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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<head>
<title>Surface Evolver Documentation</title>
</head>
<body>
<a name="miscellaneous top"></a>
<center>
<h1><a href="http://www.susqu.edu/facstaff/b/brakke/evolver/evolver.htm">
Surface Evolver</a> Documentation</h1>
</center>
<a href="evolver.htm#doc top">Back to top of Surface Evolver documentation.</a>
<a href="index.htm">Index.</a>
<center><h2> Some miscellaneous topics </h2></center>
<hr>
<!--NewPage-->
<a name="options"></a>
<h2>Command line options</h2>
<p>The syntax for starting the Evolver from the system command prompt is:
</p>
<pre>evolver [-f<i>filename</i>] [-a-] [-d] [-e] [-i] [-m] [-p<i>n</i>] [-q] [-Q] [-w] [-x] [-y] [<em>datafile</em>]
</pre>
<p>The current directory and <a HREF="install.htm#EVOLVERPATH">EVOLVERPATH</a>
will be searched for datafile. If the datafile is not found, then a new
search with extension <tt>.fe</tt> is done.
Wildcard matching is in effect
on some systems (Windows, linux, maybe others), but be very careful when
using wildcards since there can be unexpected matches.
If the datafile still not found, or the
datafile is not given on the command line, then the user will be prompted.
Options: </p>
<dl>
<dt>
<a name="no autoconvert option"></a>
-a-
</dt>
<dd>
Do not enable automatic conversion to named methods and quantities mode when a
situation requiring it arises.
</dd>
<dt>
<a name="debug option"></a>
-d </dt>
<dd>Prints YACC debugging trace as datafile is parsed. May be helpful if
you can't figure out why your datafile doesn't get read in properly AND
you know YACC.
</dd>
<dt><a name="file option"></a>
-f<i>filename</i> </dt>
<dd>Specifies the name of a file to be used as command input after the
datafile is read. At the end of this file, input reverts to standard input.
The effect is the same as redirecting input from the file, except that
-f will echo commands to the screen and revert to standard input at the
end. Also note that errors will cause input to revert to standard input.
</dd>
<dt><a name="echo option"></a>
-e</dt>
<dd>
Echo input. Meant for echoing commands of piped input to
screen so the user can follow what is going on in case Evolver is being
controlled by another process.
</dd>
<dt><a name="no renumbering option"></a>
-i</dt>
<dd> Keeps elements numbers as listed in the datafile, instead
of renumbering them consecutively. The same effect can be achieved
by putting the keyword <b>keep_originals</b> in the top of the datafile.
</dd>
<dt><a name="memory debug option"></a>
-m </dt>
<dd>Turn memory debugging on at start of program. Same effect as Evolver
<a HREF="toggle.htm#memdebug">memdebug</a> command.
</dd>
<dt><a name="multiprocessor option"></a>
-p<i>n</i> </dt>
<dd>Forces use of n processes for an Evolver compiled in multi-processor
mode. <i>n</i> may be larger or smaller than the physically available number of
processors. The default is 1. This option should be regarded as experimental;
there is still too much overhead for it to be useful usually.
</dd>
<dt><a name="named quantities option"></a>
-q </dt>
<dd>Convert everything to <a HREF="quants.htm">named quantities</a> internally.
There are a few things for which no quantities exist yet; they will produce
error messages.
</dd>
<dt><a name="quietload option"></a>
-Q </dt>
<dd>Suppresses echoing of <tt>read</tt> section of datafile, and of
files input with the <tt>read</tt> command; same as
<a href="toggle.htm#quietload">quietload</a> toggle.
</dd>
<dt>
<a name="exit warning option"></a>
-w </dt>
<dd>Causes Evolver to exit whenever a warning occurs. Meant to be used when
Evolver is run in a shell script.
</dd>
<dt><a name="exit error option"></a>
-x </dt>
<dd>Causes Evolver to exit whenever an error occurs. Meant to be used when
Evolver is run in a shell script, so that Evolver doesn't get hung up waiting
for input in response to an error.
<dt><a name="break after warning option"></a>
-y </dt>
<dd>Causes Evolver to cease execution of commands and return to command
prompt after any warning message. Same effect as
<a href="toggle.htm#break_after_warning">break_after_warning</a>
runtime toggle.
</dd>
</dl>
<p>
<hr><h2><a name="bugs">
Bugs</a></h2>
Bug reports should be submitted by email to <tt>brakke@susqu.edu</tt>.
Please include the Evolver version number, a description of the problem,
the initial data file, and the sequence of commands necessary to reproduce
the problem.
