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<A HREF="#toc">Table of Contents</A><P>
 
<H2><A NAME="sect0" HREF="#toc0">Name</A></H2>
vector -  Vector data type for
Tcl 
<H2><A NAME="sect1" HREF="#toc1">Synopsis</A></H2>
<B>vector configure <I>option value ...</I></B> <P>
<B>vector create <I>vecName </I></B>?<I>vecName</I>...?
?<I>switches</I>?  <P>
<B>vector destroy <I>vecName </I></B>?<I>vecName</I>...? <P>
<B>vector expr <I>expression</I></B> <P>
<B>vector
names </B>?<I>pattern</I>...? <P>
<B>vector op</B> <I>operation vecName</I> ?<I>arg</I>?... 
<H2><A NAME="sect2" HREF="#toc2">Description</A></H2>
The <B>vector</B>
command creates a vector of floating point values.  The vector's components
can be manipulated in three ways: through a Tcl array variable, a Tcl command,
or the C API. 
<H2><A NAME="sect3" HREF="#toc3">Introduction</A></H2>
A vector is simply an ordered set of numbers. 
The components of a vector are real numbers, indexed by counting numbers.
<P>
Vectors are common data structures for many applications.  For example,
a graph may use two vectors to represent the X-Y coordinates of the data
plotted.  The graph will automatically be redrawn when the vectors are updated
or changed. By using vectors,  you can separate data analysis from the graph
widget.  This makes it easier, for example, to add data transformations,
such as splines.  It's possible to plot the same data to in multiple graphs,
where each graph presents a different view or scale of the data. <P>
You could
try to use Tcl's associative arrays as vectors.  Tcl arrays are easy to use.
 You can access individual elements randomly by specifying the index, or
the set the entire array by providing a list of index and value pairs for
each element.  The disadvantages of  associative arrays as vectors lie in
the fact they are implemented as hash tables. 
<UL>
<LI>There's no implied ordering
to the associative arrays.  If you used vectors for plotting, you would
want to insure the second component comes after the first, an so on.  This
isn't possible since arrays are actually hash tables.  For example, you can't
get a range of values between two indices.  Nor can you sort an array. </LI><LI>Arrays
consume lots of memory when the number of elements becomes large (tens
of thousands).  This is because each element's index and value are stored
as strings in the hash table. </LI><LI>The C programming interface is unwieldy.  Normally
with vectors, you would like to view the Tcl array as you do a C array,
as an array of floats or doubles.  But with hash tables, you must convert
both the index and value to and from decimal strings, just to access an
element in the array.  This makes it cumbersome to perform operations on
the array as a whole. </LI>
</UL>
<P>
The <B>vector</B> command tries to overcome these disadvantages
while still retaining the ease of use of Tcl arrays.  The <B>vector</B> command
creates both a new Tcl command and associate array which are linked to
the vector components.  You can randomly access vector components though
the elements of array.  Not all indices are generated for the array, so
printing the array (using the <B>parray</B> procedure) does not print out all
the component values.  You can use the Tcl command to access the array as
a whole.  You can copy, append, or sort vector using its command.  If you
need greater performance, or customized behavior, you can write your own
C code to manage vectors. 
<H2><A NAME="sect4" HREF="#toc4">Example</A></H2>
You create vectors using the <B>vector</B> command
and its <B>create</B> operation. <BR>
<CODE># Create a new vector. <BR>
vector create y(50)<BR>
</CODE>This creates a new vector named y.  It has fifty components, by default,
initialized to 0.0.  In addition, both a Tcl command and array variable,
both named y, are created.  You can use either the command or variable
to query or modify components of the vector. <BR>
<CODE># Set the first value. <BR>
set y(0) 9.25<BR>
puts "y has [y length] components"<BR>
</CODE>The array y can be used to read or set individual components of the vector.
 Vector components are indexed from zero.  The array index must be a number
less than the number of components.  For example, it's an error if you try
to set the 51st element of y. <BR>
<CODE># This is an error. The vector only has 50 components.<BR>
set y(50) 0.02<BR>
</CODE>You can also specify a range of indices using a colon (:) to separate the
first and last indices of the range. <BR>
<CODE># Set the first six components of y <BR>
set y(0:5) 25.2<BR>
</CODE>If you don't include an index, then it will default to the first and/or
last component of the vector. <BR>
<CODE># Print out all the components of y <BR>
puts "y = $y(:)"<BR>
</CODE>There are special non-numeric indices.  The index end, specifies the last
component of the vector.  It's an error to use this index if the vector is
empty (length is zero).  The index ++end can be used to extend the vector
by one component and initialize it to a specific  value.  You can't read
from the array using this index, though. <BR>
<CODE># Extend the vector by one component.<BR>
set y(++end) 0.02<BR>
</CODE>The other special indices are min and max.  They return the current
smallest and largest components of the vector.   <BR>
<CODE># Print the bounds of the vector<BR>
puts "min=$y(min) max=$y(max)"<BR>
</CODE>To delete components from a vector, simply unset the corresponding array
element. In the following example, the first component of y is deleted.
 All the remaining components of y will be moved down by one index as
the length of the vector is reduced by one. <BR>
<CODE># Delete the first component<BR>
unset y(0)<BR>
puts "new first element is $y(0)"<BR>
</CODE>The vector's Tcl command can also be used to query or set the vector. <BR>
<CODE># Create and set the components of a new vector<BR>
vector create x<BR>
x set { 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 }<BR>
</CODE>Here we've created a vector x without a initial length specification. In
this case, the length is zero.  The <B>set</B> operation resets the vector, extending
it and setting values for each new component.   <P>
There are several operations
for vectors.  The <B>range</B> operation lists the components of a vector between
two indices. <BR>
<CODE># List the components <BR>
puts "x = [x range 0 end]"<BR>
</CODE>You can search for a particular value using the <B>search</B> operation.  It returns
a list of indices of the components with the same value.  If no component
has the same value, it returns "". <BR>
<CODE># Find the index of the biggest component<BR>
set indices [x search $x(max)]<BR>
</CODE>Other operations copy, append, or sort vectors.  You can append vectors
or new values onto an existing vector with the <B>append</B> operation. <BR>
<CODE># Append assorted vectors and values to x<BR>
x append x2 x3 { 2.3 4.5 } x4<BR>
</CODE>The <B>sort</B> operation sorts the vector.  If any additional vectors are specified,
they are rearranged in the same order as the vector. For example, you could
use it to sort data points represented by x and y vectors. <BR>
<CODE># Sort the data points<BR>
x sort y<BR>
</CODE>The vector x is sorted while the components of y are  rearranged so
that the original x,y coordinate pairs are retained. <P>
The <B>expr</B> operation
lets you perform arithmetic on vectors.   The result is stored in the vector.
<BR>
<CODE># Add the two vectors and a scalar<BR>
x expr { x + y }<BR>
x expr { x * 2 }<BR>
</CODE>When a vector is modified, resized, or deleted, it may trigger call-backs
to notify the clients of the vector.  For example, when a vector used in
the <B>graph</B> widget is updated, the vector automatically notifies the widget
that it has changed.  The graph can then redrawn itself at the next idle
point.  By default, the notification occurs when Tk is next idle.  This way
you can modify the vector many times without incurring the penalty of the
graph redrawing itself for each change.  You can change this behavior using
the <B>notify</B> operation. <BR>
<CODE># Make vector x notify after every change<BR>
x notify always<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;...<BR>
# Never notify<BR>
x notify never<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;...<BR>
# Force notification now<BR>
x notify now<BR>
<P>
# Set Tcl callback for update of Tktable widget .t.<BR>
x notify callback {.t conf -padx [.t cget -padx]; .t reread}<BR>
<P>
</CODE>To delete a vector, use the <B>vector delete</B> command.   Both the vector and
its corresponding Tcl command are destroyed. <BR>
<CODE># Remove vector x<BR>
vector destroy x<BR>
</CODE>The psuedo vector <B>last</B> can be used at the end of an expression to implement
running totals. During execution it resolves to the result from the previous
vector element evaluation. <BR>
<CODE>vector create A(10)<BR>
vector create B(10)<BR>
vector create S(10)<BR>
vector create T(10)<BR>
S expr A+B<BR>
T expr S+last; # Running total<BR>

