <varname>q</varname> n'est pas premier, les résultats sont erronés.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPseudoprime"/>IsPseudoprime</term>
         <listitem>
          <synopsis>IsPseudoprime (n,b)</synopsis>
          <para lang="en">If <varname>n</varname> is a pseudoprime base <varname>b</varname> but not a prime,
		  that is if <userinput>b^(n-1) == 1 mod n</userinput>.  This calls the <link linkend="gel-function-PseudoprimeTest"><function>PseudoprimeTest</function></link></para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsStrongPseudoprime"/>IsStrongPseudoprime</term>
         <listitem>
          <synopsis>IsStrongPseudoprime (n,b)</synopsis>
          <para>Teste si <varname>n</varname> est un nombre pseudopremier fort en base <varname>b</varname> mais pas un nombre premier.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Jacobi"/>Jacobi</term>
         <listitem>
          <synopsis>Jacobi (a,b)</synopsis>
          <para>Alias : <function>JacobiSymbol</function></para>
          <para>Calcule le symbole de Jacobi (a/b) (b doit être impair).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-JacobiKronecker"/>JacobiKronecker</term>
         <listitem>
          <synopsis>JacobiKronecker (a,b)</synopsis>
          <para>Alias : <function>JacobiKroneckerSymbol</function></para>
          <para>Calcule le symbole de Jacobi (a/b) avec l'extension de Kronecker (a/2)=(2/a) si impair, ou (a/2)=0 si pair.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LeastAbsoluteResidue"/>LeastAbsoluteResidue</term>
         <listitem>
          <synopsis>LeastAbsoluteResidue (a,n)</synopsis>
          <para>Renvoie le résidu de <varname>a</varname> modulo <varname>n</varname> avec la plus petite valeur absolue (entre -n/2 et n/2).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Legendre"/>Legendre</term>
         <listitem>
          <synopsis>Legendre (a,p)</synopsis>
          <para>Alias : <function>LegendreSymbol</function></para>
          <para>Calcule le symbole de Legendre (a/p).</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/LegendreSymbol">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/LegendreSymbol.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LucasLehmer"/>LucasLehmer</term>
         <listitem>
          <synopsis>LucasLehmer (p)</synopsis>
          <para>Teste si 2<superscript>p</superscript>-1 est un nombre premier de Mersenne en utilisant le test de Lucas-Lehmer. Consultez aussi <link linkend="gel-function-MersennePrimeExponents">MersennePrimeExponents</link> et <link linkend="gel-function-IsMersennePrimeExponent">IsMersennePrimeExponent</link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Lucas%E2%80%93Lehmer_primality_test">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/LucasLhemer">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/Lucas-LehmerTest.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LucasNumber"/>LucasNumber</term>
         <listitem>
          <synopsis>LucasNumber (n)</synopsis>
          <para>Renvoie le <varname>n</varname>-ième nombre de Lucas.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Lucas_number">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/LucasNumbers">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/LucasNumber.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MaximalPrimePowerFactors"/>MaximalPrimePowerFactors</term>
         <listitem>
          <synopsis>MaximalPrimePowerFactors (n)</synopsis>
          <para>Renvoie les puissances premières d'un nombre.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MersennePrimeExponents"/>MersennePrimeExponents</term>
         <listitem>
          <synopsis>MersennePrimeExponents</synopsis>
          <para>Renvoie un vecteur de nombres premiers de Mersenne qui est une liste d'entiers positifs <varname>p</varname> tels que 2<superscript>p</superscript>-1 est entier. Consultez aussi <link linkend="gel-function-IsMersennePrimeExponent">IsMersennePrimeExponent</link> et <link linkend="gel-function-LucasLehmer">LucasLehmer</link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Mersenne_prime">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/MersenneNumbers">Planetmath</ulink>,
	    <ulink url="http://mathworld.wolfram.com/MersennePrime.html">Mathworld</ulink> or 
	    <ulink url="http://www.mersenne.org/">GIMPS</ulink>
 for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MillerRabinTest"/>MillerRabinTest</term>
         <listitem>
          <synopsis>MillerRabinTest (n,reps)</synopsis>
          <para lang="en">
	    Use the Miller-Rabin primality test on <varname>n</varname>,
	    <varname>reps</varname> number of times.  The probability of false
	    positive is <userinput>(1/4)^reps</userinput>.  It is probably
	    usually better to use
	    <link linkend="gel-function-IsPrime">
	    <function>IsPrime</function></link> since that is faster and
	    better on smaller integers.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/MillerRabinPrimeTest">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/Rabin-MillerStrongPseudoprimeTest.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MillerRabinTestSure"/>MillerRabinTestSure</term>
         <listitem>
          <synopsis>MillerRabinTestSure (n)</synopsis>
          <para lang="en">
	    Use the Miller-Rabin primality test on <varname>n</varname> with
	    enough bases that assuming the Generalized Riemann Hypothesis the
	    result is deterministic.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/MillerRabinPrimeTest">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/Rabin-MillerStrongPseudoprimeTest.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ModInvert"/>ModInvert</term>
         <listitem>
          <synopsis>ModInvert (n,m)</synopsis>
          <para>Renvoie l'inverse de n mod m.</para>
          <para>Consultez <ulink url="http://mathworld.wolfram.com/ModularInverse.html">Mathworld</ulink> pour plus d'informations.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MoebiusMu"/>MoebiusMu</term>
         <listitem>
          <synopsis>MoebiusMu (n)</synopsis>
          <para>Renvoie la fonction mu de Moebius évaluée dans <varname>n</varname>. C'est-à-dire renvoie 0 si <varname>n</varname> n'est pas un produit de nombres premiers différents et <userinput>(-1)^k</userinput> si c'est un produit de <varname>k</varname> nombres premiers différents.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/MoebiusFunction">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/MoebiusFunction.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NextPrime"/>NextPrime</term>
         <listitem>
          <synopsis>NextPrime (n)</synopsis>
          <para>Renvoie le plus petit nombre premier supérieur à <varname>n</varname>. L'opposé d'un nombre premier est considéré comme un nombre premier donc pour obtenir le nombre premier précédent, vous pouvez utiliser <userinput>-NextPrime(-n)</userinput>.</para>
          <para lang="en">
	    This function uses the GMPs <function>mpz_nextprime</function>,
	    which in turn uses the probabilistic Miller-Rabin test
	    (See also <link linkend="gel-function-MillerRabinTest"><function>MillerRabinTest</function></link>).
	    The probability
	    of false positive is not tunable, but is low enough
	    for all practical purposes.
	  </para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/PrimeNumber">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/PrimeNumber.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PadicValuation"/>PadicValuation</term>
         <listitem>
          <synopsis>PadicValuation (n,p)</synopsis>
          <para>Renvoie la valuation p-adic (nombre de zéros après la virgule en base <varname>p</varname>).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/P-adic_order">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/PAdicValuation">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PowerMod"/>PowerMod</term>
         <listitem>
          <synopsis>PowerMod (a,b,m)</synopsis>
          <para lang="en">
	    Compute <userinput>a^b mod m</userinput>.  The
	    <varname>b</varname>'s power of <varname>a</varname> modulo
	    <varname>m</varname>.  It is not necessary to use this function
	    as it is automatically used in modulo mode.  Hence
	    <userinput>a^b mod m</userinput> is just as fast.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Prime"/>Prime</term>
         <listitem>
          <synopsis>Prime (n)</synopsis>
          <para>Alias : <function>prime</function></para>
          <para>Renvoie le <varname>n</varname>-ième nombre premier (jusqu'à une limite) .</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/PrimeNumber">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/PrimeNumber.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PrimeFactors"/>PrimeFactors</term>
         <listitem>
          <synopsis>PrimeFactors (n)</synopsis>
          <para>Renvoie tous les facteurs premiers d'un nombre sous la forme d'un vecteur.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Prime_factor">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/PrimeFactor.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PseudoprimeTest"/>PseudoprimeTest</term>
         <listitem>
          <synopsis>PseudoprimeTest (n,b)</synopsis>
	  <para lang="en">Pseudoprime test, returns <constant>true</constant> if and only if
		<userinput>b^(n-1) == 1  mod n</userinput></para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/Pseudoprime">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/Pseudoprime.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RemoveFactor"/>RemoveFactor</term>
         <listitem>
          <synopsis>RemoveFactor (n,m)</synopsis>
          <para>Supprime toutes les instances du facteur <varname>m</varname> dans le nombre <varname>n</varname>. C'est-à-dire divise par la plus grande puissance de <varname>m</varname> qui divise <varname>n</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/Divisibility">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/Factor.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SilverPohligHellmanWithFactorization"/>SilverPohligHellmanWithFactorization</term>
         <listitem>
          <synopsis>SilverPohligHellmanWithFactorization (n,b,q,f)</synopsis>
          <para>Calcule le logarithme discret de <varname>n</varname> base <varname>b</varname> dans F<subscript>q</subscript>, le corps fini d'ordre <varname>q</varname> où <varname>q</varname> est un nombre premier, en utilisant l'algorithme de Silver-Pohlig-Hellman, sachant que <varname>f</varname> est la factorisation de <varname>q</varname>-1.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SqrtModPrime"/>SqrtModPrime</term>
         <listitem>
          <synopsis>SqrtModPrime (n,p)</synopsis>
          <para>Cherche la racine carrée de <varname>n</varname> modulo <varname>p</varname> (où <varname>p</varname> est premier). <constant>null</constant> est renvoyé si ce n'est pas un résidu quadratique.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/QuadraticResidue">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/QuadraticResidue.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-StrongPseudoprimeTest"/>StrongPseudoprimeTest</term>
         <listitem>
          <synopsis>StrongPseudoprimeTest (n,b)</synopsis>
          <para>Lance le test de pseudo-primarité forte en base <varname>b</varname> sur <varname>n</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Strong_pseudoprime">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/StrongPseudoprime">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/StrongPseudoprime.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-gcd"/>gcd</term>
         <listitem>
          <synopsis>gcd (a,params...)</synopsis>
          <para>Alias : <function>GCD</function></para>
          <para lang="en">
	    Greatest common divisor of integers.  You can enter as many
	    integers as you want in the argument list, or you can give
	    a vector or a matrix of integers.  If you give more than
	    one matrix of the same size then GCD is done element by
	    element.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Greatest_common_divisor">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/GreatestCommonDivisor">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/GreatestCommonDivisor.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-lcm"/>lcm</term>
         <listitem>
          <synopsis>lcm (a,params...)</synopsis>
          <para>Alias : <function>LCM</function></para>
          <para lang="en">
	    Least common multiplier of integers.  You can enter as many
	    integers as you want in the argument list, or you can give a 
	    vector or a matrix of integers.  If you give more than one
	    matrix of the same size then LCM is done element by element.    
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Least_common_multiple">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/LeastCommonMultiple">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/LeastCommonMultiple.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-matrix">
      <title>Manipulation de matrices</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-AppendElement"/>AppendElement</term>
         <listitem>
          <synopsis lang="en">AppendElement (v,elt)</synopsis>
	  <para lang="en">Append an element to a vector and return the vector.  No expansion is done.  Normally
		  a row vector is built if starting from <constant>null</constant> or a 1-by-1 matrix,
		  but if given a column vector it will properly build a column vector.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ApplyOverMatrix"/>ApplyOverMatrix</term>
         <listitem>
          <synopsis>ApplyOverMatrix (a,fonc)</synopsis>
          <para>Applique une fonction sur tous les éléments d'une matrice et renvoie une matrice de résultats.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ApplyOverMatrix2"/>ApplyOverMatrix2</term>
         <listitem>
          <synopsis>ApplyOverMatrix2 (a,b,fonc)</synopsis>
          <para>Applique une fonction sur tous les éléments de 2 matrices (ou 1 valeur et 1 matrice) et renvoie une matrice de résultats.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ColumnsOf"/>ColumnsOf</term>
         <listitem>
          <synopsis>ColumnsOf (M)</synopsis>
          <para>Extrait les colonnes de la matrice comme un vecteur horizontal.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ComplementSubmatrix"/>ComplementSubmatrix</term>
         <listitem>
          <synopsis>ComplementSubmatrix (m,r,c)</synopsis>
          <para>Supprime certaines lignes et colonnes d'une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CompoundMatrix"/>CompoundMatrix</term>
         <listitem>
          <synopsis>CompoundMatrix (k,A)</synopsis>
          <para>Calcule la k-ième matrice composée de A.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CountZeroColumns"/>CountZeroColumns</term>
         <listitem>
          <synopsis>CountZeroColumns (M)</synopsis>
          <para lang="en">
	   Count the number of zero columns in a matrix.  For example,
	   once you column-reduce a matrix, you can use this to find
	   the nullity.  See <link linkend="gel-function-cref"><function>cref</function></link>
	   and <link linkend="gel-function-Nullity"><function>Nullity</function></link>.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DeleteColumn"/>DeleteColumn</term>
         <listitem>
          <synopsis>DeleteColumn (M,col)</synopsis>
          <para>Supprime une colonne d'une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DeleteRow"/>DeleteRow</term>
         <listitem>
          <synopsis>DeleteRow (M,row)</synopsis>
          <para>Supprime une ligne d'une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DiagonalOf"/>DiagonalOf</term>
         <listitem>
          <synopsis>DiagonalOf (M)</synopsis>
          <para>Extrait la diagonale de la matrice comme un vecteur colonne.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Diagonal_of_a_matrix#Matrices">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DotProduct"/>DotProduct</term>
         <listitem>
          <synopsis>DotProduct (u,v)</synopsis>
	  <para lang="en">Get the dot product of two vectors.  The vectors must be of the
		  same size.  No conjugates are taken so this is a bilinear form even if working over the complex numbers; This is the bilinear scalar product not the sesquilinear scalar product.  See <link linkend="gel-function-HermitianProduct">HermitianProduct</link> for the standard sesquilinear inner product.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Dot_product">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DotProduct">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ExpandMatrix"/>ExpandMatrix</term>
         <listitem>
          <synopsis>ExpandMatrix (M)</synopsis>
          <para>Développe une matrice exactement comme cela est fait lors de la saisie d'une matrice non précédée d'une apostrophe. Cela signifie que toute matrice interne est développée sous la forme de blocs. C'est une façon de construire des matrices à partir de matrices plus petites et c'est ce qui est effectué normalement de manière automatique lors d'une saisie à moins que la matrice ne soit précédée d'une apostrophe.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-HermitianProduct"/>HermitianProduct</term>
         <listitem>
          <synopsis>HermitianProduct (u,v)</synopsis>
          <para>Alias : <function>InnerProduct</function></para>
          <para>Renvoie le produit hermitienne de deux vecteurs. Les vecteurs doivent avoir la même taille. C'est une forme sesquilinéaire utilisant la matrice identité.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Sesquilinear_form">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/HermitianInnerProduct.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-I"/>I</term>
         <listitem>
          <synopsis>I (n)</synopsis>
          <para>Alias : <function>eye</function></para>
	  <para>Renvoie une matrice identité de la taille indiquée, soit une matrice de <varname>n</varname> par <varname>n</varname>. Si <varname>n</varname> vaut zéro, renvoie <constant>null</constant>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Identity_matrix">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/IdentityMatrix">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IndexComplement"/>IndexComplement</term>
         <listitem>
          <synopsis>IndexComplement (vec,mtaille)</synopsis>
          <para>Renvoie le complémentaire d'un vecteur d'indices. Le premier indice est toujours 1. Par exemple pour le vecteur <userinput>[2,3]</userinput> et la taille <userinput>5</userinput>, cela renvoie <userinput>[1,4,5]</userinput>. Si <varname>mtaille</varname> vaut 0, cela renvoie toujours <constant>null</constant>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsDiagonal"/>IsDiagonal</term>
         <listitem>
          <synopsis>IsDiagonal (M)</synopsis>
          <para>Indique si la matrice est diagonale.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Diagonal_matrix">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DiagonalMatrix">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsIdentity"/>IsIdentity</term>
         <listitem>
          <synopsis>IsIdentity (x)</synopsis>
          <para>Vérifie qu'une matrice est la matrice identité. Renvoie automatiquement <constant>false</constant> (faux) si la matrice n'est pas carrée. Fonctionne également avec les nombres et dans ce cas, c'est équivalent à <userinput>x==1</userinput>. Lorsque <varname>x</varname> est <constant>null</constant>, il est considéré comme une matrice 0 par 0, aucune erreur n'est générée et <constant>false</constant> (faux) est renvoyé.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsLowerTriangular"/>IsLowerTriangular</term>
         <listitem>
          <synopsis>IsLowerTriangular (M)</synopsis>
          <para>Indique si une matrice est triangulaire inférieure, c'est-à-dire que toutes les valeurs au dessus de la diagonale sont nulles.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsMatrixInteger"/>IsMatrixInteger</term>
         <listitem>
          <synopsis>IsMatrixInteger (M)</synopsis>
          <para lang="en">Check if a matrix is a matrix of integers (non-complex).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsMatrixNonnegative"/>IsMatrixNonnegative</term>
         <listitem>
          <synopsis>IsMatrixNonnegative (M)</synopsis>
          <para>Vérifie si une matrice est non négative, c'est-à-dire que chaque élément n'est pas négatif. Ne pas confondre les matrices positives avec les matrices définies positives.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Positive_matrix">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsMatrixPositive"/>IsMatrixPositive</term>
         <listitem>
          <synopsis>IsMatrixPositive (M)</synopsis>
	  <para>Vérifie si une matrice est positive, c'est-à-dire que chaque élément est positif (et par conséquent réel), et en particulier qu'aucun élément n'est nul. Ne pas confondre les matrices positives avec les matrices définies positives</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Positive_matrix">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsMatrixRational"/>IsMatrixRational</term>
         <listitem>
          <synopsis>IsMatrixRational (M)</synopsis>
          <para>Vérifie si une matrice est constituée de nombres rationnels (non complexes).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsMatrixReal"/>IsMatrixReal</term>
         <listitem>
          <synopsis>IsMatrixReal (M)</synopsis>
          <para>Vérifie si une matrice est constituée de nombres réels (non complexes).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsMatrixSquare"/>IsMatrixSquare</term>
         <listitem>
          <synopsis>IsMatrixSquare (M)</synopsis>
          <para>Vérifie si une matrice est carrée, c'est-à-dire que sa largeur est égale à sa hauteur.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsUpperTriangular"/>IsUpperTriangular</term>
         <listitem>
          <synopsis>IsUpperTriangular (M)</synopsis>
          <para lang="en">Is a matrix upper triangular?  That is, a matrix is upper triangular if all the entries below the diagonal are zero.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsValueOnly"/>IsValueOnly</term>
         <listitem>
          <synopsis>IsValueOnly (M)</synopsis>
          <para>Vérifie si une matrice est une matrice de nombres seulement. Beaucoup de fonctions internes contrôlent cela. Les valeurs peuvent être n'importe quels nombres y compris des complexes.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsVector"/>IsVector</term>
         <listitem>
          <synopsis>IsVector (v)</synopsis>
          <para>Si l'argument est un vecteur horizontal ou vertical. Genius ne fait pas de distinction entre une matrice et un vecteur, un vecteur est juste une matrice 1 par <varname>n</varname> ou <varname>n</varname> par 1.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsZero"/>IsZero</term>
         <listitem>
          <synopsis>IsZero (x)</synopsis>
          <para>Vérifie si une matrice est composée uniquement de zéros. Fonctionne également avec les nombres et dans ce cas, c'est équivalent à <userinput>x==0</userinput>. Lorsque <varname>x</varname> est <constant>null</constant>, il est considéré comme une matrice 0 par 0, aucune erreur n'est générée et <constant>true</constant> (vrai) est renvoyé car la condition est vide.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LowerTriangular"/>LowerTriangular</term>
         <listitem>
          <synopsis>LowerTriangular (M)</synopsis>
          <para>Renvoie une copie de la matrice <varname>M</varname> avec tous les éléments au dessus de la diagonale mis à zéro.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MakeDiagonal"/>MakeDiagonal</term>
         <listitem>
          <synopsis>MakeDiagonal (v,param...)</synopsis>
          <para>Alias : <function>diag</function></para>
	  <para lang="en">Make diagonal matrix from a vector.  Alternatively you can pass
		  in the values to put on the diagonal as arguments.  So
		  <userinput>MakeDiagonal([1,2,3])</userinput> is the same as
		  <userinput>MakeDiagonal(1,2,3)</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Diagonal_matrix">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/DiagonalMatrix">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MakeVector"/>MakeVector</term>
         <listitem>
          <synopsis>MakeVector (A)</synopsis>
          <para lang="en">Alias: <function>MakeColumnVector</function></para>
          <para lang="en">Make column vector out of matrix by putting columns above
		  each other.  Returns <constant>null</constant> when given <constant>null</constant>.
		  Can be used to ensure a vector is a column vector.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MakeRowVector"/>MakeRowVector</term>
         <listitem>
          <synopsis lang="en">MakeRowVector (A)</synopsis>
	  <para lang="en">Make row vector out of matrix by putting rows one after another.
		  Returns <constant>null</constant> when given <constant>null</constant>.
	          Can be used to ensure a vector is a row vector.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MatrixProduct"/>MatrixProduct</term>
         <listitem>
          <synopsis>MatrixProduct (A)</synopsis>
          <para>Calcule et renvoie le produit de tous les éléments d'une matrice ou d'un vecteur.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MatrixSum"/>MatrixSum</term>
         <listitem>
          <synopsis>MatrixSum (A)</synopsis>
          <para>Calcule et renvoie la somme de tous les éléments d'une matrice ou d'un vecteur.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MatrixSumSquares"/>MatrixSumSquares</term>
         <listitem>
          <synopsis>MatrixSumSquares (A)</synopsis>
          <para>Calcule la somme du carré de tous les éléments d'une matrice ou d'un vecteur.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NonzeroColumns"/>NonzeroColumns</term>
         <listitem>
          <synopsis lang="en">NonzeroColumns (M)</synopsis>
          <para lang="en">Returns a row vector of the indices of nonzero columns in the matrix <varname>M</varname>.</para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NonzeroElements"/>NonzeroElements</term>
         <listitem>
          <synopsis lang="en">NonzeroElements (v)</synopsis>
          <para lang="en">Returns a row vector of the indices of nonzero elements in the vector <varname>v</varname>.</para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-OuterProduct"/>OuterProduct</term>
         <listitem>
          <synopsis>OuterProduct (u,v)</synopsis>
          <para>Retourne le produit tensoriel de deux vecteurs, c'est-à-dire que si on suppose que <varname>u</varname> et <varname>v</varname> sont des vecteurs colonnes, alors le produit tensoriel est <userinput>v * u.'</userinput>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ReverseVector"/>ReverseVector</term>
         <listitem>
          <synopsis>ReverseVector (v)</synopsis>
	  <para>Inverse l'ordre des éléments d'un vecteur. Renvoie <constant>null</constant> si <constant>null</constant> est fourni</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RowSum"/>RowSum</term>
         <listitem>
          <synopsis>RowSum (m)</synopsis>
          <para>Calcule la somme pour chaque ligne d'une matrice et renvoie un vecteur colonne contenant le résultat.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RowSumSquares"/>RowSumSquares</term>
         <listitem>
          <synopsis>RowSumSquares (m)</synopsis>
          <para lang="en">Calculate sum of squares of each row in a matrix and return a vertical vector with the results.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RowsOf"/>RowsOf</term>
         <listitem>
          <synopsis>RowsOf (M)</synopsis>
	  <para lang="en">Gets the rows of a matrix as a vertical vector.  Each element
of the vector is a horizontal vector that is the corresponding row of
<varname>M</varname>.  This function is useful if you wish to loop over the
rows of a matrix.  For example, as <userinput>for r in RowsOf(M) do
something(r)</userinput>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SetMatrixSize"/>SetMatrixSize</term>
         <listitem>
          <synopsis>SetMatrixSize (M,lignes,colonnes)</synopsis>
          <para lang="en">Make new matrix of given size from old one.  That is, a new
	  matrix will be returned to which the old one is copied.  Entries that
	  don't fit are clipped and extra space is filled with zeros.
	  If <varname>rows</varname> or <varname>columns</varname> are zero
	  then <constant>null</constant> is returned.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ShuffleVector"/>ShuffleVector</term>
         <listitem>
          <synopsis>ShuffleVector (v)</synopsis>
	  <para lang="en">Shuffle elements in a vector.  Return <constant>null</constant> if given <constant>null</constant>.</para>
	  <para lang="en">Version 1.0.13 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SortVector"/>SortVector</term>
         <listitem>
          <synopsis>SortVector (v)</synopsis>
          <para>Trie les éléments d'un vecteur en ordre croissant.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-StripZeroColumns"/>StripZeroColumns</term>
         <listitem>
          <synopsis>StripZeroColumns (M)</synopsis>
          <para>Élimine toutes les colonnes entièrement nulles de <varname>M</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-StripZeroRows"/>StripZeroRows</term>
         <listitem>
          <synopsis>StripZeroRows (M)</synopsis>
          <para>Élimine toutes les lignes entièrement nulles de <varname>M</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Submatrix"/>Submatrix</term>
         <listitem>
          <synopsis>Submatrix (m,r,c)</synopsis>
          <para>Renvoie certaines colonnes et lignes d'une matrice. C'est équivalent à <userinput>m@(r,c)</userinput>. <varname>r</varname> et <varname>c</varname> doivent être des vecteurs de lignes et de colonnes (ou de simples nombres si vous avez besoin d'une seule ligne ou colonne).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SwapRows"/>SwapRows</term>
         <listitem>
          <synopsis>SwapRows (m,ligne1,ligne2)</synopsis>
          <para>Échange deux lignes dans une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-UpperTriangular"/>UpperTriangular</term>
         <listitem>
          <synopsis>UpperTriangular (M)</synopsis>
          <para>Renvoie une copie de la matrice <varname>M</varname> avec tous les éléments sous la diagonale mis à zéro.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-columns"/>columns</term>
         <listitem>
          <synopsis>columns (M)</synopsis>
          <para>Renvoie le nombre de colonnes d'une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-elements"/>elements</term>
         <listitem>
          <synopsis>elements (M)</synopsis>
          <para>Renvoie le nombre total d'éléments d'une matrice. C'est le nombre de colonnes multiplié par le nombre de lignes.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ones"/>ones</term>
         <listitem>
          <synopsis>ones (lignes,colonnes...)</synopsis>
	  <para>Crée une matrice de 1 (ou un vecteur colonne si un seul argument est donné). Renvoie <constant>null</constant> si ligne ou colonne est nul.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-rows"/>rows</term>
         <listitem>
          <synopsis>rows (M)</synopsis>
          <para>Renvoie le nombre de lignes d'une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-zeros"/>zeros</term>
         <listitem>
          <synopsis>zeros (lignes,colonnes...)</synopsis>
	  <para>Crée une matrice de 0 (ou un vecteur colonne si un seul argument est donné). Renvoie <constant>null</constant> si ligne ou colonne est nul.</para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-linear-algebra">
      <title>Algèbre linéaire</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-AuxiliaryUnitMatrix"/>AuxiliaryUnitMatrix</term>
         <listitem>
          <synopsis>AuxiliaryUnitMatrix (n)</synopsis>
          <para lang="en">Get the auxiliary unit matrix of size <varname>n</varname>.  This is a square matrix with that is all zero except the
superdiagonal being all ones.  It is the Jordan block matrix of one zero eigenvalue.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/JordanCanonicalFormTheorem">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/JordanBlock.html">Mathworld</ulink> for more information on Jordan Canonical Form.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BilinearForm"/>BilinearForm</term>
         <listitem>
          <synopsis>BilinearForm (v,A,w)</synopsis>
          <para>Évalue (v,w) par rapport à la forme bilinéaire donnée par la matrice A.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BilinearFormFunction"/>BilinearFormFunction</term>
         <listitem>
          <synopsis>BilinearFormFunction (A)</synopsis>
          <para>Renvoie une fonction qui évalue deux vecteurs par rapport à la forme bilinéaire donnée par A.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CharacteristicPolynomial"/>CharacteristicPolynomial</term>
         <listitem>
          <synopsis>CharacteristicPolynomial (M)</synopsis>
          <para>Alias : <function>CharPoly</function></para>
	  <para>Renvoie le polynôme caractéristique d'un vecteur. C'est-à-dire renvoie les coefficients du polynôme en commençant par le terme constant. Ce polynôme est défini par <userinput>det(M-xI)</userinput>. Les racines de ce polynôme sont les valeurs propres de <varname>M</varname>. Consultez également <link linkend="gel-function-CharacteristicPolynomialFunction">CharacteristicPolynomialFunction</link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Characteristic_polynomial">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/CharacteristicEquation">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CharacteristicPolynomialFunction"/>CharacteristicPolynomialFunction</term>
         <listitem>
          <synopsis>CharacteristicPolynomialFunction (M)</synopsis>
	  <para>Renvoie le polynôme caractéristique d'un vecteur sous la forme d'une fonction. Ce polynôme est défini par <userinput>det(M-xI)</userinput>. Les racines de ce polynôme sont les valeurs propres de <varname>M</varname>. Consultez également <link linkend="gel-function-CharacteristicPolynomial">CharacteristicPolynomial</link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Characteristic_polynomial">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/CharacteristicEquation">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ColumnSpace"/>ColumnSpace</term>
         <listitem>
          <synopsis>ColumnSpace (M)</synopsis>
	  <para>Renvoie une matrice de base pour le sous-espace vectoriel d'une matrice. C'est-à-dire renvoie une matrice dont les colonnes forment une base pour le sous-espace vectoriel de <varname>M</varname>, donc l'espace engendré par les colonnes de <varname>M</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Row_and_column_spaces">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CommutationMatrix"/>CommutationMatrix</term>
         <listitem>
          <synopsis>CommutationMatrix (m, n)</synopsis>
	  <para lang="en">Return the commutation matrix <userinput>K(m,n)</userinput>, which is the unique <userinput>m*n</userinput> by
		  <userinput>m*n</userinput> matrix such that <userinput>K(m,n) * MakeVector(A) = MakeVector(A.')</userinput> for all <varname>m</varname> by <varname>n</varname>
		  matrices <varname>A</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CompanionMatrix"/>CompanionMatrix</term>
         <listitem>
          <synopsis>CompanionMatrix (p)</synopsis>
          <para>Matrice compagnon d'un polynôme (comme vecteur).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ConjugateTranspose"/>ConjugateTranspose</term>
         <listitem>
          <synopsis>ConjugateTranspose (M)</synopsis>
          <para>Transposée conjuguée d'une matrice (matrice adjointe). Identique à l'opérateur <userinput>'</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Conjugate_transpose">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/ConjugateTranspose">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Convolution"/>Convolution</term>
         <listitem>
          <synopsis>Convolution (a,b)</synopsis>
          <para>Alias : <function>convol</function></para>
          <para>Calcule la convolution de deux vecteurs horizontaux.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ConvolutionVector"/>ConvolutionVector</term>
         <listitem>
          <synopsis>ConvolutionVector (a,b)</synopsis>
          <para>Calcule la convolution de deux vecteurs horizontaux. Renvoie le résultat sous la forme d'un vecteur dont les composants ne sont pas additionnées ensemble.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CrossProduct"/>CrossProduct</term>
         <listitem>
          <synopsis>CrossProduct (v,w)</synopsis>
	  <para>Produit vectoriel de deux vecteurs dans R<superscript>3</superscript> sous la forme d'un vecteur colonne.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Cross_product">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DeterminantalDivisorsInteger"/>DeterminantalDivisorsInteger</term>
         <listitem>
          <synopsis>DeterminantalDivisorsInteger (M)</synopsis>
          <para lang="en">Get the determinantal divisors of an integer matrix.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DirectSum"/>DirectSum</term>
         <listitem>
          <synopsis>DirectSum (M,N...)</synopsis>
          <para>Somme directe de matrices.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Matrix_addition#directsum">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DirectSumMatrixVector"/>DirectSumMatrixVector</term>
         <listitem>
          <synopsis>DirectSumMatrixVector (v)</synopsis>
          <para>Somme directe d'un vecteur de matrices.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Matrix_addition#directsum">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Eigenvalues"/>Eigenvalues</term>
         <listitem>
          <synopsis>Eigenvalues (M)</synopsis>
          <para>Alias : <function>eig</function></para>
          <para>Renvoie les valeurs propres d'une matrice carrée. Ne fonctionne actuellement que pour les matrices de taille inférieure ou égale à 4 par 4 ou pour les matrices triangulaires (pour lesquelles les valeurs propres sont sur la diagonale).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Eigenvalue">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/Eigenvalue">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/Eigenvalue.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Eigenvectors"/>Eigenvectors</term>
         <listitem>
          <synopsis>Eigenvectors (M)</synopsis>
          <synopsis>Eigenvectors (M, &amp;valeurspropres)</synopsis>
          <synopsis>Eigenvectors (M, &amp;valeurpropres, &amp;multiplicités)</synopsis>
	  <para>Renvoie les vecteurs propres d'une matrice carrée. Il est possible en option d'obtenir les valeurs propres ainsi que leur multiplicité algébrique. Ne fonctionne actuellement que pour les matrices 2x2.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Eigenvector">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/Eigenvector">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/Eigenvector.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-GramSchmidt"/>GramSchmidt</term>
         <listitem>
          <synopsis>GramSchmidt (v,B...)</synopsis>
	  <para>Applique le procédé de Gram-Schmidt (aux colonnes) par rapport au produit scalaire donné par <varname>B</varname>. Si <varname>B</varname> n'est pas fourni alors le produit hermitien standard est utilisé. <varname>B</varname> peut être soit une forme sesquilinéaire à deux arguments soit une matrice fournissant une forme sesquilinéaire. Les vecteurs seront orthogonaux par rapport à <varname>B</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Gram%E2%80%93Schmidt_process">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/GramSchmidtOrthogonalization">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-HankelMatrix"/>HankelMatrix</term>
         <listitem>
          <synopsis>HankelMatrix (c,r)</synopsis>
	  <para lang="en">Hankel matrix, a matrix whose skew-diagonals are constant.  <varname>c</varname> is the first row and <varname>r</varname> is the
		  last column.  It is assumed that both arguments are vectors and the last element of <varname>c</varname> is the same
		  as the first element of <varname>r</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hankel_matrix">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-HilbertMatrix"/>HilbertMatrix</term>
         <listitem>
          <synopsis>HilbertMatrix (n)</synopsis>
          <para>Matrice de Hilbert d'ordre <varname>n</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hilbert_matrix">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HilbertMatrix">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Image"/>Image</term>
         <listitem>
          <synopsis>Image (T)</synopsis>
          <para>Renvoie l'image (espace vectoriel engendré par les colonnes) d'une transformation linéaire.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Row_and_column_spaces">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-InfNorm"/>InfNorm</term>
         <listitem>
          <synopsis>InfNorm (v)</synopsis>
          <para>Renvoie la norme « infini », appelée aussi norme sup, ou encore norme de la convergence uniforme.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-InvariantFactorsInteger"/>InvariantFactorsInteger</term>
         <listitem>
          <synopsis>InvariantFactorsInteger (M)</synopsis>
          <para lang="en">Get the invariant factors of a square integer matrix.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-InverseHilbertMatrix"/>InverseHilbertMatrix</term>
         <listitem>
          <synopsis>InverseHilbertMatrix (n)</synopsis>
          <para>Matrice inverse de Hilbert d'ordre <varname>n</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hilbert_matrix">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HilbertMatrix">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsHermitian"/>IsHermitian</term>
         <listitem>
          <synopsis>IsHermitian (M)</synopsis>
          <para>Indique si une matrice est hermitienne. C'est-à-dire si elle est égale à sa transposée conjuguée.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hermitian_matrix">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/HermitianMatrix">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsInSubspace"/>IsInSubspace</term>
         <listitem>
          <synopsis>IsInSubspace (v,W)</synopsis>
          <para>Teste si un vecteur appartient à un sous-espace.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsInvertible"/>IsInvertible</term>
         <listitem>
          <synopsis>IsInvertible (n)</synopsis>
          <para lang="en">Is a matrix (or number) invertible (Integer matrix is invertible if and only if it is invertible over the integers).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsInvertibleField"/>IsInvertibleField</term>
         <listitem>
          <synopsis>IsInvertibleField (n)</synopsis>
          <para>Indique si une matrice (ou un nombre) est inversible sur un corps.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsNormal"/>IsNormal</term>
         <listitem>
          <synopsis>IsNormal (M)</synopsis>
          <para>Indique si <varname>M</varname> est une matrice normale, c'est-à-dire <userinput>M*M' == M'*M</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/NormalMatrix">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/NormalMatrix.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPositiveDefinite"/>IsPositiveDefinite</term>
         <listitem>
          <synopsis>IsPositiveDefinite (M)</synopsis>
          <para>Indique si <varname>M</varname> est une matrice hermitienne définie positive. C'est-à-dire si <userinput>HermitianProduct(M*v,v)</userinput> est toujours strictement positif pour tout vecteur <varname>v</varname>. <varname>M</varname> doit être carré et hermitienne pour être définie positive. Le contrôle effectué est que le déterminant de chaque sous-matrice principale n'est pas négatif (consultez <link linkend="gel-function-HermitianProduct">HermitianProduct</link>).</para>
	  <para>Notez que certains auteurs (par exemple Mathworld) n'exigent pas que <varname>M</varname> soit hermitienne, ainsi la condition porte sur la partie réelle du produit scalaire mais ce n'est pas le cas de Genius. Si vous souhaitez réaliser ce type de contrôle, vérifiez seulement la partie hermitienne de la matrice <varname>M</varname> comme ceci : <userinput>IsPositiveDefinite(M+M')</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Positive-definite_matrix">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/PositiveDefinite">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/PositiveDefiniteMatrix.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPositiveSemidefinite"/>IsPositiveSemidefinite</term>
         <listitem>
          <synopsis>IsPositiveSemidefinite (M)</synopsis>
          <para>Indique si <varname>M</varname> est une matrice hermitienne semi-définie positive. C'est-à-dire si <userinput>HermitianProduct(M*v,v)</userinput> est toujours non négatif pour tout vecteur <varname>v</varname>. <varname>M</varname> doit être carré et hermitienne pour être semi-définie positive. Le contrôle effectué est que le déterminant de chaque sous-matrice principale n'est pas négatif (consultez <link linkend="gel-function-HermitianProduct">HermitianProduct</link>).</para>
	  <para>Notez que certains auteurs n'exigent pas que <varname>M</varname> soit hermitienne, ainsi la condition porte sur la partie réelle du produit scalaire mais ce n'est pas le cas de Genius. Si vous souhaitez réaliser ce type de contrôle, vérifiez seulement la partie hermitienne de la matrice <varname>M</varname> comme ceci : <userinput>IsPositiveSemiDefinite(M+M')</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/PositiveSemidefinite">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/PositiveSemidefiniteMatrix.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsSkewHermitian"/>IsSkewHermitian</term>
         <listitem>
          <synopsis>IsSkewHermitian (M)</synopsis>
          <para>Indique si une matrice est anti-hermitienne. C'est-à-dire si sa transposée conjuguée est égale à l'opposée de la matrice.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/SkewHermitianMatrix">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsUnitary"/>IsUnitary</term>
         <listitem>
          <synopsis>IsUnitary (M)</synopsis>
          <para>Indique si une matrice est unitaire. C'est-à-dire si <userinput>M'*M</userinput> et <userinput>M*M'</userinput> sont égaux à l'identité.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/UnitaryTransformation">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/UnitaryMatrix.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-JordanBlock"/>JordanBlock</term>
         <listitem>
          <synopsis>JordanBlock (n,lambda)</synopsis>
          <para>Alias : <function>J</function></para>
          <para>Renvoie le bloc de Jordan correspondant à la valeur propre <varname>lambda</varname> de multiplicité <varname>n</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/JordanCanonicalFormTheorem">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/JordanBlock.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Kernel"/>Kernel</term>
         <listitem>
          <synopsis>Kernel (T)</synopsis>
          <para>Renvoie le noyau d'une transformation linéaire.</para>
	  <para>(consultez <link linkend="gel-function-NullSpace">NullSpace</link>)</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-KroneckerProduct"/>KroneckerProduct</term>
         <listitem>
          <synopsis lang="en">KroneckerProduct (M, N)</synopsis>
          <para lang="en">Aliases: <function>TensorProduct</function></para>
	  <para lang="en">
		  Compute the Kronecker product (tensor product in standard basis)
		  of two matrices.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Kronecker_product">Wikipedia</ulink>, 
	    <ulink url="http://planetmath.org/KroneckerProduct">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/KroneckerProduct.html">Mathworld</ulink> for more information.
          </para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><anchor id="gel-function-LUDecomposition"/>LUDecomposition</term>
         <listitem>
          <synopsis>LUDecomposition (A, L, U)</synopsis>
          <para lang="en">
		  Get the LU decomposition of <varname>A</varname>, that is
		  find a lower triangular matrix and upper triangular
		  matrix whose product is <varname>A</varname>.
	    Store the result in the <varname>L</varname> and
	    <varname>U</varname>, which should be references.  It returns <constant>true</constant>
	    if successful.
	    For example suppose that A is a square matrix, then after running:
	    <screen lang="en"><prompt>genius&gt;</prompt> <userinput>LUDecomposition(A,&amp;L,&amp;U)</userinput>
</screen>
	    You will have the lower matrix stored in a variable called
	    <varname>L</varname> and the upper matrix in a variable called
	    <varname>U</varname>.
	  </para>
	  <para lang="en">
	    This is the LU decomposition of a matrix aka Crout and/or Cholesky
	    reduction.
	    (ISBN 0-201-11577-8 pp.99-103)
	    The upper triangular matrix features a diagonal
	    of values 1 (one).  This is not Doolittle's Method, which features
	    the 1's diagonal on the lower matrix. 
	  </para>
	  <para>Toutes les matrices ne possèdent pas de décomposition LU, par exemple <userinput>[0,1;1,0]</userinput> n'en a pas. Dans ce cas, cette fonction renvoie <constant>false</constant> (faux) et initialise <varname>L</varname> et <varname>U</varname> à <constant>null</constant>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/LU_decomposition">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/LUDecomposition">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/LUDecomposition.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Minor"/>Minor</term>
         <listitem>
          <synopsis>Minor (M,i,j)</synopsis>
          <para>Renvoie le mineur <varname>i</varname>-<varname>j</varname> d'une matrice.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/Minor">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NonPivotColumns"/>NonPivotColumns</term>
         <listitem>
          <synopsis>NonPivotColumns (M)</synopsis>
          <para>Renvoie les colonnes qui ne sont pas les colonnes pivot d'une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Norm"/>Norm</term>
         <listitem>
          <synopsis>Norm (v,p...)</synopsis>
          <para>Alias : <function>norm</function></para>
          <para>Renvoie la norme-p d'un vecteur (ou norme-2 si p n'est pas fourni).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NullSpace"/>NullSpace</term>
         <listitem>
          <synopsis>NullSpace (T)</synopsis>
          <para>Renvoie le noyau d'une matrice. C'est-à-dire le noyau de l'application linéaire que la matrice représente sous la forme d'une matrice dont l'espace des colonnes est le noyau de <varname>T</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/Nullspace">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Nullity"/>Nullity</term>
         <listitem>
          <synopsis>Nullity (M)</synopsis>
          <para>Alias : <function>nullity</function></para>
          <para>Renvoie la dimension du noyau de la matrice <varname>M</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/Nullity">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-OrthogonalComplement"/>OrthogonalComplement</term>
         <listitem>
          <synopsis>OrthogonalComplement (M)</synopsis>
          <para>Renvoie le complément orthogonal de l'espace des colonnes.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PivotColumns"/>PivotColumns</term>
         <listitem>
          <synopsis>PivotColumns (M)</synopsis>
          <para lang="en">Return pivot columns of a matrix, that is columns that have a leading 1 in row reduced form.  Also returns the row where they occur.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Projection"/>Projection</term>
         <listitem>
          <synopsis>Projection (v,W,B...)</synopsis>
	  <para>Projection du vecteur <varname>v</varname> sur le sous-espace <varname>W</varname> par rapport au produit scalaire donné par <varname>B</varname>. Si <varname>B</varname> n'est pas fourni alors le produit hermitien standard est utilisé. <varname>B</varname> peut être soit une forme sesquilinéaire à deux arguments soit une matrice fournissant une forme sesquilinéaire.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-QRDecomposition"/>QRDecomposition</term>
         <listitem>
          <synopsis>QRDecomposition (A, Q)</synopsis>
          <para lang="en">
	    Get the QR decomposition of a square matrix <varname>A</varname>,
	    returns the upper triangular matrix <varname>R</varname>
	    and sets <varname>Q</varname> to the orthogonal (unitary) matrix.
	    <varname>Q</varname> should be a reference or <constant>null</constant> if you don't
	    want any return.
	    For example:
	    <screen lang="en"><prompt>genius&gt;</prompt> <userinput>R = QRDecomposition(A,&amp;Q)</userinput>
</screen>
	    You will have the upper triangular matrix stored in
	    a variable called
	    <varname>R</varname> and the orthogonal (unitary) matrix stored in
	    <varname>Q</varname>.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/QR_decomposition">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/QRDecomposition">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/QRDecomposition.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RayleighQuotient"/>RayleighQuotient</term>
         <listitem>
          <synopsis>RayleighQuotient (A,x)</synopsis>
          <para>Renvoie le quotient de Rayleigh (aussi appelé le quotient ou rapport de Rayleigh-Ritz) d'une matrice et d'un vecteur.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/RayleighQuotient">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RayleighQuotientIteration"/>RayleighQuotientIteration</term>
         <listitem>
          <synopsis>RayleighQuotientIteration (A,x,epsilon,maxiter,vecref)</synopsis>
          <para>Cherche les valeurs propres de <varname>A</varname> en utilisant la méthode itérative du quotient de Rayleigh. <varname>x</varname> est une valeur initiale estimée pour un vecteur propre et peut être tirée au hasard. Si vous voulez avoir une chance de trouver des valeurs propres complexes, la partie imaginaire ne doit pas être nulle. Le programme effectue au maximum <varname>maxiter</varname> itérations et renvoie <constant>null</constant> s'il ne peut trouver une solution avec une précision inférieure à <varname>epsilon</varname>. <varname>vecref</varname> doit être soit <constant>null</constant> ou une référence à une variable dans laquelle le vecteur propre est enregistré.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/RayleighQuotient">Planetmath</ulink> for more information on Rayleigh quotient.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Rank"/>Rank</term>
         <listitem>
          <synopsis>Rank (M)</synopsis>
          <para>Alias : <function>rank</function></para>
          <para>Renvoie le rang d'une matrice.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/SylvestersLaw">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RosserMatrix"/>RosserMatrix</term>
         <listitem>
          <synopsis>RosserMatrix ()</synopsis>
          <para lang="en">Returns the Rosser matrix, which is a classic symmetric eigenvalue test problem.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Rotation2D"/>Rotation2D</term>
         <listitem>
          <synopsis>Rotation2D (angle)</synopsis>
          <para>Alias : <function>RotationMatrix</function></para>
          <para>Renvoie la matrice correspondant à la rotation centrée sur l'origine dans R<superscript>2</superscript>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Rotation3DX"/>Rotation3DX</term>
         <listitem>
          <synopsis>Rotation3DX (angle)</synopsis>
          <para>Renvoie la matrice correspondant à la rotation centrée sur l'origine dans R<superscript>3</superscript> autour de l'axe des x.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Rotation3DY"/>Rotation3DY</term>
         <listitem>
          <synopsis>Rotation3DY (angle)</synopsis>
          <para>Renvoie la matrice correspondant à la rotation centrée sur l'origine dans R<superscript>3</superscript> autour de l'axe des y.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Rotation3DZ"/>Rotation3DZ</term>
         <listitem>
          <synopsis>Rotation3DZ (angle)</synopsis>
          <para>Renvoie la matrice correspondant à la rotation centrée sur l'origine dans R<superscript>3</superscript> autour de l'axe des z.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RowSpace"/>RowSpace</term>
         <listitem>
          <synopsis>RowSpace (M)</synopsis>
          <para>Renvoie une matrice de base pour l'espace vectoriel engendré par les lignes d'une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SesquilinearForm"/>SesquilinearForm</term>
         <listitem>
          <synopsis>SesquilinearForm (v,A,w)</synopsis>
          <para>Évalue (v, w) par rapport à la forme sesquilinéaire donnée par la matrice A.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SesquilinearFormFunction"/>SesquilinearFormFunction</term>
         <listitem>
          <synopsis>SesquilinearFormFunction (A)</synopsis>
          <para>Renvoie une fonction qui évalue deux vecteurs par rapport à la forme sesquilinéaire donnée par A.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SmithNormalFormField"/>SmithNormalFormField</term>
         <listitem>
          <synopsis>SmithNormalFormField (A)</synopsis>
          <para lang="en">Returns the Smith normal form of a matrix over fields (will end up with 1's on the diagonal).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Smith_normal_form">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SmithNormalFormInteger"/>SmithNormalFormInteger</term>
         <listitem>
          <synopsis>SmithNormalFormInteger (M)</synopsis>
          <para lang="en">Return the Smith normal form for square integer matrices over integers.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Smith_normal_form">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SolveLinearSystem"/>SolveLinearSystem</term>
         <listitem>
          <synopsis>SolveLinearSystem (M,V,params...)</synopsis>
	  <para>Résout le système linéaire Mx=V, renvoie V s'il y a une solution unique ou <constant>null</constant> sinon. Deux références d'arguments supplémentaires peuvent être utilisés pour recevoir les réductions de M et V.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ToeplitzMatrix"/>ToeplitzMatrix</term>