<hr><h2><a name="newsletters">
Evolver Newsletters</a></h2>
The group of Surface Evolver users has grown large enough that I have
started a newsletter. Contents include announcement of new versions and
latest features, bibliography, and anything else anybody would like to
contribute. If you would like to be on the mailing list, send your email
address to <tt>brakke@susqu.edu</tt>. <p>
<p>Back issues: </p>
<ul>
<li><a HREF="news_01.htm">Newsletter 1</a> </li>
<li><a HREF="news_02.htm">Newsletter 2</a> </li>
<li><a HREF="news_03.htm">Newsletter 3</a> </li>
<li><a HREF="news_04.htm">Newsletter 4</a> </li>
<li><a HREF="news_05.htm">Newsletter 5</a> </li>
<li><a HREF="news_06.htm">Newsletter 6</a> </li>
<li><a HREF="news_07.htm">Newsletter 7</a> </li>
<li><a HREF="news_08.htm">Newsletter 8</a> </li>
<li><a HREF="news_09.htm">Newsletter 9</a> </li>
<li><a HREF="news_10.htm">Newsletter 10</a> </li>
<li><a HREF="news_11.htm">Newsletter 11</a> </li>
<li><a HREF="news_12.htm">Newsletter 12</a> </li>
<li><a HREF="news_13.htm">Newsletter 13</a> </li>
<li><a HREF="news_14.htm">Newsletter 14</a> </li>
<li><a HREF="news_15.htm">Newsletter 15</a> </li>
<li><a HREF="news_16.htm">Newsletter 16</a> </li>
<li><a HREF="news_17.htm">Newsletter 17</a> </li>
<li><a HREF="news_18.htm">Newsletter 18</a> </li>
<li><a HREF="news_19.htm">Newsletter 19</a> </li>
<li><a HREF="news_20.htm">Newsletter 20</a> </li>
</ul>
<p>
<hr><h2><a name="error handling">
Error handling</a></h2>
When the Surface Evolver detects an error, it prints an error message
and tries to take appropriate action. If the <a HREF="#options">-x</a>
command line option was given when Evolver was started, then Evolver exits
immediately with a nonzero error code. This is useful when running Evolver
from shell scripts. There are several categories of
errors: <p>
<ul>
<li><tt>WARNING</tt> - Something has happened that you should know about,
but Evolver proceeds normally after printing the message. </li>
<li><tt>SYNTAX ERROR</tt> - The parser has detected an error. Recent input
up to the detection of the error is printed, but the actual problem may
be earlier.
</li>
<li><tt>DATAFILE ERROR</tt> - There is an error in the datafile being read
in. Evolver attempts to recover by skipping to the next recognizable part
of the datafile, but will abandon the datafile after 5 such errors.
The surface data that was read in is available for your inspection,
but it probably forms an inconsistent surface and you should not try
to evolve it.</li>
<li><tt>ERROR</tt> - This is an error encountered during the execution
of a command. The command is abandoned and Evolver returns to the main
prompt. The actions of the command are not undone.</li>
<li><tt>FATAL ERROR</tt> - An error from which recovery is impossible.
Evolver exits immediately. </li>
</ul>
<p>
<hr><h2><a name="initialization">
Surface initialization</a></h2>
Whenever the Surface Evolver loads a new surface, either on startup
or in response to the <a HREF="single.htm#q">q</a> or <a HREF="commands.htm#load">load</a>
commands, the following actions occur: <p>
<ul>
<li>Any previous surface has all memory deallocated. All user-defined variables
and commands are deleted, including any currently executing commands. </li>
<li>Internal variables are initialized to default values. </li>
<li>The datafile is read in. </li>
<li>In the <a HREF="model.htm#soapfilm model">soapfilm model</a>, any nontriangular
face is divided into triangles by creating a vertex in the center and making
edges from the center to the vertices. </li>
<li>In the <a HREF="model.htm#soapfilm model">soapfilm model</a>, the order
of facets around each edge is determined geometrically. </li>
<li>Vertices are projected to any <a HREF="constrnt.htm">level set constraints</a>.
</li>
<li>Checks as described for the <a HREF="single.htm#C">C</a> command are
done. </li>
<li>Initial areas, energies, and volumes are calculated. </li>
<li>The <a HREF="graphics.htm#view matrix">viewing matrix</a> is reset
to center the object in the graphics window. </li>
<li>If any graphics are active, the new surface is drawn. </li>
<li>The main command prompt is started. </li>
</ul>
<p>
<hr><h2><a name="interrupts">
Interrupting execution</a></h2>
Evolver operation may be interrupted with the standard keyboard interrupt,
CTRL-C usually (SIGINT for you unix gurus). During repeated operations,
this will set a flag which is checked at the end of each loop. Repetition
will cease after the current step and control will return to the main prompt.
If you give a second interrupt before the loop has ended, Evolver will
abort the command and return to the main prompt. Beware that this may leave
the surface in an inconsistent state if surface topology changing operations
were going on. An immediate abort will also happen if an interrupt is received
outside a loop. If Evolver receives SIGTERM (say from the unix kill command),
it will dump to the default
<a href="commands.htm#dump">dump</a> file and exit. This is useful for stopping
a background Evolver running a script. The same thing will happen with
SIGHUP, so losing a modem connection will save the current surface.
<p>
Note: In Microsoft Windows, the second interrupt doesn't do anything much
since Windows creates a separate thread to handle the interrupt, and
I can't find any way to force the offending thread to stop and longjmp
back to where it should. So if the Evolver is really, really stuck,
you may just have to kill the whole program.
<hr><h2><a name="parallel">
Parallel computation</a></h2>
Parallel versions of the Surface Evolver are available for several
types of systems, but these are experimental and not very useful. <p>
<ul>
<li><a HREF="#SGI parallel">Silicon Graphics</a> </li>
<li><a HREF="MPI_evolver.htm">MPI </a></li>
</ul>
<h3><a name="SGI parallel">
Silicon Graphics parallel version
</a></h3>
<p>Silicon Graphics systems with multiple processors may run a version
that will use some or all processor by including <tt>-DSGI_MULTI</tt> in
<tt>CFLAGS</tt> in Makefile. This version will run fine with one processor,
also. Currently, the only calculations done in parallel are the "<a HREF="quants.htm">named
quantities</a>", so it is best to start Evolver with the <a HREF="#options">-q</a>
option. The number <i>n</i> of processes actually done in parallel can
be controlled with the <a HREF="#options"><tt>-p</tt><i>n</i></a> command
line option. It will slow things down to use more processes than are physically
available, but it is possible to run multiple processes on a single-processor
system. SGI's use shared memory, so no message passing is necessary, and
this version runs pretty well.
<hr>
<hr><a HREF="evolver.htm#doc top">Back to top of Surface Evolver documentation.</a>
<a href="index.htm">Index.</a>
<hr>
<a href="http://www.susqu.edu/facstaff/b/brakke/">
Author's home page.</a>
</body>
</html>
|