<H2><A NAME="sect5" HREF="#toc5"></CODE>Syntax</A></H2>
Vectors are created using the <B>vector create</B> operation.   Th <B>create</B>
operation can be invoked in one of three forms: 
<DL>

<DT><B>vector create <I>vecName</I></B> </DT>
<DD>This
creates a new vector <I>vecName</I> which initially has no components. </DD>

<DT><B>vector create
<I>vecName</I></B>(<I>size</I>) </DT>
<DD>This second form creates a new vector which will contain
<I>size</I> number of components.  The components will be indexed starting from
zero (0). The default value for the components is 0.0. </DD>

<DT><B>vector create <I>vecName</I></B>(<I>rows,columns</I>)
</DT>
<DD>This form allows creation of a matrix with the specified columns and <I>rows*columns</I>
elements. See the <I>matrix</I> section for more details. </DD>

<DT><B>vector create <I>vecName</I></B>(<I>first</I>:<I>last</I>)
</DT>
<DD>The last form creates a new vector of indexed <I>first</I> through <I>last</I>.  <I>First</I>
and <I>last</I> can be any integer value so long as <I>first</I> is less than <I>last</I>. </DD>
</DL>
<P>
Vector
names must start with a letter and consist of letters, digits, or underscores.
  <BR>
<CODE># Error: must start with letter<BR>
vector create 1abc<BR>
</CODE>You can automatically generate vector names using the "#auto" vector
name.  The <B>create</B> operation will generate a  unique vector name. <BR>
<CODE>set vec [vector create #auto]<BR>
puts "$vec has [$vec length] components"<BR>

<H3><A NAME="sect6" HREF="#toc6"></CODE>Vector Indices</A></H3>
Vectors are indexed by integers.  You can access the individual
vector components via its array variable or Tcl command.  The string representing
the index can be an integer, a numeric expression, a range, or a special
keyword. <P>
The index must lie within the current range of the vector, otherwise
an an error message is returned.  Normally the indices of a vector are start
from 0.  But you can use the <B>offset</B> operation to change a vector's indices
on-the-fly. <BR>
<CODE>puts $vecName(0)<BR>
vecName offset -5<BR>
puts $vecName(-5)<BR>
</CODE>When <I>matrix numcols</I> is &gt; 1, 2D indexes are supported using ROW,COL form.
<BR>
<CODE>vecName matrix numcols 3<BR>
puts vecName(0,2)<BR>
</CODE>You can also use numeric expressions as indices.  The result of the expression
must be an integer value.   <BR>
<CODE>set n 21<BR>
set vecName($n+3) 50.2<BR>
</CODE>The following special non-numeric indices are available: min, max, end,
and ++end.   <BR>
<CODE>puts "min = $vecName($min)"<BR>
set vecName(end) -1.2<BR>
</CODE>The indices min and max will return the minimum and maximum values
of the vector.  Also available are: prod,  sum,  and mean. The index
end returns the value of the  last component in the vector. he index end,0
returns the value of the  last row in column 0 of the vector. The index
++end is used to append new value onto the vector.  It automatically extends
the vector by numcols and sets its value. <BR>
<CODE># Append an new component to the end<BR>
set vecName(++end) 3.2<BR>
</CODE>A range of indices can be indicated by a colon (:).   <BR>
<CODE># Set the first six components to 1.0<BR>
set vecName(0:5) 1.0<BR>
</CODE>If no index is supplied the first or last component is assumed. <BR>
<CODE># Print the values of all the components<BR>
puts $vecName(:)<BR>