         <listitem>
          <synopsis>ToeplitzMatrix (c, r...)</synopsis>
	  <para lang="en">Return the Toeplitz matrix constructed given the first column c
and (optionally) the first row r.  If only the column c is given then it is
conjugated and the nonconjugated version is used for the first row to give a
Hermitian matrix (if the first element is real).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Toeplitz_matrix">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/ToeplitzMatrix">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Trace"/>Trace</term>
         <listitem>
          <synopsis>Trace (M)</synopsis>
          <para>Alias : <function>trace</function></para>
          <para>Calcule la trace d'une matrice, c'est-à-dire la somme des éléments diagonaux.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Trace_(linear_algebra)">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/Trace">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Transpose"/>Transpose</term>
         <listitem>
          <synopsis>Transpose (M)</synopsis>
          <para>Matrice transposée. C'est identique à l'opérateur <userinput>.'</userinput></para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Transpose">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/Transpose">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VandermondeMatrix"/>VandermondeMatrix</term>
         <listitem>
          <synopsis>VandermondeMatrix (v)</synopsis>
          <para>Alias : <function>vander</function></para>
          <para>Renvoie la matrice de Vandermonde.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Vandermonde_matrix">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorAngle"/>VectorAngle</term>
         <listitem>
          <synopsis>VectorAngle (v,w,B...)</synopsis>
          <para>L'angle entre deux vecteurs par rapport au produit scalaire donné par <varname>B</varname>. Si <varname>B</varname> n'est pas fourni alors le produit hermitien standard est utilisé. <varname>B</varname> peut être soit une forme sesquilinéaire à deux arguments soit une matrice fournissant une forme sesquilinéaire.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorSpaceDirectSum"/>VectorSpaceDirectSum</term>
         <listitem>
          <synopsis>VectorSpaceDirectSum (M,N)</synopsis>
          <para>Somme directe des espaces vectoriels M et N.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorSubspaceIntersection"/>VectorSubspaceIntersection</term>
         <listitem>
          <synopsis>VectorSubspaceIntersection (M,N)</synopsis>
          <para>Intersection des sous-espaces donnés par M et N.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorSubspaceSum"/>VectorSubspaceSum</term>
         <listitem>
          <synopsis>VectorSubspaceSum (M,N)</synopsis>
          <para>Somme des espaces vectoriels M et N, c'est-à-dire {w | w=m+n, m dans M, n dans N}.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-adj"/>adj</term>
         <listitem>
          <synopsis>adj (m)</synopsis>
          <para>Alias : <function>Adjugate</function></para>
          <para>Renvoie la matrice adjointe d'une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-cref"/>cref</term>
         <listitem>
          <synopsis>cref (M)</synopsis>
          <para lang="en">Aliases: <function>CREF</function> <function>ColumnReducedEchelonForm</function></para>
          <para>Calcule la forme échelonnée réduite en colonnes.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-det"/>det</term>
         <listitem>
          <synopsis>det (M)</synopsis>
          <para>Alias : <function>Determinant</function></para>
          <para>Renvoie le déterminant d'une matrice.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Determinant">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/Determinant2">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ref"/>ref</term>
         <listitem>
          <synopsis>ref (M)</synopsis>
          <para lang="en">Aliases: <function>REF</function> <function>RowEchelonForm</function></para>
	  <para>Renvoie la matrice échelonnée en lignes (row echelon) d'une matrice. C'est-à-dire effectue une élimination de Gauss de <varname>M</varname>. Les lignes de pivot sont divisées pour que tous les pivots soient égaux à 1.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Row_echelon_form">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/RowEchelonForm">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-rref"/>rref</term>
         <listitem>
          <synopsis>rref (M)</synopsis>
          <para lang="en">Aliases: <function>RREF</function> <function>ReducedRowEchelonForm</function></para>
          <para>Renvoie la matrice échelonnée réduite en lignes (reduced row echelon) d'une matrice. C'est-à-dire effectue une élimination de Gauss-Jordan de <varname>M</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Reduced_row_echelon_form">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/ReducedRowEchelonForm">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-combinatorics">
      <title>Combinatoire</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-Catalan"/>Catalan</term>
         <listitem>
          <synopsis>Catalan (n)</synopsis>
          <para>Renvoie le <varname>n</varname>-ième nombre catalan.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/CatalanNumbers">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Combinations"/>Combinations</term>
         <listitem>
          <synopsis>Combinations (k,n)</synopsis>
          <para>Renvoie toutes les combinaisons de k nombres de 1 à n comme un vecteur de vecteurs (consultez aussi <link linkend="gel-function-NextCombination">NextCombination</link>).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Combination">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DoubleFactorial"/>DoubleFactorial</term>
         <listitem>
          <synopsis>DoubleFactorial (n)</synopsis>
          <para>Double factorielle : <userinput>n(n-2)(n-4)...</userinput></para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/DoubleFactorial">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Factorial"/>Factorial</term>
         <listitem>
          <synopsis>Factorial (n)</synopsis>
          <para>Factorielle : <userinput>n(n-1)(n-2)...</userinput></para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/Factorial">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FallingFactorial"/>FallingFactorial</term>
         <listitem>
          <synopsis>FallingFactorial (n,k)</synopsis>
          <para>Factorielle décroissante : <userinput>(n)_k·=·n(n-1)...(n-(k-1))</userinput></para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/FallingFactorial">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Fibonacci"/>Fibonacci</term>
         <listitem>
          <synopsis>Fibonacci (x)</synopsis>
          <para>Alias : <function>fib</function></para>
          <para>Calcule le <varname>n</varname>-ième nombre de Fibonacci. C'est-à-dire le nombre défini de manière récursive par <userinput>Fibonacci(n) = Fibonacci(n-1) + Fibonacci(n-2)</userinput> et <userinput>Fibonacci(1) = Fibonacci(2) = 1</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fibonacci_number">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/FibonacciSequence">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FibonacciNumber.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FrobeniusNumber"/>FrobeniusNumber</term>
         <listitem>
          <synopsis>FrobeniusNumber (v,param...)</synopsis>
          <para lang="en">
	    Calculate the Frobenius number.  That is calculate largest
	    number that cannot be given as a non-negative integer linear
	    combination of a given vector of non-negative integers.
	    The vector can be given as separate numbers or a single vector.
	    All the numbers given should have GCD of 1.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Coin_problem">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FrobeniusNumber.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-GaloisMatrix"/>GaloisMatrix</term>
         <listitem>
          <synopsis>GaloisMatrix (règle_de_combinaison)</synopsis>
          <para lang="en">Galois matrix given a linear combining rule (a_1*x_1+...+a_n*x_n=x_(n+1)).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-GreedyAlgorithm"/>GreedyAlgorithm</term>
         <listitem>
          <synopsis lang="en">GreedyAlgorithm (n,v)</synopsis>
          <para>Trouve le vecteur <varname>c</varname> d'entiers non négatifs tel que le produit scalaire par <varname>v</varname> est égal à n. Si ce n'est pas possible, renvoie <constant>null</constant>. <varname>v</varname> doit être fourni trié dans l'ordre croissant et doit être composé d'entier non négatif.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Greedy_algorithm">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/GreedyAlgorithm.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-HarmonicNumber"/>HarmonicNumber</term>
         <listitem>
          <synopsis>HarmonicNumber (n,r)</synopsis>
          <para>Alias : <function>HarmonicH</function></para>
	  <para lang="en">Harmonic Number, the <varname>n</varname>th harmonic number of order <varname>r</varname>.
	        That is, it is the sum of <userinput>1/k^r</userinput> for <varname>k</varname>
		from 1 to n.  Equivalent to <userinput>sum k = 1 to n do 1/k^r</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Harmonic_number">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Hofstadter"/>Hofstadter</term>
         <listitem>
          <synopsis>Hofstadter (n)</synopsis>
          <para>Fonction de Hofstadter q(n) définie par q(1)=1, q(2)=1, q(n)=q(n-q(n-1))+q(n-q(n-2)).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Hofstadter_sequence">Wikipedia</ulink> for more information.
	    The sequence is <ulink url="https://oeis.org/A005185">A005185 in OEIS</ulink>.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinearRecursiveSequence"/>LinearRecursiveSequence</term>
         <listitem>
          <synopsis>LinearRecursiveSequence (valeurs_ensemencement,règle_de_combinaison,n)</synopsis>
          <para>Calcule la relation de récurrence linéaire en utilisant l'algorithme de Galois.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Multinomial"/>Multinomial</term>
         <listitem>
          <synopsis>Multinomial (v,param...)</synopsis>
          <para>Calcule les coefficients multinomiaux. Prend un vecteur de <varname>k</varname> entiers non négatifs et calcule les coefficients multinomiaux. Cela correspond aux coefficients dans le polynôme homogène à <varname>k</varname> variables avec les puissances correspondantes.</para>
	  <para lang="en">
	    The formula for <userinput>Multinomial(a,b,c)</userinput>
	    can be written as:
<programlisting lang="en">(a+b+c)! / (a!b!c!)
</programlisting>
	    In other words, if we would have only two elements, then
<userinput>Multinomial(a,b)</userinput> is the same thing as
<userinput>Binomial(a+b,a)</userinput> or
<userinput>Binomial(a+b,b)</userinput>.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Multinomial_theorem">Wikipedia</ulink>,
	    <ulink url="http://planetmath.org/MultinomialTheorem">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/MultinomialCoefficient.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NextCombination"/>NextCombination</term>
         <listitem>
          <synopsis>NextCombination (v,n)</synopsis>
	  <para>Calcule la combinaison qui apparaîtrait après v dans un appel à la fonction combinations, la première combinaison devrait être <userinput>[1:k]</userinput>. Cette fonction est utile si vous devez parcourir beaucoup de combinaisons et que vous ne voulez pas gaspiller de la mémoire pour les enregistrer.</para>
	  <para lang="en">
	    For example with Combinations you would normally write a loop like:
          <screen lang="en"><userinput>for n in Combinations (4,6) do (
  SomeFunction (n)
);</userinput>
</screen>
	    But with NextCombination you would write something like:
          <screen lang="en"><userinput>n:=[1:4];
do (
  SomeFunction (n)
) while not IsNull(n:=NextCombination(n,6));</userinput>
</screen>
	  See also <link linkend="gel-function-Combinations">Combinations</link>.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Combination">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Pascal"/>Pascal</term>
         <listitem>
          <synopsis>Pascal (i)</synopsis>
          <para lang="en">Get the Pascal's triangle as a matrix.  This will return
	  an <varname>i</varname>+1 by <varname>i</varname>+1 lower diagonal
	  matrix that is the Pascal's triangle after <varname>i</varname>
	  iterations.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/PascalsTriangle">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Permutations"/>Permutations</term>
         <listitem>
          <synopsis>Permutations (k,n)</synopsis>
          <para>Renvoie toutes les permutations de <varname>k</varname> nombres de 1 à <varname>n</varname> comme un vecteur de vecteurs.</para>
          <para lang="en">
	    See
	    <ulink url="http://mathworld.wolfram.com/Permutation.html">Mathworld</ulink> or
	    <ulink url="https://en.wikipedia.org/wiki/Permutation">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RisingFactorial"/>RisingFactorial</term>
         <listitem>
          <synopsis>RisingFactorial (n,k)</synopsis>
          <para>Alias : <function>Pochhammer</function></para>
          <para>Factorielle croissante (Pochhammer) : (n)_k = n(n+1)...(n+(k-1)).</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/RisingFactorial">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-StirlingNumberFirst"/>StirlingNumberFirst</term>
         <listitem>
          <synopsis>StirlingNumberFirst (n,m)</synopsis>
          <para>Alias : <function>StirlingS1</function></para>
          <para>Nombre de Stirling du premier type.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/StirlingNumbersOfTheFirstKind">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/StirlingNumberoftheFirstKind.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-StirlingNumberSecond"/>StirlingNumberSecond</term>
         <listitem>
          <synopsis>StirlingNumberSecond (n,m)</synopsis>
          <para>Alias : <function>StirlingS2</function></para>
          <para>Nombre de Stirling du second type.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/StirlingNumbersSecondKind">Planetmath</ulink> or
	    <ulink url="http://mathworld.wolfram.com/StirlingNumberoftheSecondKind.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Subfactorial"/>Subfactorial</term>
         <listitem>
          <synopsis>Subfactorial (n)</synopsis>
          <para lang="en">Subfactorial: n! times sum_{k=0}^n (-1)^k/k!.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Triangular"/>Triangular</term>
         <listitem>
          <synopsis>Triangular (nième)</synopsis>
          <para>Calcule le <varname>n</varname>-ième nombre triangulaire.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/TriangularNumbers">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-nCr"/>nCr</term>
         <listitem>
          <synopsis>nCr (n,r)</synopsis>
          <para>Alias : <function>Binomial</function></para>
          <para>Calcule le nombre de combinaisons, c'est-à-dire le coefficient binomial. <varname>n</varname> peut être n'importe quel nombre réel.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/Choose">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-nPr"/>nPr</term>
         <listitem>
          <synopsis>nPr (n,r)</synopsis>
          <para lang="en">Calculate the number of permutations of size
	   <varname>r</varname> of numbers from 1 to <varname>n</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="http://mathworld.wolfram.com/Permutation.html">Mathworld</ulink> or
	    <ulink url="https://en.wikipedia.org/wiki/Permutation">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-calculus">
      <title>Analyse</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-CompositeSimpsonsRule"/>CompositeSimpsonsRule</term>
         <listitem>
          <synopsis>CompositeSimpsonsRule (f,a,b,n)</synopsis>
          <para>Intégration de f par la méthode de Simpson composée sur l'intervalle [a,b] avec n sous-intervalles avec une erreur de l'ordre max(f'''')*h^4*(b-a)/180, notez que n doit être pair.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/SimpsonsRule">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CompositeSimpsonsRuleTolerance"/>CompositeSimpsonsRuleTolerance</term>
         <listitem>
          <synopsis>CompositeSimpsonsRuleTolerance (f,a,b,FourthDerivativeBound,Tolerance)</synopsis>
          <para>Intégration de f par la méthode de Simpson composée sur l'intervalle [a,b] avec un nombre d'étapes calculé à l'aide de la borne de la dérivée quatrième et la tolérance souhaitée.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/SimpsonsRule">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Derivative"/>Derivative</term>
         <listitem>
          <synopsis>Derivative (f,x0)</synopsis>
          <para>Tente de calculer la dérivée en essayant d'abord une approche symbolique puis numérique.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Derivative">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-EvenPeriodicExtension"/>EvenPeriodicExtension</term>
         <listitem>
          <synopsis>EvenPeriodicExtension (f,L)</synopsis>
	  <para lang="en">Return a function that is the even periodic extension of
<function>f</function> with half period <varname>L</varname>.  That
is a function defined on the interval <userinput>[0,L]</userinput>
extended to be even on <userinput>[-L,L]</userinput> and then
extended to be periodic with period <userinput>2*L</userinput>.</para>
	  <para>Consultez aussi <link linkend="gel-function-OddPeriodicExtension">OddPeriodicExtension</link> et <link linkend="gel-function-PeriodicExtension">PeriodicExtension</link>.</para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FourierSeriesFunction"/>FourierSeriesFunction</term>
         <listitem>
          <synopsis>FourierSeriesFunction (a,b,L)</synopsis>
	  <para lang="en">Return a function that is a Fourier series with the
coefficients given by the vectors <varname>a</varname> (sines) and
<varname>b</varname> (cosines).  Note that <userinput>a@(1)</userinput> is
the constant coefficient!  That is, <userinput>a@(n)</userinput> refers to
the term <userinput>cos(x*(n-1)*pi/L)</userinput>, while
<userinput>b@(n)</userinput> refers to the term
<userinput>sin(x*n*pi/L)</userinput>.  Either <varname>a</varname>
or <varname>b</varname> can be <constant>null</constant>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fourier_series">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FourierSeries.html">Mathworld</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-InfiniteProduct"/>InfiniteProduct</term>
         <listitem>
          <synopsis>InfiniteProduct (fonc,début,inc)</synopsis>
          <para>Essaie de calculer un produit infini pour une fonction à un seul argument.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-InfiniteProduct2"/>InfiniteProduct2</term>
         <listitem>
          <synopsis>InfiniteProduct2 (fonc,param,début,inc)</synopsis>
          <para>Essaie de calculer un produit infini pour une fonction à double arguments avec func(arg,n).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-InfiniteSum"/>InfiniteSum</term>
         <listitem>
          <synopsis>InfiniteSum (fonc,début,inc)</synopsis>
          <para>Essaie de calculer une somme infinie pour une fonction à un seul argument.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-InfiniteSum2"/>InfiniteSum2</term>
         <listitem>
          <synopsis>InfiniteSum2 (fonc,param,début,inc)</synopsis>
          <para>Essaie de calculer une somme infinie pour une fonction à double arguments avec func(arg,n).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsContinuous"/>IsContinuous</term>
         <listitem>
          <synopsis>IsContinuous (f,x0)</synopsis>
          <para>Essaie de voir si une fonction à valeur réelle est continue en x0 en calculant la limite en ce point.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsDifferentiable"/>IsDifferentiable</term>
         <listitem>
          <synopsis>IsDifferentiable (f,x0)</synopsis>
          <para>Teste de différentiabilité en approchant les limites gauche et droite et en les comparant.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LeftLimit"/>LeftLimit</term>
         <listitem>
          <synopsis>LeftLimit (f,x0)</synopsis>
          <para>Calcule la limite gauche d'une fonction à valeurs réelles en x0.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Limit"/>Limit</term>
         <listitem>
          <synopsis>Limit (f,x0)</synopsis>
          <para>Calcule la limite d'une fonction à valeur réelle en x0. Essaie de calculer les deux limites à gauche et à droite.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MidpointRule"/>MidpointRule</term>
         <listitem>
          <synopsis>MidpointRule (f,a,b,n)</synopsis>
          <para>Intégration par la méthode des rectangles.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalDerivative"/>NumericalDerivative</term>
         <listitem>
          <synopsis>NumericalDerivative (f,x0)</synopsis>
          <para>Alias : <function>NDerivative</function></para>
          <para>Essaie de calculer la dérivée par méthode numérique.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Derivative">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalFourierSeriesCoefficients"/>NumericalFourierSeriesCoefficients</term>
         <listitem>
          <synopsis>NumericalFourierSeriesCoefficients (f,L,N)</synopsis>
	  <para lang="en">Return a vector of vectors <userinput>[a,b]</userinput>
where <varname>a</varname> are the cosine coefficients and
<varname>b</varname> are the sine coefficients of
the Fourier series of
<function>f</function> with half-period <varname>L</varname> (that is defined
on <userinput>[-L,L]</userinput> and extended periodically) with coefficients
up to <varname>N</varname>th harmonic computed numerically.  The coefficients are
computed by numerical integration using
<link linkend="gel-function-NumericalIntegral"><function>NumericalIntegral</function></link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fourier_series">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FourierSeries.html">Mathworld</ulink> for more information.
          </para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalFourierSeriesFunction"/>NumericalFourierSeriesFunction</term>
         <listitem>
          <synopsis>NumericalFourierSeriesFunction (f,L,N)</synopsis>
	  <para lang="en">Return a function that is the Fourier series of
<function>f</function> with half-period <varname>L</varname> (that is defined
on <userinput>[-L,L]</userinput> and extended periodically) with coefficients
up to <varname>N</varname>th harmonic computed numerically.  This is the
trigonometric real series composed of sines and cosines.  The coefficients are
computed by numerical integration using
<link linkend="gel-function-NumericalIntegral"><function>NumericalIntegral</function></link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fourier_series">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FourierSeries.html">Mathworld</ulink> for more information.
          </para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalFourierCosineSeriesCoefficients"/>NumericalFourierCosineSeriesCoefficients</term>
         <listitem>
          <synopsis>NumericalFourierCosineSeriesCoefficients (f,L,N)</synopsis>
	  <para lang="en">Return a vector of coefficients of 
the cosine Fourier series of
<function>f</function> with half-period <varname>L</varname>.  That is,
we take <function>f</function> defined on <userinput>[0,L]</userinput>
take the even periodic extension and compute the Fourier series, which
only has cosine terms.  The series is computed up to the 
<varname>N</varname>th harmonic.  The coefficients are
computed by numerical integration using
<link linkend="gel-function-NumericalIntegral"><function>NumericalIntegral</function></link>.
Note that <userinput>a@(1)</userinput> is
the constant coefficient!  That is, <userinput>a@(n)</userinput> refers to
the term <userinput>cos(x*(n-1)*pi/L)</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fourier_series">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FourierCosineSeries.html">Mathworld</ulink> for more information.
          </para>
	  <para lang="en">Version 1.0.7 onwards.</para>
	  </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalFourierCosineSeriesFunction"/>NumericalFourierCosineSeriesFunction</term>
         <listitem>
          <synopsis>NumericalFourierCosineSeriesFunction (f,L,N)</synopsis>
	  <para lang="en">Return a function that is the cosine Fourier series of
<function>f</function> with half-period <varname>L</varname>.  That is,
we take <function>f</function> defined on <userinput>[0,L]</userinput>
take the even periodic extension and compute the Fourier series, which
only has cosine terms.  The series is computed up to the 
<varname>N</varname>th harmonic.  The coefficients are
computed by numerical integration using
<link linkend="gel-function-NumericalIntegral"><function>NumericalIntegral</function></link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fourier_series">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FourierCosineSeries.html">Mathworld</ulink> for more information.
          </para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalFourierSineSeriesCoefficients"/>NumericalFourierSineSeriesCoefficients</term>
         <listitem>
          <synopsis>NumericalFourierSineSeriesCoefficients (f,L,N)</synopsis>
	  <para lang="en">Return a vector of coefficients of 
the sine Fourier series of
<function>f</function> with half-period <varname>L</varname>.  That is,
we take <function>f</function> defined on <userinput>[0,L]</userinput>
take the odd periodic extension and compute the Fourier series, which
only has sine terms.  The series is computed up to the 
<varname>N</varname>th harmonic.  The coefficients are
computed by numerical integration using
<link linkend="gel-function-NumericalIntegral"><function>NumericalIntegral</function></link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fourier_series">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FourierSineSeries.html">Mathworld</ulink> for more information.
          </para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalFourierSineSeriesFunction"/>NumericalFourierSineSeriesFunction</term>
         <listitem>
          <synopsis>NumericalFourierSineSeriesFunction (f,L,N)</synopsis>
	  <para lang="en">Return a function that is the sine Fourier series of
<function>f</function> with half-period <varname>L</varname>.  That is,
we take <function>f</function> defined on <userinput>[0,L]</userinput>
take the odd periodic extension and compute the Fourier series, which
only has sine terms.  The series is computed up to the 
<varname>N</varname>th harmonic.  The coefficients are
computed by numerical integration using
<link linkend="gel-function-NumericalIntegral"><function>NumericalIntegral</function></link>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Fourier_series">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/FourierSineSeries.html">Mathworld</ulink> for more information.
          </para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalIntegral"/>NumericalIntegral</term>
         <listitem>
          <synopsis>NumericalIntegral (f,a,b)</synopsis>
          <para>Intégration de f entre a et b, en suivant la règle définie par <varname>NumericalIntegralFunction</varname> et en utilisant les <varname>NumericalIntegralSteps</varname> pas.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalLeftDerivative"/>NumericalLeftDerivative</term>
         <listitem>
          <synopsis>NumericalLeftDerivative (f,x0)</synopsis>
          <para>Essaie de calculer la dérivée à gauche par méthode numérique.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalLimitAtInfinity"/>NumericalLimitAtInfinity</term>
         <listitem>
          <synopsis>NumericalLimitAtInfinity (_f,step_fun,tolerance,successive_for_success,N)</synopsis>
          <para>Essaie de calculer la limite de f (step_fun(i)) lorsque i va de 1 à N.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NumericalRightDerivative"/>NumericalRightDerivative</term>
         <listitem>
          <synopsis>NumericalRightDerivative (f,x0)</synopsis>
          <para>Essaie de calculer la dérivée à droite par méthode numérique.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-OddPeriodicExtension"/>OddPeriodicExtension</term>
         <listitem>
          <synopsis>OddPeriodicExtension (f,L)</synopsis>
	  <para lang="en">Return a function that is the odd periodic extension of
<function>f</function> with half period <varname>L</varname>.  That
is a function defined on the interval <userinput>[0,L]</userinput>
extended to be odd on <userinput>[-L,L]</userinput> and then
extended to be periodic with period <userinput>2*L</userinput>.</para>
	  <para>Consultez aussi <link linkend="gel-function-EvenPeriodicExtension">EvenPeriodicExtension</link> et <link linkend="gel-function-PeriodicExtension">PeriodicExtension</link>.</para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-OneSidedFivePointFormula"/>OneSidedFivePointFormula</term>
         <listitem>
          <synopsis>OneSidedFivePointFormula (f,x0,h)</synopsis>
          <para>Calcule la dérivée d'un côté en utilisant une formule à cinq points.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-OneSidedThreePointFormula"/>OneSidedThreePointFormula</term>
         <listitem>
          <synopsis>OneSidedThreePointFormula (f,x0,h)</synopsis>
          <para>Calcule la dérivée d'un côté en utilisant une formule à trois points.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PeriodicExtension"/>PeriodicExtension</term>
         <listitem>
          <synopsis>PeriodicExtension (f,a,b)</synopsis>
	  <para lang="en">Return a function that is the periodic extension of
<function>f</function> defined on the interval <userinput>[a,b]</userinput>
and has period <userinput>b-a</userinput>.</para>
	  <para>Consultez également <link linkend="gel-function-OddPeriodicExtension">OddPeriodicExtension</link> et <link linkend="gel-function-EvenPeriodicExtension">EvenPeriodicExtension</link>.</para>
	  <para lang="en">Version 1.0.7 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RightLimit"/>RightLimit</term>
         <listitem>
          <synopsis>RightLimit (f,x0)</synopsis>
          <para>Calcule la limite à droite d'une fonction à valeurs réelles en x0.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-TwoSidedFivePointFormula"/>TwoSidedFivePointFormula</term>
         <listitem>
          <synopsis>TwoSidedFivePointFormula (f,x0,h)</synopsis>
          <para>Calcule la dérivée des deux côtés en utilisant une formule à cinq points.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-TwoSidedThreePointFormula"/>TwoSidedThreePointFormula</term>
         <listitem>
          <synopsis>TwoSidedThreePointFormula (f,x0,h)</synopsis>
          <para>Calcule la dérivée des deux côtés en utilisant une formule à trois points.</para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-functions">
      <title>Fonctions</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-Argument"/>Argument</term>
         <listitem>
          <synopsis>Argument (z)</synopsis>
          <para lang="en">Aliases: <function>Arg</function> <function>arg</function></para>
          <para>Renvoie l'argument (angle) d'un nombre complexe.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BesselJ0"/>BesselJ0</term>
         <listitem>
          <synopsis lang="en">BesselJ0 (x)</synopsis>
          <para lang="en">Bessel function of the first kind of order 0.  Only implemented for real numbers.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Bessel_functions">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BesselJ1"/>BesselJ1</term>
         <listitem>
          <synopsis lang="en">BesselJ1 (x)</synopsis>
          <para lang="en">Bessel function of the first kind of order 1.  Only implemented for real numbers.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Bessel_functions">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BesselJn"/>BesselJn</term>
         <listitem>
          <synopsis lang="en">BesselJn (n,x)</synopsis>
	  <para lang="en">Bessel function of the first kind of order <varname>n</varname>.  Only implemented for real numbers.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Bessel_functions">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BesselY0"/>BesselY0</term>
         <listitem>
          <synopsis lang="en">BesselY0 (x)</synopsis>
          <para lang="en">Bessel function of the second kind of order 0.  Only implemented for real numbers.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Bessel_functions">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BesselY1"/>BesselY1</term>
         <listitem>
          <synopsis lang="en">BesselY1 (x)</synopsis>
          <para lang="en">Bessel function of the second kind of order 1.  Only implemented for real numbers.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Bessel_functions">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-BesselYn"/>BesselYn</term>
         <listitem>
          <synopsis lang="en">BesselYn (n,x)</synopsis>
	  <para lang="en">Bessel function of the second kind of order <varname>n</varname>.  Only implemented for real numbers.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Bessel_functions">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DirichletKernel"/>DirichletKernel</term>
         <listitem>
          <synopsis>DirichletKernel (n,t)</synopsis>
	  <para lang="en">Dirichlet kernel of order <varname>n</varname>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DiscreteDelta"/>DiscreteDelta</term>
         <listitem>
          <synopsis>DiscreteDelta (v)</synopsis>
          <para>Renvoie 1 si et seulement si tous les éléments sont nuls.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-ErrorFunction"/>ErrorFunction</term>
         <listitem>
          <synopsis>ErrorFunction (x)</synopsis>
          <para>Alias : <function>erf</function></para>
          <para>Fonction erreur, 2/sqrt(pi) * int_0^x e^(-t^2) dt.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Error_function">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/ErrorFunction">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FejerKernel"/>FejerKernel</term>
         <listitem>
          <synopsis>FejerKernel (n,t)</synopsis>
          <para>Noyau Fejer d'ordre <varname>n</varname> évalué en <varname>t</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/FejerKernel">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-GammaFunction"/>GammaFunction</term>
         <listitem>
          <synopsis>GammaFunction (x)</synopsis>
          <para>Alias : <function>Gamma</function></para>
          <para>La fonction Gamma. Seules les valeurs réelles sont actuellement implémentées.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/GammaFunction">Planetmath</ulink> or
	    <ulink url="https://en.wikipedia.org/wiki/Gamma_function">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-KroneckerDelta"/>KroneckerDelta</term>
         <listitem>
          <synopsis>KroneckerDelta (v)</synopsis>
          <para>Renvoie 1 si et seulement si tous les éléments sont égaux.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LambertW"/>LambertW</term>
         <listitem>
          <synopsis lang="en">LambertW (x)</synopsis>
	  <para lang="en">
		  The principal branch of Lambert W function computed for only
		  real values greater than or equal to <userinput>-1/e</userinput>.
		  That is, <function>LambertW</function> is the inverse of
		  the expression <userinput>x*e^x</userinput>.  Even for
		  real <varname>x</varname> this expression is not one to one and
		  therefore has two branches over <userinput>[-1/e,0)</userinput>.
		  See <link linkend="gel-function-LambertWm1"><function>LambertWm1</function></link> for the other real branch.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Lambert_W_function">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LambertWm1"/>LambertWm1</term>
         <listitem>
          <synopsis lang="en">LambertWm1 (x)</synopsis>
	  <para lang="en">
		  The minus-one branch of Lambert W function computed for only
		  real values greater than or equal to <userinput>-1/e</userinput>
		  and less than 0.
		  That is, <function>LambertWm1</function> is the second
		  branch of the inverse of <userinput>x*e^x</userinput>.
		  See <link linkend="gel-function-LambertW"><function>LambertW</function></link> for the principal branch.
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Lambert_W_function">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MinimizeFunction"/>MinimizeFunction</term>
         <listitem>
          <synopsis>MinimizeFunction (fonc,x,incr)</synopsis>
          <para>Cherche la première valeur pour laquelle f(x)=0.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MoebiusDiskMapping"/>MoebiusDiskMapping</term>
         <listitem>
          <synopsis>MoebiusDiskMapping (a,z)</synopsis>
          <para>Transformation de Möbius du disque vers lui-même en faisant correspondre a à 0.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/M%C3%B6bius_transformation">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/MobiusTransformation">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MoebiusMapping"/>MoebiusMapping</term>
         <listitem>
          <synopsis>MoebiusMapping (z,z2,z3,z4)</synopsis>
          <para>Transformation de Möbius utilisant le rapport croisé en prenant z2, z3, z4 à 1, 0 et l'infini respectivement.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/M%C3%B6bius_transformation">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/MobiusTransformation">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MoebiusMappingInftyToInfty"/>MoebiusMappingInftyToInfty</term>
         <listitem>
          <synopsis>MoebiusMappingInftyToInfty (z,z2,z3)</synopsis>
          <para>Transformation de Möbius utilisant le rapport croisé en prenant l'infini à l'infini et z2, z3 à 1 et 0 respectivement.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/M%C3%B6bius_transformation">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/MobiusTransformation">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MoebiusMappingInftyToOne"/>MoebiusMappingInftyToOne</term>
         <listitem>
          <synopsis>MoebiusMappingInftyToOne (z,z3,z4)</synopsis>
          <para>Transformation de Möbius utilisant le rapport croisé en prenant l'infini à 1 et z3, z4 à 0 et l'infini respectivement.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/M%C3%B6bius_transformation">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/MobiusTransformation">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MoebiusMappingInftyToZero"/>MoebiusMappingInftyToZero</term>
         <listitem>
          <synopsis>MoebiusMappingInftyToZero (z,z2,z4)</synopsis>
          <para>Transformation de Möbius utilisant le rapport croisé en prenant l'infini à 0 et z2, z4 à 1 et l'infini respectivement.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/M%C3%B6bius_transformation">Wikipedia</ulink> or
	    <ulink url="http://planetmath.org/MobiusTransformation">Planetmath</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PoissonKernel"/>PoissonKernel</term>
         <listitem>
          <synopsis>PoissonKernel (r,sigma)</synopsis>
          <para>Le noyau de Poisson sur D(0,1) (non normalisé à 1, donc son intégrale vaut 2 pi).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PoissonKernelRadius"/>PoissonKernelRadius</term>
         <listitem>
          <synopsis>PoissonKernelRadius (r,sigma)</synopsis>
          <para>Le noyau de Poisson sur D(0,R) (non normalisé à 1).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RiemannZeta"/>RiemannZeta</term>
         <listitem>
          <synopsis>RiemannZeta (x)</synopsis>
          <para>Alias : <function>zeta</function></para>
          <para>Fonction zeta de Riemann (seules les valeurs réelles sont actuellement implémentées).</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/RiemannZetaFunction">Planetmath</ulink> or
	    <ulink url="https://en.wikipedia.org/wiki/Riemann_zeta_function">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-UnitStep"/>UnitStep</term>
         <listitem>
          <synopsis>UnitStep (x)</synopsis>
          <para>La fonction échelon vaut 0 pour x&lt;0, 1 sinon. C'est l'intégrale de la fonction delta de Dirac. Elle est aussi appelée fonction d'Heaviside.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Unit_step">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-cis"/>cis</term>
         <listitem>
          <synopsis>cis (x)</synopsis>
          <para>La fonction <function>cis</function> est la même que <userinput>cos(x)+1i*sin(x)</userinput>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-deg2rad"/>deg2rad</term>
         <listitem>
          <synopsis>deg2rad (x)</synopsis>
          <para>Convertit les degrés en radians.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-rad2deg"/>rad2deg</term>
         <listitem>
          <synopsis>rad2deg (x)</synopsis>
          <para>Convertit les radians en degrés.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-sinc"/>sinc</term>
         <listitem>
          <synopsis lang="en">sinc (x)</synopsis>
	  <para lang="en">Calculates the unnormalized sinc function, that is
		  <userinput>sin(x)/x</userinput>.
		  If you want the normalized function call <userinput>sinc(pi*x)</userinput>.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Sinc">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-equation-solving">
      <title>Résolution d'équations</title>
      <variablelist>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-CubicFormula"/>CubicFormula</term>
         <listitem>
          <synopsis>CubicFormula (p)</synopsis>
          <para>Calcule les racines d'un polynôme cubique (de degré 3) en utilisant la formule cubique. Le polynôme doit être fourni sous la forme d'un vecteur de coefficients. Par exemple <userinput>4*x^3 + 2*x + 1</userinput> correspond au vecteur <userinput>[1,2,0,4]</userinput>. Renvoie un vecteur colonne contenant les trois solutions. La première solution est toujours celle qui est réelle puisqu'un polynôme cubique possède toujours une solution réelle.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/CubicFormula">Planetmath</ulink>,
	    <ulink url="http://mathworld.wolfram.com/CubicFormula.html">Mathworld</ulink>, or
	    <ulink url="https://en.wikipedia.org/wiki/Cubic_equation">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-EulersMethod"/>EulersMethod</term>
         <listitem>
          <synopsis>EulersMethod (f,x0,y0,x1,n)</synopsis>
          <para lang="en">
	    Use classical Euler's method to numerically solve y'=f(x,y) for
	    initial <varname>x0</varname>, <varname>y0</varname> going to
	    <varname>x1</varname> with <varname>n</varname> increments,
	    returns <varname>y</varname> at <varname>x1</varname>.
	    Unless you explicitly want to use Euler's method, you should really
	    think about using
	    <link linkend="gel-function-RungeKutta">RungeKutta</link>
	    for solving ODE.
	  </para>
	  <para>Les systèmes peuvent être résolus en ayant uniquement <varname>y</varname> sous la forme d'un vecteur (colonne) partout. C'est-à-dire <varname>y0</varname> peut être un vecteur et dans ce cas <varname>f</varname> doit prendre un nombre <varname>x</varname> et un vecteur de la même taille comme deuxième argument et doit renvoyer un vecteur de la même taille.</para>
          <para lang="en">
	    See
	    <ulink url="http://mathworld.wolfram.com/EulerForwardMethod.html">Mathworld</ulink> or
	    <ulink url="https://en.wikipedia.org/wiki/Eulers_method">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-EulersMethodFull"/>EulersMethodFull</term>
         <listitem>
          <synopsis>EulersMethodFull (f,x0,y0,x1,n)</synopsis>
          <para lang="en">
	    Use classical Euler's method to numerically solve y'=f(x,y) for
	    initial <varname>x0</varname>, <varname>y0</varname> going to
	    <varname>x1</varname> with <varname>n</varname> increments,
	    returns an <userinput>n+1</userinput> by 2 matrix with the
	    <varname>x</varname> and <varname>y</varname> values.
	    Unless you explicitly want to use Euler's method, you should really
	    think about using
	    <link linkend="gel-function-RungeKuttaFull">RungeKuttaFull</link>
	    for solving ODE.
	    Suitable
	    for plugging into 
	    <link linkend="gel-function-LinePlotDrawLine">LinePlotDrawLine</link> or
	    <link linkend="gel-function-LinePlotDrawPoints">LinePlotDrawPoints</link>.
	  </para>
	  <para lang="en">
	    Example:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>LinePlotClear();</userinput>
<prompt>genius&gt;</prompt> <userinput>line = EulersMethodFull(`(x,y)=y,0,1.0,3.0,50);</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine(line,"window","fit","color","blue","legend","Exponential growth");</userinput>
</screen>
	  </para>
	  <para>Les systèmes peuvent être résolus en ayant uniquement <varname>y</varname> sous la forme d'un vecteur (colonne) partout. C'est-à-dire <varname>y0</varname> peut être un vecteur et dans ce cas <varname>f</varname> doit prendre un nombre <varname>x</varname> et un vecteur de la même taille comme deuxième argument et doit renvoyer un vecteur de la même taille.</para>
	  <para lang="en">
		  The output for a system is still a n by 2 matrix with the second
		  entry being a vector.  If you wish to plot the line, make sure to use row vectors, and then flatten the matrix with
		  <link linkend="gel-function-ExpandMatrix">ExpandMatrix</link>,
		  and pick out the right columns.  Example:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>LinePlotClear();</userinput>
<prompt>genius&gt;</prompt> <userinput>lines = EulersMethodFull(`(x,y)=[y@(2),-y@(1)],0,[1.0,1.0],10.0,500);</userinput>
<prompt>genius&gt;</prompt> <userinput>lines = ExpandMatrix(lines);</userinput>
<prompt>genius&gt;</prompt> <userinput>firstline = lines@(,[1,2]);</userinput>
<prompt>genius&gt;</prompt> <userinput>secondline = lines@(,[1,3]);</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotWindow = [0,10,-2,2];</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine(firstline,"color","blue","legend","First");</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawPoints(secondline,"color","red","thickness",3,"legend","Second");</userinput>
</screen>
	  </para>
          <para lang="en">
	    See
	    <ulink url="http://mathworld.wolfram.com/EulerForwardMethod.html">Mathworld</ulink> or
	    <ulink url="https://en.wikipedia.org/wiki/Eulers_method">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.10 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FindRootBisection"/>FindRootBisection</term>
         <listitem>
          <synopsis>FindRootBisection (f,a,b,TOL,N)</synopsis>
          <para lang="en">Find root of a function using the bisection method.
		  <varname>a</varname> and <varname>b</varname> are the initial guess interval,
		  <userinput>f(a)</userinput> and <userinput>f(b)</userinput> should have opposite signs.
	    <varname>TOL</varname> is the desired tolerance and
<varname>N</varname> is the limit on the number of iterations to run, 0 means no limit.  The function returns a vector <userinput>[success,value,iteration]</userinput>, where <varname>success</varname> is a boolean indicating success, <varname>value</varname> is the last value computed, and <varname>iteration</varname> is the number of iterations done.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FindRootFalsePosition"/>FindRootFalsePosition</term>
         <listitem>
          <synopsis>FindRootFalsePosition (f,a,b,TOL,N)</synopsis>
          <para lang="en">Find root of a function using the method of false position.
		  <varname>a</varname> and <varname>b</varname> are the initial guess interval,
		  <userinput>f(a)</userinput> and <userinput>f(b)</userinput> should have opposite signs.
	    <varname>TOL</varname> is the desired tolerance and
<varname>N</varname> is the limit on the number of iterations to run, 0 means no limit.  The function returns a vector <userinput>[success,value,iteration]</userinput>, where <varname>success</varname> is a boolean indicating success, <varname>value</varname> is the last value computed, and <varname>iteration</varname> is the number of iterations done.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FindRootMullersMethod"/>FindRootMullersMethod</term>
         <listitem>
          <synopsis lang="en">FindRootMullersMethod (f,x0,x1,x2,TOL,N)</synopsis>
          <para>Cherche la racine d'une fonction en utilisant la méthode de Muller. <varname>TOL</varname> est la tolérance permise et <varname>N</varname> est la limite du nombre d'itérations réalisées, 0 signifiant pas de limite. La fonction renvoie un vecteur <userinput>[succes,valeur,itération]</userinput> dans lequel <varname>succes</varname> est un booléen indiquant la réussite, <varname>valeur</varname> est la dernière valeur calculée et <varname>itération</varname> est le nombre d'itérations réalisées.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-FindRootSecant"/>FindRootSecant</term>
         <listitem>
          <synopsis>FindRootSecant (f,a,b,TOL,N)</synopsis>
          <para lang="en">Find root of a function using the secant method.
		  <varname>a</varname> and <varname>b</varname> are the initial guess interval,
		  <userinput>f(a)</userinput> and <userinput>f(b)</userinput> should have opposite signs.
	    <varname>TOL</varname> is the desired tolerance and
<varname>N</varname> is the limit on the number of iterations to run, 0 means no limit.  The function returns a vector <userinput>[success,value,iteration]</userinput>, where <varname>success</varname> is a boolean indicating success, <varname>value</varname> is the last value computed, and <varname>iteration</varname> is the number of iterations done.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-HalleysMethod"/>HalleysMethod</term>
         <listitem>
          <synopsis lang="en">HalleysMethod (f,df,ddf,guess,epsilon,maxn)</synopsis>
	  <para lang="en">Find zeros using Halley's method.  <varname>f</varname> is
		  the function, <varname>df</varname> is the derivative of
		  <varname>f</varname>, and <varname>ddf</varname> is the second derivative of
		  <varname>f</varname>.  <varname>guess</varname> is the initial
		  guess.  The function returns after two successive values are
		  within <varname>epsilon</varname> of each other, or after <varname>maxn</varname> tries, in which case the function returns <constant>null</constant> indicating failure.
	  </para>
	  <para lang="en">
	  See also <link linkend="gel-function-NewtonsMethod"><function>NewtonsMethod</function></link> and <link linkend="gel-function-SymbolicDerivative"><function>SymbolicDerivative</function></link>.
  	  </para>
	  <para lang="en">
	    Example to find the square root of 10:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>HalleysMethod(`(x)=x^2-10,`(x)=2*x,`(x)=2,3,10^-10,100)</userinput>
</screen>
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Halley%27s_method">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NewtonsMethod"/>NewtonsMethod</term>
         <listitem>
          <synopsis lang="en">NewtonsMethod (f,df,guess,epsilon,maxn)</synopsis>
	  <para lang="en">Find zeros using Newton's method.  <varname>f</varname> is
		  the function and <varname>df</varname> is the derivative of
		  <varname>f</varname>.  <varname>guess</varname> is the initial
		  guess.  The function returns after two successive values are
		  within <varname>epsilon</varname> of each other, or after <varname>maxn</varname> tries, in which case the function returns <constant>null</constant> indicating failure.
	  </para>
	  <para lang="en">
	  See also <link linkend="gel-function-NewtonsMethodPoly"><function>NewtonsMethodPoly</function></link> and <link linkend="gel-function-SymbolicDerivative"><function>SymbolicDerivative</function></link>.
  	  </para>
	  <para lang="en">
	    Example to find the square root of 10:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>NewtonsMethod(`(x)=x^2-10,`(x)=2*x,3,10^-10,100)</userinput>
</screen>
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Newtons_method">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PolynomialRoots"/>PolynomialRoots</term>
         <listitem>
          <synopsis>PolynomialRoots (p)</synopsis>
          <para>Calcule les racines d'un polynôme (de degré 1 à 4) en utilisant une des formules adaptée à ce type de polynôme. Le polynôme doit être fourni sous la forme d'un vecteur de coefficients. Par exemple <userinput>4*x^3 + 2*x + 1</userinput> correspond au vecteur <userinput>[1,2,0,4]</userinput>. Renvoie un vecteur colonne contenant les solutions.</para>
	  <para>La fonction appelle <link linkend="gel-function-QuadraticFormula">QuadraticFormula</link>, <link linkend="gel-function-CubicFormula">CubicFormula</link> et <link linkend="gel-function-QuarticFormula">QuarticFormula</link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-QuadraticFormula"/>QuadraticFormula</term>
         <listitem>
          <synopsis>QuadraticFormula (p)</synopsis>
          <para>Calcule les racines d'un polynôme quadratique (de degré 2) en utilisant la formule quadratique. Le polynôme doit être fourni sous la forme d'un vecteur de coefficients. <userinput>3*x^2 + 2*x + 1</userinput> correspond au vecteur <userinput>[1,2,3]</userinput>. Renvoie un vecteur colonne contenant les deux solutions.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/QuadraticFormula">Planetmath</ulink>, or
	    <ulink url="http://mathworld.wolfram.com/QuadraticFormula.html">Mathworld</ulink>, or
	    <ulink url="https://en.wikipedia.org/wiki/Quadratic_formula">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-QuarticFormula"/>QuarticFormula</term>
         <listitem>
          <synopsis>QuarticFormula (p)</synopsis>
          <para>Calcule les racines d'un polynôme quartique (de degré 4) en utilisant la formule quartique. Le polynôme doit être fourni sous la forme d'un vecteur de coefficients. <userinput>5*x^4 + 2*x + 1</userinput> correspond au vecteur <userinput>[1,2,0,0,5]</userinput>. Renvoie un vecteur colonne contenant les quatre solutions.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/QuarticFormula">Planetmath</ulink>,
	    <ulink url="http://mathworld.wolfram.com/QuarticEquation.html">Mathworld</ulink>, or
	    <ulink url="https://en.wikipedia.org/wiki/Quartic_equation">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RungeKutta"/>RungeKutta</term>
         <listitem>
          <synopsis>RungeKutta (f,x0,y0,x1,n)</synopsis>
          <para>Utilise la méthode classique non adaptative de Runge-Kutta du quatrième ordre pour résoudre numériquement y'=f(x,y) avec les valeurs initiales <varname>x0</varname>, <varname>y0</varname> allant vers <varname>x1</varname> avec <varname>n</varname> incréments, renvoie <varname>y</varname> en <varname>x1</varname>.</para>
	  <para>Les systèmes peuvent être résolus en ayant uniquement <varname>y</varname> sous la forme d'un vecteur (colonne) partout. C'est-à-dire <varname>y0</varname> peut être un vecteur et dans ce cas <varname>f</varname> doit prendre un nombre <varname>x</varname> et un vecteur de la même taille comme deuxième argument et doit renvoyer un vecteur de la même taille.</para>
          <para lang="en">
	    See
	    <ulink url="http://mathworld.wolfram.com/Runge-KuttaMethod.html">Mathworld</ulink> or
	    <ulink url="https://en.wikipedia.org/wiki/Runge-Kutta_methods">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RungeKuttaFull"/>RungeKuttaFull</term>
         <listitem>
          <synopsis>RungeKuttaFull (f,x0,y0,x1,n)</synopsis>
          <para lang="en">
	    Use classical non-adaptive fourth order Runge-Kutta method to
	    numerically solve
	    y'=f(x,y) for initial <varname>x0</varname>, <varname>y0</varname>
	    going to <varname>x1</varname> with <varname>n</varname>
	    increments,
	    returns an <userinput>n+1</userinput> by 2 matrix with the
	    <varname>x</varname> and <varname>y</varname> values.  Suitable
	    for plugging into 
	    <link linkend="gel-function-LinePlotDrawLine">LinePlotDrawLine</link> or
	    <link linkend="gel-function-LinePlotDrawPoints">LinePlotDrawPoints</link>.
	  </para>
	  <para lang="en">
	    Example:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>LinePlotClear();</userinput>
<prompt>genius&gt;</prompt> <userinput>line = RungeKuttaFull(`(x,y)=y,0,1.0,3.0,50);</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine(line,"window","fit","color","blue","legend","Exponential growth");</userinput>
</screen>
	  </para>
	  <para>Les systèmes peuvent être résolus en ayant uniquement <varname>y</varname> sous la forme d'un vecteur (colonne) partout. C'est-à-dire <varname>y0</varname> peut être un vecteur et dans ce cas <varname>f</varname> doit prendre un nombre <varname>x</varname> et un vecteur de la même taille comme deuxième argument et doit renvoyer un vecteur de la même taille.</para>
	  <para lang="en">
		  The output for a system is still a n by 2 matrix with the second
		  entry being a vector.  If you wish to plot the line, make sure to use row vectors, and then flatten the matrix with
		  <link linkend="gel-function-ExpandMatrix">ExpandMatrix</link>,
		  and pick out the right columns.  Example:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>LinePlotClear();</userinput>
<prompt>genius&gt;</prompt> <userinput>lines = RungeKuttaFull(`(x,y)=[y@(2),-y@(1)],0,[1.0,1.0],10.0,100);</userinput>
<prompt>genius&gt;</prompt> <userinput>lines = ExpandMatrix(lines);</userinput>
<prompt>genius&gt;</prompt> <userinput>firstline = lines@(,[1,2]);</userinput>
<prompt>genius&gt;</prompt> <userinput>secondline = lines@(,[1,3]);</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotWindow = [0,10,-2,2];</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine(firstline,"color","blue","legend","First");</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawPoints(secondline,"color","red","thickness",3,"legend","Second");</userinput>
</screen>
	  </para>
          <para lang="en">
	    See
	    <ulink url="http://mathworld.wolfram.com/Runge-KuttaMethod.html">Mathworld</ulink> or
	    <ulink url="https://en.wikipedia.org/wiki/Runge-Kutta_methods">Wikipedia</ulink> for more information.
	  </para>
	  <para lang="en">Version 1.0.10 onwards.</para>
         </listitem>
        </varlistentry>