<H2><A NAME="sect7" HREF="#toc7"></CODE>Vector Operations</A></H2>

<DL>

<DT><B>vector configure <I>? -flush bool -watchunset bool -oldcreate
bool -maxsize int -novariable bool -nocommand bool?</I></B> </DT>
<DD>The <B>configure</B> operation
sets the default options used in creating vectors: these options are global
to the interpreter. The <I>-maxsize</I> option, when non-zero, limits creation size.
The <I>-oldcreate</I> enable the creation shortcut: <B>vector vec1 vec2 ...</B>. See the create
command for details on the others. By default, these are all disabled or
zero. </DD>
</DL>
</blockquote>

<DL>

<DT><B>vector create <I>vecName</I></B>?(<I>size</I>)?... ?<I>switches</I>?  </DT>
<DD>The <B>create</B> operation creates
a new vector <I>vecName</I>. The <I>size</I> may be an integer, a START:END range or ROW,COL
(see matrix). This creates both a Tcl command and array variable called
<I>vecName</I>.  The name <I>vecName</I> must be unique, so another Tcl command or array
variable can not already exist in the current scope.  You may access the
components of the vector using the  variable.  If you change a value in
the array, or unset an array element, the vector is updated to reflect
the changes.  When the variable <I>vecName</I> is unset, the vector and its Tcl
command are also destroyed. <P>
The vector has optional switches that affect
how the vector is created. They are as follows: <blockquote></DD>

<DT><B>-variable <I>varName</I></B> </DT>
<DD>Specifies
the name of a Tcl variable to be mapped to the vector. If the variable already
exists, it is first deleted, then recreated.  If <I>varName</I> is the empty string,
then no variable will be mapped. You can always map a variable back to the
vector using the vector's  <B>variable</B> operation. </DD>

<DT><B>-command <I>cmdName</I></B> </DT>
<DD>Maps a Tcl
command to the vector. The vector can be accessed using  <I>cmdName</I> and one
of the vector instance operations.   A Tcl command by that name cannot already
exist. If <I>cmdName</I> is the empty string, no command mapping will be made. </DD>

<DT><B>-watchunset
<I>boolean</I></B> </DT>
<DD>Indicates that the vector should automatically delete itself if
the variable associated with the vector is unset.  By default, the vector
will not be deleted.  This is different from previous releases.  Set <I>boolean</I>
to "true" to get the old behavior. </DD>

<DT><B>-flush <I>boolean</I></B> </DT>
<DD>Indicates that the vector
should automatically flush the cached variable elements which unsets all
the elements of the Tcl array variable associated with the vector, freeing
memory associated  with the variable. This includes both the hash table
and the hash keys. The down side is that this effectively flushes the caching
of vector elements in the array.  This means that the subsequent reads of
the array will require a decimal to string conversion. By default, flushing
is disabled. </DD>
</DL>
</blockquote>

<DL>

<DT><B>vector destroy <I>vecName</I></B> ?<I>vecName...</I>? </DT>
<DD>Destroy vectors. </DD>

<DT><B>vector expr
<I>expression</I></B> </DT>
<DD><blockquote>All binary operators take vectors as operands (remember that
numbers are treated as one-component vectors).The exact action of binary
operators depends upon the length of the second operand.  If the second
operand has only one component, then each element of the first vector operand
is computed by that value.  For example, the expression "x * 2" multiples
all elements of the vector x by 2.  If the second operand has more than
one component, both operands must be the same length.  Each pair of corresponding
elements are computed.  So "x + y" adds the the first components of x and
y together, the second, and so on. <P>
The valid operators are listed below,
grouped in decreasing order of precedence: </DD>

<DT><B>-  !</B> </DT>
<DD>Unary minus and logical
NOT.  The unary minus flips the sign of each component in the vector.  The
logical not operator returns a vector of whose values are 0.0 or 1.0.  For
each non-zero component 1.0 is returned, 0.0 otherwise. </DD>

<DT><B>^</B> </DT>
<DD>Exponentiation.   </DD>

<DT><B>*
 /  %</B> </DT>
<DD>Multiply, divide, remainder.   </DD>

<DT><B>+  -</B> </DT>
<DD>Add and subtract.   </DD>

<DT><B>&lt;&lt;  &gt;&gt;</B> </DT>
<DD>Left and
right shift.  Circularly shifts the values of the vector  </DD>

<DT><B>&lt;  &gt;  &lt;=  &gt;=</B> </DT>
<DD>Boolean
less, greater, less than or equal, and greater than or equal. Each operator
returns a vector of ones and zeros.  If the condition is true,  1.0 is the
component value, 0.0 otherwise. </DD>

<DT><B>==  !=</B> </DT>
<DD>Boolean equal and not equal. Each operator
returns a vector of ones and zeros.  If the condition is true,  1.0 is the
component value, 0.0 otherwise. </DD>

<DT><B>&amp;&amp;</B> </DT>
<DD>Logical AND.  Produces a 1 result if both
operands are non-zero, 0 otherwise. </DD>

<DT><B>||</B> </DT>
<DD>Logical OR.  Produces a 0 result if both
operands are zero, 1 otherwise. </DD>

<DT><I>x<B>?<I>y<B>:<I>z</I></B></I></B></I> </DT>
<DD>If-then-else, as in C. </DD>
</DL>
<P>
<P>
See the C manual
for more details on the results produced by each operator.  All of the binary
operators group left-to-right within the same precedence level.   <P>
Several
mathematical functions are supported for vectors.  Each of the following
functions invokes the math library function of the same name; see the manual
entries for the library functions for details on what they do.  The operation
is applied to all elements of the vector returning the results.   All functions
take a vector operand. If no vector operand is used in the call, the current
vector is assumed. eg. <BR>
<CODE>vector create aVec<BR>
aVec seq 0 100<BR>
aVec expr {2*abs(aVec)-1}<BR>
aVec length 100<BR>
aVec expr {2*row()}<BR>
vector expr {2*row()} ; # ERROR!<BR>
<BR>
</CODE><CODE><P>
<B>acos</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>cos</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>hypot</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>sinh</B> <BR>
<B>asin</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>cosh</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>log</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>sqrt</B> <BR>
<B>atan</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>exp</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>log10</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>tan</B>  <BR>
<B>ceil</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>floor</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>sin</B><tt> </tt>&nbsp;<tt> </tt>&nbsp;<B>tanh</B> <BR>
</CODE>Additional functions are: 
<DL>

<DT><B>abs</B> </DT>
<DD>Returns the absolute value of each component.
</DD>

<DT><B>random</B> </DT>
<DD>Returns a vector of non-negative values uniformly distributed  between
[0.0, 1.0) using <I>drand48</I>. The seed comes from the internal clock of the machine
or may be  set manual with the srandom function. </DD>

<DT><B>round</B> </DT>
<DD>Rounds each component
of the vector. </DD>

<DT><B>srandom</B> </DT>
<DD>Initializes the random number generator using <I>srand48</I>.
The high order 32-bits are set using the integral portion of the first 
vector component. All other components are ignored.  The low order 16-bits
 are set to an arbitrary value. </DD>
</DL>
<P>
The following functions return a single
value. 
<DL>

<DT><B>adev</B>  </DT>
<DD>Returns the average deviation (defined as the sum of the absolute
values  of the differences between component and the mean, divided by the
length of the vector). </DD>

<DT><B>kurtosis</B> </DT>
<DD>Returns the degree of peakedness (fourth
moment) of the vector. </DD>

<DT><B>length</B> </DT>
<DD>Returns the number of components in the vector.
</DD>

<DT><B>max</B> </DT>
<DD>Returns the vector's maximum value. </DD>

<DT><B>mean</B> </DT>
<DD>Returns the mean value of the
vector. </DD>

<DT><B>median</B> </DT>
<DD>Returns the median of the vector. </DD>

<DT><B>min</B> </DT>
<DD>Returns the vector's
minimum value. </DD>

<DT><B>q1</B> </DT>
<DD>Returns the first quartile of the vector. </DD>

<DT><B>q3</B> </DT>
<DD>Returns the
third quartile of the vector. </DD>

<DT><B>prod</B>  </DT>
<DD>Returns the product of the components.
</DD>

<DT><B>sdev</B>  </DT>
<DD>Returns the standard deviation (defined as the square root of the
variance) of the vector. </DD>

<DT><B>skew</B>  </DT>
<DD>Returns the skewness (or third moment) of
the vector.  This characterizes the degree of asymmetry of the vector about
the mean. </DD>

<DT><B>sum</B>  </DT>
<DD>Returns the sum of the components. </DD>

<DT><B>var</B> </DT>
<DD>Returns the variance
of the vector. The sum of the squared differences  between each component
and the mean is computed.  The variance is  the sum divided by the length
of the vector minus 1. </DD>
</DL>
<P>
This last set of functions returns a vector of the
same length as the argument. 
<DL>

<DT><B>invert</B> </DT>
<DD>Returns vector with elements in reversed
order. </DD>

<DT><B>norm</B>  </DT>
<DD>Scales the values of the vector to lie in the range [0.0..1.0].
</DD>

<DT><B>row</B>  </DT>
<DD>Psuedo function to get the current row. </DD>

<DT><B>sort</B> </DT>
<DD>Returns the vector components
sorted in ascending order. </DD>

<DT><B>shift(nVec,N)</B> </DT>
<DD>This is the only function taking
a second arg. It provides a version of <I>nvec</I> shifted by N places. When N is
a scalar or vector with only one element, shift fills vacant area with
0. Otherwise the second element of <I>nVec</I> is used for the fill value. One use
for this is providing running totals. </DD>
</DL>
</blockquote>

<DL>

<DT><B>vector names </B>?<I>pattern</I>? </DT>
<DD>Return names
of all defined vectors. </DD>
</DL>
</blockquote>