      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-statistics">
      <title>Statistiques</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-Average"/>Average</term>
         <listitem>
          <synopsis>Average (m)</synopsis>
          <para lang="en">Aliases: <function>average</function> <function>Mean</function> <function>mean</function></para>
          <para lang="en">Calculate average (the arithmetic mean) of an entire matrix.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Mean">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/ArithmeticMean.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-GaussDistribution"/>GaussDistribution</term>
         <listitem>
          <synopsis>GaussDistribution (x,sigma)</synopsis>
	  <para>Intégrale de la fonction de Gauss de 0 à <varname>x</varname> (aire sous la courbe normale).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Normal_distribution">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/NormalDistribution.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-GaussFunction"/>GaussFunction</term>
         <listitem>
          <synopsis>GaussFunction (x,sigma)</synopsis>
          <para>Fonction distribution de Gauss normalisée (courbe normale).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Normal_distribution">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/NormalDistribution.html">Mathworld</ulink> for more information.
	  </para>

         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Median"/>Median</term>
         <listitem>
          <synopsis>Median (m)</synopsis>
          <para>Alias : <function>median</function></para>
          <para>Calcule la médiane de toute une matrice.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Median">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/StatisticalMedian.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PopulationStandardDeviation"/>PopulationStandardDeviation</term>
         <listitem>
          <synopsis>PopulationStandardDeviation (m)</synopsis>
          <para>Alias : <function>stdevp</function></para>
          <para>Calcule l'écart type de la population de toute une matrice.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RowAverage"/>RowAverage</term>
         <listitem>
          <synopsis>RowAverage (m)</synopsis>
          <para>Alias : <function>RowMean</function></para>
	  <para lang="en">Calculate average of each row in a matrix.  That is, compute the
	  arithmetic mean.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Mean">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/ArithmeticMean.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RowMedian"/>RowMedian</term>
         <listitem>
          <synopsis>RowMedian (m)</synopsis>
          <para>Calcule la médiane de chaque ligne d'une matrice et renvoie un vecteur colonne.</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Median">Wikipedia</ulink> or
	    <ulink url="http://mathworld.wolfram.com/StatisticalMedian.html">Mathworld</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RowPopulationStandardDeviation"/>RowPopulationStandardDeviation</term>
         <listitem>
          <synopsis>RowPopulationStandardDeviation (m)</synopsis>
          <para>Alias : <function>rowstdevp</function></para>
          <para>Calcule l'écart type de la population des lignes d'une matrice et renvoie un vecteur colonne.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-RowStandardDeviation"/>RowStandardDeviation</term>
         <listitem>
          <synopsis>RowStandardDeviation (m)</synopsis>
          <para>Alias : <function>rowstdev</function></para>
          <para>Calcule l'écart type des lignes d'une matrice et renvoie un vecteur colonne.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
	 <term lang="en"><anchor id="gel-function-StandardDeviation"/>StandardDeviation</term>
         <listitem>
          <synopsis>StandardDeviation (m)</synopsis>
          <para>Alias : <function>stdev</function></para>
          <para>Calcule l'écart type de toute une matrice.</para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-polynomials">
      <title>Polynômes</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-AddPoly"/>AddPoly</term>
         <listitem>
          <synopsis>AddPoly (p1,p2)</synopsis>
          <para>Ajoute deux polynômes (vecteurs).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-DividePoly"/>DividePoly</term>
         <listitem>
          <synopsis>DividePoly (p,q,&amp;r)</synopsis>
          <para>Divise deux polynômes (en tant que vecteurs) en utilisant la division longue. Renvoie le quotient des deux polynômes. L'argument optionnel <varname>r</varname> est utilisé pour renvoyer le reste. Le reste a un degré plus bas que <varname>q</varname>.</para>
          <para lang="en">
	    See
	    <ulink url="http://planetmath.org/PolynomialLongDivision">Planetmath</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsPoly"/>IsPoly</term>
         <listitem>
          <synopsis>IsPoly (p)</synopsis>
          <para>Vérifie qu'un vecteur est utilisable en tant que polynôme.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MultiplyPoly"/>MultiplyPoly</term>
         <listitem>
          <synopsis>MultiplyPoly (p1,p2)</synopsis>
          <para>Multiplie deux polynômes (comme vecteurs).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-NewtonsMethodPoly"/>NewtonsMethodPoly</term>
         <listitem>
          <synopsis>NewtonsMethodPoly (poly,valeurinitiale,epsilon,maxn)</synopsis>
	  <para lang="en">Find a root of a polynomial using Newton's method.  <varname>poly</varname> is
		  the polynomial as a vector and <varname>guess</varname> is the initial
		  guess.  The function returns after two successive values are
		  within <varname>epsilon</varname> of each other, or after <varname>maxn</varname> tries, in which case the function returns <constant>null</constant> indicating failure.
	  </para>
	  <para lang="en">
	  See also <link linkend="gel-function-NewtonsMethod"><function>NewtonsMethod</function></link>.
  	  </para>
	  <para lang="en">
	    Example to find the square root of 10:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>NewtonsMethodPoly([-10,0,1],3,10^-10,100)</userinput>
</screen>
	  </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Newtons_method">Wikipedia</ulink> for more information.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Poly2ndDerivative"/>Poly2ndDerivative</term>
         <listitem>
          <synopsis>Poly2ndDerivative (p)</synopsis>
          <para>Renvoie la dérivée seconde du polynôme (comme vecteur).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PolyDerivative"/>PolyDerivative</term>
         <listitem>
          <synopsis>PolyDerivative (p)</synopsis>
          <para>Prend la dérivée du polynôme (comme vecteur).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PolyToFunction"/>PolyToFunction</term>
         <listitem>
          <synopsis>PolyToFunction (p)</synopsis>
          <para>Fabrique une fonction à partir d'un polynôme (comme vecteur).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PolyToString"/>PolyToString</term>
         <listitem>
          <synopsis>PolyToString (p,var...)</synopsis>
          <para>Fabrique une chaîne à partir d'un polynôme (comme vecteur).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SubtractPoly"/>SubtractPoly</term>
         <listitem>
          <synopsis>SubtractPoly (p1,p2)</synopsis>
          <para>Soustrait deux polynômes (comme vecteur).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-TrimPoly"/>TrimPoly</term>
         <listitem>
          <synopsis>TrimPoly (p)</synopsis>
          <para>Tronque les zéros d'un polynôme (défini comme vecteur).</para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-set-theory">
      <title>Théorie des ensembles</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-Intersection"/>Intersection</term>
         <listitem>
          <synopsis>Intersection (X,Y)</synopsis>
          <para>Renvoie l'intersection, selon la théorie des ensembles, de X et Y (X et Y sont des vecteurs supposés être des ensembles).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsIn"/>IsIn</term>
         <listitem>
          <synopsis>IsIn (x,X)</synopsis>
	  <para>Renvoie <constant>true</constant> (vrai) si l'élément x fait partie de l'ensemble X (où X est un vecteur supposé être un ensemble).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-IsSubset"/>IsSubset</term>
         <listitem>
          <synopsis>IsSubset (X, Y)</synopsis>
	  <para>Renvoie <constant>true</constant> (vrai) si X est un sous-ensemble de Y (X et Y sont des vecteurs supposés être des ensembles).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MakeSet"/>MakeSet</term>
         <listitem>
          <synopsis>MakeSet (X)</synopsis>
          <para>Renvoie un vecteur où chaque élément de X n'apparaît qu'une seule fois.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SetMinus"/>SetMinus</term>
         <listitem>
          <synopsis>SetMinus (X,Y)</synopsis>
          <para>Renvoie la différence X-Y selon la théorie des ensembles (X et Y sont des vecteurs supposés être des ensembles).</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-Union"/>Union</term>
         <listitem>
          <synopsis>Union (X,Y)</synopsis>
          <para>Renvoie l'union, selon la théorie des ensembles, de X et Y (X et Y sont des vecteurs supposés être des ensembles).</para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-commutative-algebra">
      <title lang="en">Commutative Algebra</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-MacaulayBound"/>MacaulayBound</term>
         <listitem>
          <synopsis lang="en">MacaulayBound (c,d)</synopsis>
          <para lang="en">For a Hilbert function that is c for degree d, given the Macaulay bound for the Hilbert function of degree d+1 (The c^&lt;d&gt; operator from Green's proof).</para>
	  <para lang="en">Version 1.0.15 onwards.</para>
         </listitem>
        </varlistentry>
	