<DL>

<DT><B>vector op</B> <I>operation vecName</I> ?<I>arg</I>?... </DT>
<DD>Invoke instance
operation.  Supported operations are defined in the next section. Op is the
only way to invoke instance operation sub-commands when -command is defined
as empty in a vector.  It also allows writing vector code that is checkable
by a syntax checkers.  eg. <BR>
<P>
<CODE>vector create v1<BR>
v1 op append {1 2 3}<BR>
v1 op modify 1 2.1<BR>
<P>
</DD>
</DL>
</blockquote>

<H2><A NAME="sect8" HREF="#toc8"></CODE>Instance Operations</A></H2>
You can also use the vector's Tcl command to query or
modify it.  The general form is <BR>
<P>
<CODE><I>vecName <I>operation</I></I> ?<I>arg</I>?...<BR>
</CODE>Note this is equivalent to the form: <BR>
<P>
<CODE><B>vector op</B> <I>operation vecName</I> ?<I>arg</I>?...<BR>
</CODE>Both <I>operation</I> and its arguments determine the exact behavior of the command.
 The operations available for vectors are listed below. 
<DL>

<DT><I>vecName <B>+</B></I> <I>item</I> </DT>
<DD><I>vecName
<B>-</B></I> <I>item</I> <I>vecName <B>*</B></I> <I>item</I> <I>vecName <B>/</B></I> <I>item</I> Perform binary op and return result
as a list. </DD>

<DT><I>vecName <B>append</B></I> <I>item</I> ?<I>item</I>?... </DT>
<DD>Appends the component values from
<I>item</I> to <I>vecName</I>. <I>Item</I> can be either the name of a vector or a list of numeric
values. </DD>

<DT><I>vecName <B>binread</B></I> <I>channel</I> ?<I>length</I>? ?<I>switches</I>?  </DT>
<DD>Reads binary values
from a Tcl channel. Values are either appended to the end of the vector
or placed at a given index (using the <B>-at</B> option), overwriting existing
values.  Data is read until EOF is found on the channel or a specified number
of values <I>length</I>  are read (note that this is not necessarily the same
as the number of  bytes). The following switches are supported: <blockquote></DD>

<DT><B>-swap</B> </DT>
<DD>Swap
bytes and words.  The default endian is the host machine. </DD>

<DT><B>-at <I>index</I></B> </DT>
<DD>New values
will start at vector index <I>index</I>.  This will overwrite any current values.
</DD>

<DT><B>-format</B> <I>format</I> </DT>
<DD>Specifies the format of the data.  <I>Format</I> can be one of the
following: "i1", "i2", "i4", "i8", "u1, "u2", "u4", "u8", "r4", "r8", or
"r16".  The number indicates the number of bytes required for each value.
 The letter indicates the type: "i" for signed, "u" for unsigned, "r" or
real.  The default format is "r16". </DD>
</DL>
</blockquote>

<DL>

<DT><I>vecName <B>binwrite</B></I> <I>channel</I> ?<I>length</I>? ?<I>-at
index</I>?  </DT>
<DD>Like <B>binread</B>, but writes data. </DD>

<DT><I>vecName <B>clear</B></I>  </DT>
<DD>Clears the element
indices from the array variable associated with <I>vecName</I>.  This doesn't affect
the components of the vector.  By default, the number of entries in the
Tcl array doesn't match the number of components in the vector.  This is
because its too expensive to maintain decimal strings for both the index
and value for each component.  Instead, the index and value are saved only
when you read or write an element with a new index.  This command removes
the index and value strings from the array.  This is useful when the vector
is large. </DD>

<DT><I>vecName <B>delete</B></I> <I>index</I> ?<I>index</I>?... </DT>
<DD>Deletes the <I>index</I>th component from
the vector <I>vecName</I>. <I>Index</I> is the index of the element to be deleted.  This
is the same as unsetting the array variable element <I>index</I>.  The vector is
compacted after all the indices have been deleted. </DD>

<DT><I>vecName <B>dup</B></I> <I>destName</I>
 </DT>
<DD>Copies <I>vecName</I> to <I>destName</I>. <I>DestName</I> is the name of a destination vector.
 If a vector <I>destName</I> already exists, it is overwritten with the components
of <I>vecName</I>.  Otherwise a  new vector is created. </DD>

<DT><I>vecName <B>expr</B></I> <I>expression</I>
</DT>
<DD>Computes the expression and resets the values of the vector accordingly.
Both scalar and vector math operations are allowed.  All values in expressions
are either real numbers or names of vectors.  All numbers are treated as
one component vectors. </DD>

<DT><I>vecName <B>index</B></I> <I>index</I> ?<I>value</I>?... </DT>
<DD>Get/set individual vector
values.  This provides element updating when <I>-variable</I> is set to empty. </DD>

<DT><I>vecName
<B>insert</B></I> <I>index</I> <I>item</I> ?<I>item</I>?... </DT>
<DD>Inserts the component values from <I>item</I> to <I>vecName</I>
at <I>index</I> <I>Item</I> can be either the name of a vector or a list of numeric values.
</DD>

<DT><I>vecName <B>length</B></I> ?<I>newSize</I>? </DT>
<DD>Queries or resets the number of components in
<I>vecName</I>. <I>NewSize</I> is a number specifying the new size of the vector.  If <I>newSize</I>
is smaller than the current size of <I>vecName</I>, <I>vecName</I> is truncated.  If <I>newSize</I>
is greater, the vector is extended and the new components are initialized
to 0.0.  If no <I>newSize</I> argument is present, the current length of the vector
is returned. </DD>