        <varlistentry>
         <term lang="en"><anchor id="gel-function-MacaulayLowerOperator"/>MacaulayLowerOperator</term>
         <listitem>
          <synopsis lang="en">MacaulayLowerOperator (c,d)</synopsis>
          <para lang="en">The c_&lt;d&gt; operator from Green's proof of Macaulay's Theorem.</para>
	  <para lang="en">Version 1.0.15 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-MacaulayRep"/>MacaulayRep</term>
         <listitem>
          <synopsis lang="en">MacaulayRep (c,d)</synopsis>
          <para lang="en">Return the dth Macaulay representation of a positive integer c.</para>
	  <para lang="en">Version 1.0.15 onwards.</para>
         </listitem>
        </varlistentry>
      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-miscellaneous">
      <title>Divers</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-ASCIIToString"/>ASCIIToString</term>
         <listitem>
          <synopsis>ASCIIToString (vec)</synopsis>
          <para lang="en">Convert a vector of ASCII values to a string.
		  See also
		  <link linkend="gel-function-StringToASCII"><function>StringToASCII</function></link>.
          </para>
          <para lang="en">
	    Example:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>ASCIIToString([97,98,99])</userinput>
= "abc"
</screen>
          </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/ASCII">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-AlphabetToString"/>AlphabetToString</term>
         <listitem>
          <synopsis>AlphabetToString (vec,alphabet)</synopsis>
	  <para lang="en">Convert a vector of 0-based alphabet values (positions in the alphabet string) to a string.  A <constant>null</constant> vector results in an empty string.
		  See also
		  <link linkend="gel-function-StringToAlphabet"><function>StringToAlphabet</function></link>.
          </para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>AlphabetToString([1,2,3,0,0],"abcd")</userinput>
= "bcdaa"
<prompt>genius&gt;</prompt> <userinput>AlphabetToString(null,"abcd")</userinput>
= ""
</screen>
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-StringToASCII"/>StringToASCII</term>
         <listitem>
          <synopsis>StringToASCII (chaîne)</synopsis>
	  <para lang="en">Convert a string to a (row) vector of ASCII values.
		  See also
		  <link linkend="gel-function-ASCIIToString"><function>ASCIIToString</function></link>.
          </para>
          <para lang="en">
	    Example:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>StringToASCII("abc")</userinput>
= [97, 98, 99]
</screen>
          </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/ASCII">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-StringToAlphabet"/>StringToAlphabet</term>
         <listitem>
          <synopsis>StringToAlphabet (chaîne,alphabet)</synopsis>
	  <para lang="en">Convert a string to a (row) vector of 0-based alphabet values
		  (positions in the alphabet string), -1's for unknown letters.
		  An empty string results in a <constant>null</constant>.
		  See also
		  <link linkend="gel-function-AlphabetToString"><function>AlphabetToString</function></link>.
          </para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>StringToAlphabet("cca","abcd")</userinput>
= [2, 2, 0]
<prompt>genius&gt;</prompt> <userinput>StringToAlphabet("ccag","abcd")</userinput>
= [2, 2, 0, -1]
</screen>
          </para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-symbolic">
      <title>Calcul symbolique</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-SymbolicDerivative"/>SymbolicDerivative</term>
         <listitem>
          <synopsis>SymbolicDerivative (f)</synopsis>
          <para>Essaie de dériver symboliquement la fonction f, où f est une fonction à une variable.</para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>SymbolicDerivative(sin)</userinput>
= (`(x)=cos(x))
<prompt>genius&gt;</prompt> <userinput>SymbolicDerivative(`(x)=7*x^2)</userinput>
= (`(x)=(7*(2*x)))
</screen>
          </para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Derivative">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SymbolicDerivativeTry"/>SymbolicDerivativeTry</term>
         <listitem>
          <synopsis>SymbolicDerivativeTry (f)</synopsis>
	  <para>Essaie de dériver symboliquement la fonction f, où f est une fonction à une variable, renvoie <constant>null</constant> en cas d'échec mais reste silencieux (consultez <link linkend="gel-function-SymbolicDerivative"><function>SymbolicDerivative</function></link>).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Derivative">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SymbolicNthDerivative"/>SymbolicNthDerivative</term>
         <listitem>
          <synopsis>SymbolicNthDerivative (f,n)</synopsis>
          <para>Essaie de dériver symboliquement une fonction n fois (consultez <link linkend="gel-function-SymbolicDerivative"><function>SymbolicDerivative</function></link>).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Derivative">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SymbolicNthDerivativeTry"/>SymbolicNthDerivativeTry</term>
         <listitem>
          <synopsis>SymbolicNthDerivativeTry (f,n)</synopsis>
	  <para>Essaie de dériver symboliquement une fonction n fois silencieusement et renvoie <constant>null</constant> en cas d'échec (consultez <link linkend="gel-function-SymbolicNthDerivative"><function>SymbolicNthDerivative</function></link>).</para>
          <para lang="en">
	    See
	    <ulink url="https://en.wikipedia.org/wiki/Derivative">Wikipedia</ulink> for more information.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SymbolicTaylorApproximationFunction"/>SymbolicTaylorApproximationFunction</term>
         <listitem>
          <synopsis>SymbolicTaylorApproximationFunction (f,x0,n)</synopsis>
	  <para lang="en">Attempt to construct the Taylor approximation function around x0 to the nth degree.
	  (See <link linkend="gel-function-SymbolicDerivative"><function>SymbolicDerivative</function></link>)
          </para>
         </listitem>
        </varlistentry>
      </variablelist>
    </sect1>