<DT><I>vecName <B>matrix <I> ...</I></B></I> </DT>
<DD>Matrix provides a 2D array view into 1D data.
 It provides indexing operations in ROW,COL form making it suitable for
use with TkTable. Data storage remains unchanged: vectors are still just
a single long array. For example, here are two ways to create a 3 column
by 10 row matrix: <BR>
<P>
<CODE>vector create aVec(10,3)<BR>
vector create bVec(30)<BR>
bVec matrix numcols 3<BR>
set aVec(0,0) 99<BR>
set bVec(29,2) -99<BR>
aVec append {5 6 7}; # aVec now has 11 rows.<BR>
aVec append 1 2;     # Now aVec has 13 rows!<BR>
<P>
</CODE>Note that data is appended only in increments of numcols. Elements 0-2 make
up the first row, 3-5 the second, etc. Elements will appear only in increments
of the column size. <blockquote></DD>

<DT><I>vecName <B>matrix copy <I>dstcolumn</I></B></I> <I>srccolumn</I> <I>?srcVec?</I>   </DT>
<DD>Copy
a column of element values to column <I>dstcolumn</I> from <I>srccolumn</I>. If vector
<I>srcVec</I> is given, and not the same as <I>vecName</I>, the columns numbers must
be different. If the <I>srcVec</I> column is longer, <I>vecName</I> will be extended. If
shorter, remaining destination values are not overwritten. </DD>

<DT><I>vecName <B>matrix
delete <I>column</I></B></I>. </DT>
<DD>Delete elements in a column. Note that <B>numcols</B>, which must
be greater than 1, will be decremented. </DD>

<DT><I>vecName <B>matrix get <I>column</I></B></I> </DT>
<DD>Get the
element in a column:  this number must be less than <B>numcols</B>. Note that <B>numcols</B>
must be non-zero. </DD>

<DT><I>vecName <B>matrix insert <I>column</I></B></I> <I>?initvalue?</I> . </DT>
<DD>Insert a new
column of elements at column (default 0). The new column is initialized
with <I>initvalue</I>, or <I>0.0</I> if not specified. Note that <B>numcols</B> will be incremented.
</DD>

<DT><I>vecName <B>matrix multiply <I>srcVec</I></B></I> ?<I>dstVec</I>?  </DT>
<DD>Perform matrix multiplication
using <B>srcVec</B>, placing results either in <B>dstVec</B>, or returned as a list. The
numrows of <I>srcVec</I> must equal numcols in <I>vecName</I>.  One application for multiply
is coordinate transformation. </DD>

<DT><I>vecName <B>matrix numcols <I>?size?</I></B></I> </DT>
<DD>Get or set the
number of columns for a vectors data.  Values &gt;1 enable array variables to
accept 2d matrix indexes. For example with a numcols of 10, <B>$vec1(1,2)</B> refers
to the 13th element in the vector. A vectors size is also constrained to
multiples of numcols, as is it's offset. By default, numcols is 1. </DD>

<DT><I>vecName
<B>matrix numrows <I>?size?</I></B></I> </DT>
<DD>Get or set the length of rows in a columns for a
vector. By default, this is just the <I>vector length/numcols</I>. Setting this
value simply provides a convenient way to increase or decrease the vector
size by multiples of <I>numcols</I>. </DD>

<DT><I>vecName <B>matrix set <I>column</I></B></I> <I>?valuelist?</I> </DT>
<DD>Set
value  elements in a column:  this number must be less than <B>numcols</B>.  The
<I>valuelist</I> is a list values. If this list is shorter than the column, it's
last value is used for all remaining columns. The column gets set to the
values of <I>item</I>, or <I>0.0</I> by default. </DD>

<DT><I>vecName <B>matrix shift <I>column</I></B></I> <I>amount</I> ?<I>startoffset</I>?
</DT>
<DD>Shifts the values of a column by integer in<I>amount</I>.  A negative value shifts
upward. The <I>startoffset</I> indicates where to start shifting from. </DD>

<DT><I>vecName <B>matrix
sort <I>column</I></B></I> <I>?-reverse?</I> </DT>
<DD>Sort the vector by the given column. </DD>

<DT><I>vecName <B>matrix
transpose</B></I> </DT>
<DD>Transpose all columns with rows in matrix. Note that this is a
no-op if <B>numcols</B> is 1.  Otherwise, numcols will change to <B>vectorLength/numcols</B>.
</DD>
</DL>
</blockquote>

<DL>

<DT><I>vecName <B>merge</B></I> <I>srcName</I> ?<I>srcName</I>?... </DT>
<DD>Merges the named vectors into a single
vector.  The resulting  vector is formed by merging the components of each
source vector  one index at a time. </DD>

<DT><I>vecName <B>notify</B></I> ?<I>keyword</I>? ?<I>script</I>? </DT>
<DD>Queries
or controls how vector clients are notified of changes to the vector.  Also
allows setting a notifier callback. The exact behavior is determined by
<I>keyword</I>. <blockquote></DD>

<DT>always  </DT>
<DD>Indicates that clients are to be notified immediately
whenever the vector is updated. </DD>

<DT>never </DT>
<DD>Indicates that no clients are to
be notified. </DD>

<DT>whenidle </DT>
<DD>Indicates that clients are to be notified at the
next idle point whenever the vector is updated. </DD>

<DT>now </DT>
<DD>If any client notifications
is currently pending, they are notified immediately. </DD>