    <sect1 id="genius-gel-function-list-plotting">
      <title>Tracé de graphiques</title>
      <variablelist>
        <varlistentry>
         <term lang="en"><anchor id="gel-function-ExportPlot"/>ExportPlot</term>
         <listitem>
          <synopsis lang="en">ExportPlot (file,type)</synopsis>
          <synopsis lang="en">ExportPlot (file)</synopsis>
          <para lang="en">
		  Export the contents of the plotting window to a file.
		  The type is a string that specifies the file type to
		  use, "png", "eps", or "ps".  If the type is not
		  specified, then it is taken to be the extension, in
		  which case the extension must be ".png", ".eps", or ".ps".
	  </para>
	  <para lang="en">
		  Note that files are overwritten without asking.
	  </para>
	  <para lang="en">
		  On successful export, true is returned.  Otherwise
		  error is printed and exception is raised.
	  </para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>ExportPlot("file.png")</userinput>
<prompt>genius&gt;</prompt> <userinput>ExportPlot("/directory/file","eps")</userinput>
</screen>
          </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlot"/>LinePlot</term>
         <listitem>
          <synopsis>LinePlot (fonc1,fonc2,fonc3,...)</synopsis>
          <synopsis lang="en">LinePlot (func1,func2,func3,x1,x2)</synopsis>
          <synopsis>LinePlot (fonc1,fonc2,fonc3,x1,x2,y1,y2)</synopsis>
          <synopsis lang="en">LinePlot (func1,func2,func3,[x1,x2])</synopsis>
          <synopsis lang="en">LinePlot (func1,func2,func3,[x1,x2,y1,y2])</synopsis>
          <para lang="en">
	    Plot a function (or several functions) with a line.
	    First (up to 10) arguments are functions, then optionally
            you can specify the limits of the plotting window as
	    <varname>x1</varname>, <varname>x2</varname>,
	    <varname>y1</varname>, <varname>y2</varname>.  If limits are not
	    specified, then the currently set limits apply
	    (See <link linkend="gel-function-LinePlotWindow"><function>LinePlotWindow</function></link>)
	    If the y limits are not specified, then the functions are computed and then the maxima and minima
	    are used.
          </para>
          <para>Le paramètre <link linkend="gel-function-LinePlotDrawLegends"><function>LinePlotDrawLegends</function></link> conditionne l'affichage de la légende.</para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>LinePlot(sin,cos)</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlot(`(x)=x^2,-1,1,0,1)</userinput>
</screen>
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotClear"/>LinePlotClear</term>
         <listitem>
          <synopsis>LinePlotClear ()</synopsis>
          <para>Affiche la fenêtre d'affichage du tracé et efface les courbes déjà tracées.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotCParametric"/>LinePlotCParametric</term>
         <listitem>
          <synopsis>LinePlotCParametric (fonc,...)</synopsis>
          <synopsis>LinePlotCParametric (fonc,t1,t2,tinc)</synopsis>
          <synopsis>LinePlotCParametric (fonc,t1,t2,tinc,x1,x2,y1,y2)</synopsis>
          <para>Trace la courbe d'une fonction paramétrique à valeurs complexes. En premier vient la fonction qui renvoie <computeroutput>x+iy</computeroutput> puis, en option, les limites de <varname>t</varname> sous la forme <userinput>t1,t2,tinc</userinput> puis, en option, les limites de la fenêtre de tracé sous la forme <userinput>x1,x2,y1,y2</userinput>.</para>
	  <para lang="en">
	    If limits are not
	    specified, then the currently set limits apply
	    (See <link linkend="gel-function-LinePlotWindow"><function>LinePlotWindow</function></link>).
	    If instead the string "fit" is given for the x and y limits, then the limits are the maximum extent of
	    the graph
          </para>
          <para>Le paramètre <link linkend="gel-function-LinePlotDrawLegends"><function>LinePlotDrawLegends</function></link> conditionne l'affichage de la légende.</para>
         </listitem>
        </varlistentry>


        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotDrawLine"/>LinePlotDrawLine</term>
         <listitem>
          <synopsis>LinePlotDrawLine (x1,y1,x2,y2,...)</synopsis>
          <synopsis>LinePlotDrawLine (v,...)</synopsis>
          <para lang="en">
	    Draw a line from <varname>x1</varname>,<varname>y1</varname> to
	    <varname>x2</varname>,<varname>y2</varname>.
	    <varname>x1</varname>,<varname>y1</varname>,
	    <varname>x2</varname>,<varname>y2</varname> can be replaced by an
	    <varname>n</varname> by 2 matrix for a longer polyline.
	    Alternatively the vector <varname>v</varname> may be a column vector of complex numbers,
	    that is an <varname>n</varname> by 1 matrix and each complex number is then
	    considered a point in the plane.
          </para>
          <para lang="en">
	    Extra parameters can be added to specify line color, thickness,
	    arrows, the plotting window, or legend.
	    You can do this by adding an argument string <userinput>"color"</userinput>, 
	    <userinput>"thickness"</userinput>,
	    <userinput>"window"</userinput>, 
	    <userinput>"arrow"</userinput>, or <userinput>"legend"</userinput>, and after it specify
	    the color, the thickness, the window
	    as 4-vector, type of arrow, or the legend.  (Arrow and window are from version 1.0.6 onwards.)
    	  </para>
	  <para lang="en">
	    If the line is to be treated as a filled polygon, filled with the given color, you
	    can specify the argument <userinput>"filled"</userinput>.  Since version 1.0.22 onwards.
	  </para>
    	  <para lang="en">
	    The color should be either a string indicating the common English word for the color
	    that GTK will recognize such as 
            <userinput>"red"</userinput>, <userinput>"blue"</userinput>, <userinput>"yellow"</userinput>, etc...
	    Alternatively the color can be specified in RGB format as
	    <userinput>"#rgb"</userinput>, <userinput>"#rrggbb"</userinput>, or
	    <userinput>"#rrrrggggbbbb"</userinput>, where the r, g, or b are hex digits of the red, green, and blue
	    components of the color.  Finally, since version 1.0.18, the color
	    can also be specified as a real vector specifying the red green and
	    blue components where the components are between 0 and 1, e.g. <userinput>[1.0,0.5,0.1]</userinput>.
    	  </para>
    	  <para lang="en">
	    The window should be given as usual as <userinput>[x1,x2,y1,y2]</userinput>, or
	    alternatively can be given as a string
	    <userinput>"fit"</userinput> in which case,
	    the x range will be set precisely and the y range will be set with
	    five percent borders around the line.
    	  </para>
    	  <para lang="en">
	    Arrow specification should be
	    <userinput>"origin"</userinput>,
	    <userinput>"end"</userinput>,
	    <userinput>"both"</userinput>, or
	    <userinput>"none"</userinput>.
    	  </para>
    	  <para lang="en">
	    Finally, legend should be a string that can be used as the legend in the
	    graph.  That is, if legends are being printed.
          </para>
	  <para lang="en">
	  Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine(0,0,1,1,"color","blue","thickness",3)</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine([0,0;1,-1;-1,-1])</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine([0,0;1,1],"arrow","end")</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine(RungeKuttaFull(`(x,y)=y,0,0.001,10,100),"color","blue","legend","The Solution")</userinput>
<prompt>genius&gt;</prompt> <userinput>for r=0.0 to 1.0 by 0.1 do LinePlotDrawLine([0,0;1,r],"color",[r,(1-r),0.5],"window",[0,1,0,1])</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawLine([0,0;10,0;10,10;0,10],"filled","color","green")</userinput>
</screen>
          </para>
	  <para lang="en">
		  Unlike many other functions that do not care if they take a
		  column or a row vector, if specifying points as a vector of
		  complex values, due to possible ambiguities, it must always
		  be given as a column vector.
	  </para>
	  <para lang="en">
		  Specifying <varname>v</varname> as a column vector of complex numbers is
		  implemented from version 1.0.22 and onwards.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotDrawPoints"/>LinePlotDrawPoints</term>
         <listitem>
          <synopsis lang="en">LinePlotDrawPoints (x,y,...)</synopsis>
          <synopsis lang="en">LinePlotDrawPoints (v,...)</synopsis>
          <para lang="en">
		  Draw a point at <varname>x</varname>,<varname>y</varname>.
		  The input can be an <varname>n</varname> by 2 matrix
		  for <varname>n</varname> different points.  This function has essentially the same
		  input as <link linkend="gel-function-LinePlotDrawLine">LinePlotDrawLine</link>.
		  Alternatively the vector <varname>v</varname> may be a column vector of complex numbers,
		  that is an <varname>n</varname> by 1 matrix and each complex number is then
		  considered a point in the plane.
          </para>
          <para lang="en">
	    Extra parameters can be added to specify color, thickness,
	    the plotting window, or legend.
	    You can do this by adding an argument string <userinput>"color"</userinput>, 
	    <userinput>"thickness"</userinput>,
	    <userinput>"window"</userinput>, 
	    or <userinput>"legend"</userinput>, and after it specify
	    the color, the thickness, the window
	    as 4-vector, or the legend.
    	  </para>
    	  <para lang="en">
	    The color should be either a string indicating the common English word for the color
	    that GTK will recognize such as 
            <userinput>"red"</userinput>, <userinput>"blue"</userinput>, <userinput>"yellow"</userinput>, etc...
	    Alternatively the color can be specified in RGB format as
	    <userinput>"#rgb"</userinput>, <userinput>"#rrggbb"</userinput>, or
	    <userinput>"#rrrrggggbbbb"</userinput>, where the r, g, or b are hex digits of the red, green, and blue
	    components of the color.  Finally the color can also be specified as a real vector specifying the red green
	    and blue components where the components are between 0 and 1.
    	  </para>
    	  <para lang="en">
	    The window should be given as usual as <userinput>[x1,x2,y1,y2]</userinput>, or
	    alternatively can be given as a string
	    <userinput>"fit"</userinput> in which case,
	    the x range will be set precisely and the y range will be set with
	    five percent borders around the line.
    	  </para>
    	  <para lang="en">
	    Finally, legend should be a string that can be used as the legend in the
	    graph.  That is, if legends are being printed.
          </para>
	  <para lang="en">
	  Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>LinePlotDrawPoints(0,0,"color","blue","thickness",3)</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawPoints([0,0;1,-1;-1,-1])</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawPoints(RungeKuttaFull(`(x,y)=y,0,0.001,10,100),"color","blue","legend","The Solution")</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawPoints([1;1+1i;1i;0],"thickness",5)</userinput>
<prompt>genius&gt;</prompt> <userinput>LinePlotDrawPoints(ApplyOverMatrix((0:6)',`(k)=exp(k*2*pi*1i/7)),"thickness",3,"legend","The 7th roots of unity")</userinput>
</screen>
          </para>
	  <para lang="en">
		  Unlike many other functions that do not care if they take a
		  column or a row vector, if specifying points as a vector of
		  complex values, due to possible ambiguities, it must always
		  be given as a column vector.  Therefore, notice in the
		  last example the transpose of the vector <userinput>0:6</userinput>
		  to make it into a column vector.
	  </para>
	  <para lang="en">
		  Available from version 1.0.18 onwards.  Specifying
		  <varname>v</varname> as a column vector of complex numbers is
		  implemented from version 1.0.22 and onwards.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotMouseLocation"/>LinePlotMouseLocation</term>
         <listitem>
          <synopsis lang="en">LinePlotMouseLocation ()</synopsis>
          <para lang="en">
	    Returns a row vector of a point on the line plot corresponding to
	    the current mouse location.  If the line plot is not visible,
	    then prints an error and returns <constant>null</constant>.
	    In this case you should run
	    <link linkend="gel-function-LinePlot"><function>LinePlot</function></link> or
	    <link linkend="gel-function-LinePlotClear"><function>LinePlotClear</function></link>
	    to put the graphing window into the line plot mode.
	    See also
	    <link linkend="gel-function-LinePlotWaitForClick"><function>LinePlotWaitForClick</function></link>.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotParametric"/>LinePlotParametric</term>
         <listitem>
          <synopsis>LinePlotParametric (xfonc,yfonc,...)</synopsis>
          <synopsis>LinePlotParametric (xfonc,yfonc,t1,t2,tinc)</synopsis>
          <synopsis>LinePlotParametric (xfonc,yfonc,t1,t2,tinc,x1,x2,y1,y2)</synopsis>
          <synopsis lang="en">LinePlotParametric (xfunc,yfunc,t1,t2,tinc,[x1,x2,y1,y2])</synopsis>
          <synopsis lang="en">LinePlotParametric (xfunc,yfunc,t1,t2,tinc,"fit")</synopsis>
          <para>Trace la courbe d'une fonction paramétrique. En premier viennent les fonctions de <varname>x</varname> et <varname>y</varname> puis, en option, les limites de <varname>t</varname> sous la forme <userinput>t1,t2,tinc</userinput> puis, en option, les limites de la fenêtre de tracé sous la forme <userinput>x1,x2,y1,y2</userinput>.</para>
	  <para lang="en">
	    If x and y limits are not
	    specified, then the currently set limits apply
	    (See <link linkend="gel-function-LinePlotWindow"><function>LinePlotWindow</function></link>).
	    If instead the string "fit" is given for the x and y limits, then the limits are the maximum extent of
	    the graph
          </para>
          <para>Le paramètre <link linkend="gel-function-LinePlotDrawLegends"><function>LinePlotDrawLegends</function></link> conditionne l'affichage de la légende.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-LinePlotWaitForClick"/>LinePlotWaitForClick</term>
         <listitem>
          <synopsis lang="en">LinePlotWaitForClick ()</synopsis>
          <para lang="en">
	    If in line plot mode, waits for a click on the line plot window
	    and returns the location of the click as a row vector.
	    If the window is closed
	    the function returns immediately with <constant>null</constant>.
	    If the window is not in line plot mode, it is put in it and shown
	    if not shown.
	    See also
	    <link linkend="gel-function-LinePlotMouseLocation"><function>LinePlotMouseLocation</function></link>.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PlotCanvasFreeze"/>PlotCanvasFreeze</term>
         <listitem>
          <synopsis lang="en">PlotCanvasFreeze ()</synopsis>
          <para lang="en">
		  Freeze drawing of the canvas plot temporarily.  Useful if you need to draw a bunch of elements
		  and want to delay drawing everything to avoid flicker in an animation.  After everything
		  has been drawn you should call <link linkend="gel-function-PlotCanvasThaw"><function>PlotCanvasThaw</function></link>.
          </para>
          <para lang="en">
		  The canvas is always thawed after end of any execution, so it will never remain frozen.  The moment
		  a new command line is shown for example the plot canvas is thawed automatically.  Also note that
		  calls to freeze and thaw may be safely nested.
          </para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PlotCanvasThaw"/>PlotCanvasThaw</term>
         <listitem>
          <synopsis lang="en">PlotCanvasThaw ()</synopsis>
          <para lang="en">
		  Thaw the plot canvas frozen by
		  <link linkend="gel-function-PlotCanvasFreeze"><function>PlotCanvasFreeze</function></link>
		  and redraw the canvas immediately.  The canvas is also always thawed after end of execution
		  of any program.
          </para>
	  <para lang="en">Version 1.0.18 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-PlotWindowPresent"/>PlotWindowPresent</term>
         <listitem>
          <synopsis lang="en">PlotWindowPresent ()</synopsis>
          <para lang="en">
		  Show and raise the plot window, creating it if necessary.
		  Normally the window is created when one of the plotting
		  functions is called, but it is not always raised if it
		  happens to be below other windows.  So this function is
		  good to call in scripts where the plot window might have 
		  been created before, and by now is hidden behind the
		  console or other windows.
          </para>
	  <para lang="en">Version 1.0.19 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SlopefieldClearSolutions"/>SlopefieldClearSolutions</term>
         <listitem>
          <synopsis>SlopefieldClearSolutions ()</synopsis>
          <para>Efface les solutions tracées par la fonction <link linkend="gel-function-SlopefieldDrawSolution"><function>SlopefieldDrawSolution</function></link>.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SlopefieldDrawSolution"/>SlopefieldDrawSolution</term>
         <listitem>
          <synopsis>SlopefieldDrawSolution (x, y, dx)</synopsis>
          <para>Lorsqu'un tracé de champ de directions est actif, dessine une solution avec les conditions initiales spécifiées. La méthode standard de Runge-Kutta est utilisée avec l'incrément <varname>dx</varname>. Les solutions restent affichées sur le graphe jusqu'à ce qu'un tracé différent soit affiché ou jusqu'à ce que vous appeliez la fonction <link linkend="gel-function-SlopefieldClearSolutions"><function>SlopefieldClearSolutions</function></link>. Vous pouvez aussi utiliser l'interface graphique pour tracer des solutions et indiquer des conditions initiales spécifiques avec la souris.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SlopefieldPlot"/>SlopefieldPlot</term>
         <listitem>
          <synopsis>SlopefieldPlot (fonc)</synopsis>
          <synopsis>SlopefieldPlot (fonc,x1,x2,y1,y2)</synopsis>
          <para>Trace un champ de directions. La fonction <varname>fonc</varname> doit accepter deux nombres réels <varname>x</varname> et <varname>y</varname> ou seulement un nombre complexe. En option, vous pouvez indiquer les limites de la fenêtre de tracé comme <varname>x1</varname>, <varname>x2</varname>, <varname>y1</varname>, <varname>y2</varname>. Si les limites ne sont pas indiquées alors les limites actuellement utilisées s'appliquent (consultez <link linkend="gel-function-LinePlotWindow"><function>LinePlotWindow</function></link>).</para>
          <para>Le paramètre <link linkend="gel-function-LinePlotDrawLegends"><function>LinePlotDrawLegends</function></link> conditionne l'affichage de la légende.</para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>SlopefieldPlot(`(x,y)=sin(x-y),-5,5,-5,5)</userinput>
</screen>
          </para>
         </listitem>
        </varlistentry>