<DT>cancel </DT>
<DD>Cancels pending
notifications of clients using the vector. </DD>

<DT>pending </DT>
<DD>Returns 1 if a client
notification is pending, and 0 otherwise. </DD>

<DT>callback ?<I>script</I>? </DT>
<DD>Query or
set a Tcl callback script that is evaluated when a vector is updated. </DD>
</DL>
</blockquote>

<DL>

<DT><I>vecName
<B>populate</B></I> <I>destName</I> ?<I>density</I>? </DT>
<DD>Creates a vector <I>destName</I> which is a superset
of <I>vecName</I>. <I>DestName</I> will include all the components of <I>vecName</I>, in addition
the interval between each of the original components will contain a <I>density</I>
number of new components, whose values are evenly distributed between the
original components values.  This is useful for generating abscissas to
be interpolated along a spline. </DD>

<DT><I>vecName <B>range</B></I> <I>firstIndex</I> ?<I>lastIndex</I>?... </DT>
<DD>Returns
a list of numeric values representing the vector components between two
indices. Both <I>firstIndex</I> and <I>lastIndex</I> are  indices representing the range
of components to be returned. If  <I>lastIndex</I> is less than <I>firstIndex</I>, the
components are listed in reverse order. </DD>

<DT><I>vecName <B>search</B></I> <I>value</I> ?<I>value</I>?   </DT>
<DD>Searches
for a value or range of values among the components of <I>vecName</I>.  If one
<I>value</I> argument is given, a list of indices of the components which equal
<I>value</I> is returned.  If a second <I>value</I> is also provided, then the indices
of all components which lie within the range of the two values are returned.
If no components are found, then "" is returned. </DD>

<DT><I>vecName <B>set</B></I> <I>item</I> </DT>
<DD>Resets
the components of the vector to <I>item</I>. <I>Item</I> can be either a list of numeric
expressions or another vector. </DD>

<DT><I>vecName <B>seq</B></I> <I>start</I> ?<I>finish</I>? ?<I>step</I>? </DT>
<DD>Generates
a sequence of values starting with the value <I>start</I>. <I>Finish</I> indicates the
terminating value of the sequence.   The vector is automatically resized
to contain just the sequence. If three arguments are present, <I>step</I> designates
the interval.   <P>
With only two arguments (no <I>finish</I> argument), the sequence
will continue until the vector is filled.  With one argument, the interval
 defaults to 1.0. </DD>

<DT><I>vecName <B>sort</B></I> ?<B>-reverse</B>? ?<I>argName</I>?...   </DT>
<DD>Sorts the vector <I>vecName</I>
in increasing order.  If the <B>-reverse</B> flag is present, the vector is sorted
in decreasing order.  If other arguments <I>argName</I> are present, they are the
names of vectors which will be rearranged in the same manner as <I>vecName</I>.
 Each vector must be the same length as <I>vecName</I>. You could use this to sort
the x vector of a graph, while still retaining the same x,y coordinate
pairs in a y vector. </DD>

<DT><I>vecName <B>split</B></I> <I>dstName</I> ?<I>dstName</I>?... </DT>
<DD>Split the vector into
a multiple vectors.  The resulting  N vectors each contain the mod-Nth element
from source. </DD>

<DT><I>vecName <B>variable</B></I> <I>varName</I> </DT>
<DD>Maps a Tcl variable to the vector,
creating another means for  accessing the vector.  The variable <I>varName</I>
can't already  exist. This overrides any current variable mapping the vector
may have. </DD>
</DL>
</blockquote>

<H2><A NAME="sect9" HREF="#toc9">C Language API</A></H2>
You can create, modify, and destroy vectors from
C code, using  library routines.   You need to include the header file blt.h.
It contains the definition of the structure <B>Blt_Vector</B>, which represents
the vector.  It appears below. <BR>
<CODE>typedef struct {<BR>
    double *<I>valueArr</I>; <BR>
    int <I>numValues</I>;    <BR>
    int <I>arraySize</I>;    <BR>
    double <I>min</I>, <I>max</I>;  <BR>
} <B>Blt_Vector</B>;<BR>
</CODE>The field <I>valueArr</I> points to memory holding the vector components.  The
components are stored in a double precision array, whose size size is represented
by <I>arraySize</I>.  <I>NumValues</I> is the length of vector.  The size of the array
is always equal to or larger than the length of the vector.  <I>Min</I> and <I>max</I>
are minimum and maximum component values. 
<H2><A NAME="sect10" HREF="#toc10">Library Routines</A></H2>
The following
routines are available from C to manage vectors. Vectors are identified
by the vector name. <P>
<B>Blt_CreateVector</B>  <blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>int <B>Blt_CreateVector</B> (<I>interp</I>, <I>vecName</I>, <I>length</I>, <I>vecPtrPtr</I>)<BR>
<blockquote>Tcl_Interp *<I>interp</I>;<BR>
char *<I>vecName</I>;<BR>
int <I>length</I>;<BR>
Blt_Vector **<I>vecPtrPtr</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description: </DT>
<DD>Creates a new vector <I>vecName</I> with a length of <I>length</I>. <B>Blt_CreateVector</B>
creates both a new Tcl command and array  variable <I>vecName</I>.  Neither a command
nor variable named  <I>vecName</I> can already exist.  A pointer to the vector
is  placed into <I>vecPtrPtr</I>. </DD>