	<varlistentry>
	 <term lang="en"><anchor id="gel-function-SurfacePlot"/>SurfacePlot</term>
         <listitem>
          <synopsis>SurfacePlot (fonc)</synopsis>
          <synopsis>SurfacePlot (fonc,x1,x2,y1,y2,z1,z2)</synopsis>
          <synopsis lang="en">SurfacePlot (func,x1,x2,y1,y2)</synopsis>
          <synopsis>SurfacePlot (func,[x1,x2,y1,y2,z1,z2])</synopsis>
          <synopsis lang="en">SurfacePlot (func,[x1,x2,y1,y2])</synopsis>
          <para lang="en">
	    Plot a surface function that takes either two arguments or a complex number.  First comes the function then optionally limits as <varname>x1</varname>, <varname>x2</varname>,
	    <varname>y1</varname>, <varname>y2</varname>,
	    <varname>z1</varname>, <varname>z2</varname>.  If limits are not
	    specified, then the currently set limits apply
	    (See <link linkend="gel-function-SurfacePlotWindow"><function>SurfacePlotWindow</function></link>).
	    Genius can only plot a single surface function at this time.
          </para>
          <para lang="en">
	    If the z limits are not specified then the maxima and minima of the function are used.
	  </para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>SurfacePlot(|sin|,-1,1,-1,1,0,1.5)</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlot(`(x,y)=x^2+y,-1,1,-1,1,-2,2)</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlot(`(z)=|z|^2,-1,1,-1,1,0,2)</userinput>
</screen>
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SurfacePlotClear"/>SurfacePlotClear</term>
         <listitem>
          <synopsis lang="en">SurfacePlotClear ()</synopsis>
          <para lang="en">
            Show the surface plot window and clear out functions and any other
            lines that were drawn.
          </para>
          <para lang="en">
	    Available in version 1.0.19 and onwards.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SurfacePlotData"/>SurfacePlotData</term>
         <listitem>
          <synopsis>SurfacePlotData (data)</synopsis>
          <synopsis>SurfacePlotData (data,label)</synopsis>
          <synopsis>SurfacePlotData (data,x1,x2,y1,y2,z1,z2)</synopsis>
          <synopsis>SurfacePlotData (data,label,x1,x2,y1,y2,z1,z2)</synopsis>
          <synopsis>SurfacePlotData (data,[x1,x2,y1,y2,z1,z2])</synopsis>
          <synopsis>SurfacePlotData (data,label,[x1,x2,y1,y2,z1,z2])</synopsis>
          <para lang="en">
		  Plot a surface from data.  The data is an n by 3 matrix whose
		  rows are the x, y and z coordinates.  The data can also be
		  simply a vector whose length is a multiple of 3 and so
		  contains the triples of x, y, z.  The data should contain at
		  least 3 points.
	  </para>
          <para lang="en">
		  Optionally we can give the label and also optionally the
		  limits.  If limits are not given, they are computed from
		  the data, <link linkend="gel-function-SurfacePlotWindow"><function>SurfacePlotWindow</function></link>
		  is not used, if you want to use it, pass it in explicitly.
		  If label is not given then empty label is used.
	  </para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>SurfacePlotData([0,0,0;1,0,1;0,1,1;1,1,3])</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlotData(data,"My data")</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlotData(data,-1,1,-1,1,0,10)</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlotData(data,SurfacePlotWindow)</userinput>
</screen>
          </para>
	  <para lang="en">
		  Here's an example of how to plot in polar coordinates,
		  in particular how to plot the function
		  <userinput>-r^2 * theta</userinput>:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>d:=null; for r=0 to 1 by 0.1 do for theta=0 to 2*pi by pi/5 do d=[d;[r*cos(theta),r*sin(theta),-r^2*theta]];</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlotData(d)</userinput>
</screen>
          </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SurfacePlotDataGrid"/>SurfacePlotDataGrid</term>
         <listitem>
          <synopsis>SurfacePlotDataGrid (data,[x1,x2,y1,y2])</synopsis>
          <synopsis>SurfacePlotDataGrid (data,[x1,x2,y1,y2,z1,z2])</synopsis>
          <synopsis>SurfacePlotDataGrid (data,[x1,x2,y1,y2],label)</synopsis>
          <synopsis>SurfacePlotDataGrid (data,[x1,x2,y1,y2,z1,z2],label)</synopsis>
          <para lang="en">
		  Plot a surface from regular rectangular data.
		  The data is given in a n by m matrix where the rows are the
		  x coordinate and the columns are the y coordinate.
		  The x coordinate is divided into equal n-1 subintervals
		  and y coordinate is divided into equal m-1 subintervals.
		  The limits <varname>x1</varname> and <varname>x2</varname>
		  give the interval on the x-axis that we use, and 
		  the limits <varname>y1</varname> and <varname>y2</varname>
		  give the interval on the y-axis that we use.
		  If the limits <varname>z1</varname> and <varname>z2</varname>
		  are not given they are computed from the data (to be
		  the extreme values from the data).
	  </para>
          <para lang="en">
		  Optionally we can give the label, if label is not given then
		  empty label is used.
	  </para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>SurfacePlotDataGrid([1,2;3,4],[0,1,0,1])</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlotDataGrid(data,[-1,1,-1,1],"My data")</userinput>
<prompt>genius&gt;</prompt> <userinput>d:=null; for i=1 to 20 do for j=1 to 10 do d@(i,j) = (0.1*i-1)^2-(0.1*j)^2;</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlotDataGrid(d,[-1,1,0,1],"half a saddle")</userinput>
</screen>
          </para>
	  <para lang="en">Version 1.0.16 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SurfacePlotDrawLine"/>SurfacePlotDrawLine</term>
         <listitem>
          <synopsis lang="en">SurfacePlotDrawLine (x1,y1,z1,x2,y2,z2,...)</synopsis>
          <synopsis lang="en">SurfacePlotDrawLine (v,...)</synopsis>
          <para lang="en">
	    Draw a line from <varname>x1</varname>,<varname>y1</varname>,<varname>z1</varname> to
	    <varname>x2</varname>,<varname>y2</varname>,<varname>z2</varname>.
	    <varname>x1</varname>,<varname>y1</varname>,<varname>z1</varname>,
	    <varname>x2</varname>,<varname>y2</varname>,<varname>z2</varname> can be replaced by an
	    <varname>n</varname> by 3 matrix for a longer polyline.
          </para>
          <para lang="en">
	    Extra parameters can be added to specify line color, thickness,
	    the plotting window, or legend.
	    You can do this by adding an argument string <userinput>"color"</userinput>, 
	    <userinput>"thickness"</userinput>,
	    <userinput>"window"</userinput>,
	    or <userinput>"legend"</userinput>, and after it specify
	    the color, the thickness, the window
	    as 6-vector, or the legend.
    	  </para>
    	  <para lang="en">
	    The color should be either a string indicating the common English word for the color
	    that GTK will recognize such as 
            <userinput>"red"</userinput>, <userinput>"blue"</userinput>, <userinput>"yellow"</userinput>, etc...
	    Alternatively the color can be specified in RGB format as
	    <userinput>"#rgb"</userinput>, <userinput>"#rrggbb"</userinput>, or
	    <userinput>"#rrrrggggbbbb"</userinput>, where the r, g, or b are hex digits of the red, green, and blue
	    components of the color.  Finally, since version 1.0.18, the color
	    can also be specified as a real vector specifying the red green and
	    blue components where the components are between 0 and 1, e.g. <userinput>[1.0,0.5,0.1]</userinput>.
    	  </para>
    	  <para lang="en">
	    The window should be given as usual as <userinput>[x1,x2,y1,y2,z1,z2]</userinput>, or
	    alternatively can be given as a string
	    <userinput>"fit"</userinput> in which case,
	    the x range will be set precisely and the y range will be set with
	    five percent borders around the line.
    	  </para>
    	  <para lang="en">
	    Finally, legend should be a string that can be used as the legend in the
	    graph.  That is, if legends are being printed.
          </para>
	  <para lang="en">
	  Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>SurfacePlotDrawLine(0,0,0,1,1,1,"color","blue","thickness",3)</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlotDrawLine([0,0,0;1,-1,2;-1,-1,-3])</userinput>
</screen>
          </para>
	  <para lang="en">
		  Available from version 1.0.19 onwards.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-SurfacePlotDrawPoints"/>SurfacePlotDrawPoints</term>
         <listitem>
          <synopsis lang="en">SurfacePlotDrawPoints (x,y,z,...)</synopsis>
          <synopsis lang="en">SurfacePlotDrawPoints (v,...)</synopsis>
          <para lang="en">
		  Draw a point at <varname>x</varname>,<varname>y</varname>,<varname>z</varname>.
		  The input can be an <varname>n</varname> by 3 matrix
		  for <varname>n</varname> different points.  This function has essentially the same
		  input as <link linkend="gel-function-SurfacePlotDrawLine">SurfacePlotDrawLine</link>.
          </para>
          <para lang="en">
	    Extra parameters can be added to specify line color, thickness,
	    the plotting window, or legend.
	    You can do this by adding an argument string <userinput>"color"</userinput>, 
	    <userinput>"thickness"</userinput>,
	    <userinput>"window"</userinput>, 
	    or <userinput>"legend"</userinput>, and after it specify
	    the color, the thickness, the window
	    as 6-vector, or the legend.
    	  </para>
    	  <para lang="en">
	    The color should be either a string indicating the common English word for the color
	    that GTK will recognize such as 
            <userinput>"red"</userinput>, <userinput>"blue"</userinput>, <userinput>"yellow"</userinput>, etc...
	    Alternatively the color can be specified in RGB format as
	    <userinput>"#rgb"</userinput>, <userinput>"#rrggbb"</userinput>, or
	    <userinput>"#rrrrggggbbbb"</userinput>, where the r, g, or b are hex digits of the red, green, and blue
	    components of the color.  Finally the color can also be specified as a real vector specifying the red green
	    and blue components where the components are between 0 and 1.
    	  </para>
    	  <para lang="en">
	    The window should be given as usual as <userinput>[x1,x2,y1,y2,z1,z2]</userinput>, or
	    alternatively can be given as a string
	    <userinput>"fit"</userinput> in which case,
	    the x range will be set precisely and the y range will be set with
	    five percent borders around the line.
    	  </para>
    	  <para lang="en">
	    Finally, legend should be a string that can be used as the legend in the
	    graph.  That is, if legends are being printed.
          </para>
	  <para lang="en">
	  Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>SurfacePlotDrawPoints(0,0,0,"color","blue","thickness",3)</userinput>
<prompt>genius&gt;</prompt> <userinput>SurfacePlotDrawPoints([0,0,0;1,-1,2;-1,-1,1])</userinput>
</screen>
          </para>
	  <para lang="en">
		  Available from version 1.0.19 onwards.
	  </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorfieldClearSolutions"/>VectorfieldClearSolutions</term>
         <listitem>
          <synopsis>VectorfieldClearSolutions ()</synopsis>
          <para>Efface les solutions dessinées par la fonction <link linkend="gel-function-VectorfieldDrawSolution"><function>VectorfieldDrawSolution</function></link>.</para>
	  <para lang="en">Version 1.0.6 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorfieldDrawSolution"/>VectorfieldDrawSolution</term>
         <listitem>
          <synopsis>VectorfieldDrawSolution (x, y, dt, tlong)</synopsis>
          <para>Lorsqu'un tracé de champ de vecteurs est actif, dessine une solution avec les conditions initiales spécifiées. La méthode standard de Runge-Kutta est utilisée avec l'incrément <varname>dt</varname> sur un intervalle de temps <varname>tlong</varname>. Les solutions restent affichées sur le graphe jusqu'à ce qu'un tracé différent soit affiché ou jusqu'à ce que vous appeliez la fonction <link linkend="gel-function-SlopefieldClearSolutions"><function>VectorfieldClearSolutions</function></link>. Vous pouvez aussi utiliser l'interface graphique pour tracer des solutions et indiquer des conditions initiales spécifiques avec la souris.</para>
	  <para lang="en">Version 1.0.6 onwards.</para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term lang="en"><anchor id="gel-function-VectorfieldPlot"/>VectorfieldPlot</term>
         <listitem>
          <synopsis>VectorfieldPlot (foncx, foncy)</synopsis>
          <synopsis>VectorfieldPlot (foncx, foncy, x1, x2, y1, y2)</synopsis>
          <para>Trace un champ de vecteurs à deux dimensions. La fonction <varname>funcx</varname> doit être la dérivée dx/dt du champ de vecteurs et la fonction <varname>funcy</varname> la dérivée dy/dt du champ de vecteurs. Les fonctions doivent accepter deux nombres réels <varname>x</varname> et <varname>y</varname> ou seulement un nombre complexe. Lorsque le paramètre <link linkend="gel-function-VectorfieldNormalized"><function>VectorfieldNormalized</function></link> est <constant>true</constant> (vrai) alors l'amplitude des vecteurs est normalisée. Seule la direction et non pas l'amplitude est tracée.</para>
	  <para>Vous pouvez spécifier, en option, les limites de la fenêtre de tracé sous la forme <varname>x1</varname>, <varname>x2</varname>, <varname>y1</varname>, <varname>y2</varname>, <varname>z1</varname>, <varname>z2</varname>. Si les limites ne sont pas indiquées alors les limites actuellement utilisées s'appliquent (consultez <link linkend="gel-function-LinePlotWindow"><function>LinePlotWindow</function></link>).</para>
          <para>Le paramètre <link linkend="gel-function-LinePlotDrawLegends"><function>LinePlotDrawLegends</function></link> conditionne l'affichage de la légende.</para>
          <para lang="en">
	    Examples:
          <screen lang="en"><prompt>genius&gt;</prompt> <userinput>VectorfieldPlot(`(x,y)=x^2-y, `(x,y)=y^2-x, -1, 1, -1, 1)</userinput>
</screen>
          </para>
         </listitem>
        </varlistentry>

      </variablelist>
    </sect1>

  </chapter>

  <!-- ============= GEL examples ============================= -->
  <chapter id="genius-gel-example-programs">
    <title>Exemple de programmes en GEL</title>

    <para lang="en">
Here is a function that calculates factorials:
<programlisting lang="en"><![CDATA[function f(x) = if x <= 1 then 1 else (f(x-1)*x)
]]></programlisting>
    </para>
    <para lang="en">
With indentation it becomes:
<programlisting lang="en"><![CDATA[function f(x) = (
  if x <= 1 then
    1
  else
    (f(x-1)*x)
)
]]></programlisting>
    </para>
    <para lang="en">
This is a direct port of the factorial function from the <application>bc</application> manpage. The syntax seems similar to <application>bc</application>, but different in that in GEL, the last expression is the one that is returned. Using the <literal>return</literal> function instead, it would be:
<programlisting lang="en"><![CDATA[function f(x) = (
  if (x <= 1) then return (1);
  return (f(x-1) * x)
)
]]></programlisting>
    </para>

    <para lang="en">
By far the easiest way to define a factorial function would be using
the product loop as follows.  This is not only the shortest and fastest,
but also probably the most readable version.
<programlisting lang="en">function f(x) = prod k=1 to x do k
</programlisting>
    </para>

    <para lang="en">
Here is a larger example, this basically redefines the internal
<link linkend="gel-function-ref"><function>ref</function></link> function to calculate the row echelon form of a
matrix.  The function <function>ref</function> is built in and much faster,
but this example demonstrates some of the more complex features of GEL.
<programlisting lang="en"><![CDATA[# Calculate the row-echelon form of a matrix
function MyOwnREF(m) = (
  if not IsMatrix(m) or not IsValueOnly(m) then
    (error("MyOwnREF: argument not a value only matrix");bailout);
  s := min(rows(m), columns(m));
  i := 1;
  d := 1;
  while d <= s and i <= columns(m) do (

    # This just makes the anchor element non-zero if at
    # all possible
    if m@(d,i) == 0 then (
      j := d+1;
      while j <= rows(m) do (
        if m@(j,i) == 0 then
          (j=j+1;continue);
        a := m@(j,);
        m@(j,) := m@(d,);
        m@(d,) := a;
        j := j+1;
        break
      )
    );
    if m@(d,i) == 0 then
      (i:=i+1;continue);
    
    # Here comes the actual zeroing of all but the anchor
    # element rows
    j := d+1;
    while j <= rows(m)) do (
      if m@(j,i) != 0 then (
        m@(j,) := m@(j,)-(m@(j,i)/m@(d,i))*m@(d,)
      );
      j := j+1
    );
    m@(d,) := m@(d,) * (1/m@(d,i));
    d := d+1;
    i := i+1
  );
  m
)
]]></programlisting>
    </para>

  </chapter>

  <!-- ============= Customization ============================ -->
  <chapter id="genius-prefs"> 
    <title>Paramètres</title> 

    <para lang="en">
      To configure <application>Genius Mathematics Tool</application>, choose
      <menuchoice><guimenu>Settings</guimenu>
      <guimenuitem>Preferences</guimenuitem></menuchoice>.
      There are several basic parameters provided by the calculator in addition
      to the ones provided by the standard library.  These control how the
      calculator behaves.
    </para>

    <note>
      <title>Modifications des paramètres avec GEL</title>
      <para>Beaucoup de paramètres dans Genius ne sont simplement que des variables globales qui peuvent être évaluées et auxquelles on peut attribuer des valeurs de la même manière que pour des variables normales. Consultez <xref linkend="genius-gel-variables"/> à propos de l'évaluation et <xref linkend="genius-gel-function-parameters"/> pour une liste des réglages qui peuvent être modifiés de cette façon.</para>
      <para lang="en">
As an example, you can set the maximum number of digits in a result to 12 by typing:
<programlisting lang="en">MaxDigits = 12
</programlisting>
      </para>
    </note>

    <sect1 id="genius-prefs-output"> 
      <title>Sortie</title> 
      <variablelist> 
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Maximum digits to output</guilabel>
      </term> 
	  <listitem>
		  <para lang="en">The maximum digits in a result (<link linkend="gel-function-MaxDigits"><function>MaxDigits</function></link>)</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Results as floats</guilabel>
      </term> 
	  <listitem>
		  <para lang="en">If the results should be always printed as floats (<link linkend="gel-function-ResultsAsFloats"><function>ResultsAsFloats</function></link>)</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Floats in scientific notation</guilabel>
      </term> 
	  <listitem>
		  <para lang="en">If floats should be in scientific notation (<link linkend="gel-function-ScientificNotation"><function>ScientificNotation</function></link>)</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Always print full expressions</guilabel>
      </term> 
	  <listitem>
		  <para lang="en">Should we print out full expressions for non-numeric return values (longer than a line) (<link linkend="gel-function-FullExpressions"><function>FullExpressions</function></link>)</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Use mixed fractions</guilabel>
      </term> 
	  <listitem>
		  <para lang="en">If fractions should be printed as mixed fractions such as "1 1/3" rather than "4/3". (<link linkend="gel-function-MixedFractions"><function>MixedFractions</function></link>)</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Display 0.0 when floating point number is less than 10^-x (0=never chop)</guilabel>
      </term> 
	  <listitem>
	  <para lang="en">How to chop output.  But only when other numbers nearby are large.
	   See the documentation of the parameter
          <link linkend="gel-function-OutputChopExponent"><function>OutputChopExponent</function></link>. </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
            <guilabel>Only chop numbers when another number is greater than 10^-x</guilabel>
      </term> 
	  <listitem>
		  <para lang="en">When to chop output.  This is set by the parameter <link linkend="gel-function-OutputChopWhenExponent"><function>OutputChopWhenExponent</function></link>.
	   See the documentation of the parameter
          <link linkend="gel-function-OutputChopExponent"><function>OutputChopExponent</function></link>. </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Remember output settings across sessions</guilabel>
      </term> 
	  <listitem>
        <para>Si les réglages concernant la sortie dans le cadre <guilabel>Options pour la sortie des nombres/expressions</guilabel> doivent être conservés pour la session suivante. Ne s'applique pas au cadre <guilabel>Options pour la sortie erreurs/information</guilabel>.</para>
	      <para>Si ce n'est pas coché, les réglages précédemment enregistrés ou ceux par défaut sont utilisés à chaque lancement de Genius. Notez que les paramètres sont enregistrés à la fin de la session donc si vous souhaitez modifier la valeur par défaut, cochez cette case, redémarrez Genius puis décochez-la à nouveau.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Display errors in a dialog</guilabel>
      </term> 
	  <listitem>
        <para lang="en">If set the errors will be displayed in a separate dialog, if
	unset the errors will be printed on the console.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Display information messages in a dialog</guilabel>
      </term> 
	  <listitem>
	<para lang="en">If set the information messages will be displayed in a separate
	dialog, if unset the information messages will be printed on the
	console.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Maximum errors to display</guilabel>
      </term> 
	  <listitem>
        <para lang="en">
	  The maximum number of errors to return on one evaluation
	  (<link linkend="gel-function-MaxErrors"><function>MaxErrors</function></link>).  If you set this to 0 then
	  all errors are always returned.  Usually if some loop causes
	  many errors, then it is unlikely that you will be able to make
	  sense out of more than a few of these, so seeing a long list
	  of errors is usually not helpful.
	  </para>
	  </listitem>
	</varlistentry>
      </variablelist> 

      <para>En plus de ces préférences, il existe d'autres préférences qui ne peuvent être modifiées qu'en les paramétrant dans l'espace de la console. Pour celles qui peuvent affecter la sortie, consultez <xref linkend="genius-gel-function-parameters"/>.</para>

      <variablelist> 
	<varlistentry>
	  <term lang="en"> 
	    <function>IntegerOutputBase</function>
      </term> 
	  <listitem>
        <para>La base utilisée pour afficher les entiers.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
	    <function>OutputStyle</function>
      </term> 
	  <listitem>
	<para lang="en">A string, can be <literal>"normal"</literal>,
<literal>"latex"</literal>, <literal>"mathml"</literal> or
<literal>"troff"</literal> and it will affect how matrices (and perhaps other
stuff) is printed, useful for pasting into documents.  Normal style is the
default human readable printing style of <application>Genius Mathematics Tool</application>.  The other styles are for
typesetting in LaTeX, MathML (XML), or in Troff.</para>
	  </listitem>
	</varlistentry>
      </variablelist> 
   </sect1> 

    <sect1 id="genius-prefs-precision"> 
      <title>Précision</title> 
      <variablelist> 
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Floating point precision</guilabel>
      </term> 
	  <listitem>
        <para lang="en">
	  The floating point precision in bits
	  (<link linkend="gel-function-FloatPrecision"><function>FloatPrecision</function></link>).
	  Note that changing this only affects newly computed quantities.
	  Old values stored in variables are obviously still in the old
	  precision and if you want to have them more precise you will have
	  to recompute them.  Exceptions to this are the system constants
	  such as <link linkend="gel-function-pi"><function>pi</function></link> or
	  <link linkend="gel-function-e"><function>e</function></link>.
	  </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Remember precision setting across sessions</guilabel>
      </term> 
	  <listitem>
        <para>Si le réglage de la précision doit être conservé pour la prochaine session. Si ce n'est pas coché, le paramétrage précédemment enregistré ou celui par défaut est utilisé à chaque lancement de Genius. Notez que les paramètres sont enregistrés à la fin de la session donc si vous souhaitez modifier la valeur par défaut, cochez cette case, redémarrez genius puis décochez-la à nouveau.</para>
	  </listitem>
	</varlistentry>
      </variablelist> 
    </sect1> 

    <sect1 id="genius-prefs-terminal"> 
      <title>Terminal</title> 

      <para>Le terminal se réfère à la console dans la zone de travail.</para>

      <variablelist> 
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Scrollback lines</guilabel>
      </term> 
	  <listitem>
        <para>Nombre de lignes d'historique dans le terminal.</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Font</guilabel>
      </term> 
	  <listitem>
        <para>La police à utiliser dans le terminal.</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Black on white</guilabel>
      </term> 
	  <listitem>
        <para>Si vous utilisez du noir sur blanc dans le terminal.</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Blinking cursor</guilabel>
      </term> 
	  <listitem>
        <para>Si le curseur dans le terminal doit clignoter lorsque le terminal possède le focus. Cela peut être parfois ennuyant et génère du trafic inutile si vous utilisez Genius à distance.</para>
	  </listitem>
	</varlistentry>
      </variablelist> 
    </sect1> 

    <sect1 id="genius-prefs-memory"> 
      <title>Mémoire</title> 
      <variablelist> 
	<varlistentry>
	  <term lang="en"> 
	    <guilabel>Maximum number of nodes to allocate</guilabel>
      </term> 
	  <listitem>
        <para lang="en">
	   Internally all data is put onto small nodes in memory.  This gives
	   a limit on the maximum number of nodes to allocate for
	   computations.  This limit avoids the problem of running out of memory
	   if you do something by mistake that uses too much memory, such
	   as a recursion without end.  This could slow your computer and make
	   it hard to even interrupt the program.
	  </para>
        <para>Une fois que la limite est atteinte, l'<application>Outil de maths Genius</application> vous demande si vous voulez interrompre le calcul ou si vous souhaitez continuer. Si vous continuez, aucune limite n'est appliquée et il est possible de saturer la mémoire de l'ordinateur. La limite s'applique à nouveau la prochaine fois que vous exécuterez un programme ou une expression dans la console indépendamment de votre réponse précédente.</para>
        <para>Régler la limite à zéro signifie qu'il n'y a aucune limite sur la quantité de mémoire utilisable par Genius.</para>
	  </listitem>
	</varlistentry>

      </variablelist> 
    </sect1> 

  </chapter>

<!-- ============= About ====================================== -->
  <chapter id="genius-about"> 
    <title>À propos de l'<application>Outil de maths Genius</application></title> 

    <para>L'<application>Outil de maths Genius</application> a été écrit par Jiří (George) Lebl (<email>jirka@5z.com</email>). L'historique de l'<application>Outil de maths Genius</application> commence à la fin de l'année 1997. C'était la première calculatrice pour GNOME, mais il a grossi au point de devenir bien plus qu'une simple calculatrice de bureau. Pour trouver plus d'informations à propos de l'<application>Outil de maths Genius</application>, visitez la <ulink url="http://www.jirka.org/genius.html" type="http">page Web de Genius</ulink>.</para>
    <para>Pour rapporter une anomalie ou émettre une suggestion concernant cette application ou ce manuel, envoyez un courriel à l'auteur ou à la liste de discussion (voir site Web).</para>

    <para lang="en"> This program is distributed under the terms of the GNU
      General Public license as published by the Free Software
      Foundation; either version 3 of the License, or (at your option)
      any later version. A copy of this license can be found at this
      <ulink url="http://www.gnu.org/copyleft/gpl.html" type="http">link</ulink>, or in the file
      COPYING included with the source code of this program. </para>

    <para lang="en">Jiří Lebl was during various parts of the development
      partially supported for the work by NSF grants DMS 0900885, 
      DMS 1362337,
      the University of Illinois at Urbana-Champaign,
      the University of California at San Diego, 
      the University of Wisconsin-Madison, and
      Oklahoma State University.  The software has
      been used for both teaching and research.</para>

  </chapter>

</book>