<DT>Results: </DT>
<DD>Returns TCL_OK if the vector is successfully
created.  If <I>length</I> is negative, a Tcl variable or command <I>vecName</I> already
exists, or memory cannot be allocated for the vector, then TCL_ERROR
is returned and <I>interp-&gt;result</I> will contain an error message. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_DeleteVectorByName</B>
 <blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>int <B>Blt_DeleteVectorByName</B> (<I>interp</I>, <I>vecName</I>)<BR>
<blockquote>Tcl_Interp *<I>interp</I>;<BR>
char *<I>vecName</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description: </DT>
<DD>Removes the vector <I>vecName</I>.  <I>VecName</I> is the name of a vector
which must already exist.  Both the Tcl command and array variable <I>vecName</I>
are destroyed.  All clients of the vector will be notified immediately that
the vector has been destroyed. </DD>

<DT>Results: </DT>
<DD>Returns TCL_OK if the vector is
successfully deleted.  If <I>vecName</I> is not the name a vector, then TCL_ERROR
is returned and <I>interp-&gt;result</I> will contain an error message. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_DeleteVector</B>
 <blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>int <B>Blt_DeleteVector</B> (<I>vecPtr</I>)<BR>
<blockquote>Blt_Vector *<I>vecPtr</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description: </DT>
<DD>Removes the vector pointed to by <I>vecPtr</I>.  <I>VecPtr</I> is a pointer
to a vector, typically set by <B>Blt_GetVector</B> or <B>Blt_CreateVector</B>.  Both the
Tcl command and array variable of the vector are destroyed.  All clients
of the vector will be notified immediately that the vector has been destroyed.
</DD>

<DT>Results: </DT>
<DD>Returns TCL_OK if the vector is successfully deleted.  If <I>vecName</I>
is not the name a vector, then TCL_ERROR is returned and <I>interp-&gt;result</I>
will contain an error message. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_GetVector</B>  <blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>int <B>Blt_GetVector</B> (<I>interp</I>, <I>vecName</I>, <I>vecPtrPtr</I>)<BR>
<blockquote>Tcl_Interp *<I>interp</I>;<BR>
char *<I>vecName</I>;<BR>
Blt_Vector **<I>vecPtrPtr</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description: </DT>
<DD>Retrieves the vector <I>vecName</I>.  <I>VecName</I> is the name of a vector
which must already exist.  <I>VecPtrPtr</I> will point be set to the address of
the vector. </DD>

<DT>Results: </DT>
<DD>Returns TCL_OK if the vector is successfully retrieved.
 If <I>vecName</I> is not the name of a vector, then TCL_ERROR is returned and
<I>interp-&gt;result</I> will contain an error message. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_ResetVector</B>  <P>
<blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>int <B>Blt_ResetVector</B> (<I>vecPtr</I>, <I>dataArr</I>, <BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;<I>numValues</I>, <I>arraySize</I>, <I>freeProc</I>)<BR>
<blockquote>Blt_Vector *<I>vecPtr</I>;<BR>
double *<I>dataArr</I>;<BR>
int *<I>numValues</I>;<BR>
int *<I>arraySize</I>;<BR>
Tcl_FreeProc *<I>freeProc</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description:  </DT>
<DD>Resets the components of the vector pointed to by <I>vecPtr</I>.
Calling <B>Blt_ResetVector</B> will trigger the vector to dispatch notifications
to its clients. <I>DataArr</I> is the array of doubles which represents the vector
data. <I>NumValues</I> is the number of elements in the array. <I>ArraySize</I> is the
actual size of the array (the array may be bigger than the number of values
stored in it). <I>FreeProc</I> indicates how the storage for the vector component
array (<I>dataArr</I>) was allocated.  It is used to determine how to reallocate
memory when the vector is resized or destroyed.  It must be TCL_DYNAMIC,
TCL_STATIC, TCL_VOLATILE, or a pointer to a function to free the memory
allocated for the vector array. If <I>freeProc</I> is TCL_VOLATILE, it indicates
that <I>dataArr</I> must be copied and saved.  If <I>freeProc</I> is TCL_DYNAMIC, it
indicates that <I>dataArr</I> was dynamically allocated and that Tcl should free
<I>dataArr</I> if necessary.  Static indicates that nothing should be done to
release storage for <I>dataArr</I>. </DD>

<DT>Results: </DT>
<DD>Returns TCL_OK if the vector is
successfully resized.  If <I>newSize</I> is negative, a vector <I>vecName</I> does not
exist, or memory cannot be allocated for the vector, then TCL_ERROR is
returned and <I>interp-&gt;result</I> will contain an error message. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_ResizeVector</B>
 <blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>int <B>Blt_ResizeVector</B> (<I>vecPtr</I>, <I>newSize</I>)<BR>
<blockquote>Blt_Vector *<I>vecPtr</I>;<BR>
int <I>newSize</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description: </DT>
<DD>Resets the length of the vector pointed to by <I>vecPtr</I> to <I>newSize</I>.
 If <I>newSize</I> is smaller than the current size of the vector, it is truncated.
 If <I>newSize</I> is greater, the vector is extended and the new components are
initialized to 0.0. Calling <B>Blt_ResetVector</B> will trigger the vector to
dispatch notifications. </DD>

<DT>Results: </DT>
<DD>Returns TCL_OK if the vector is successfully
resized.  If <I>newSize</I> is negative or memory can not be allocated for the
vector,  then TCL_ERROR is returned and <I>interp-&gt;result</I> will contain  an
error message. <P>
</DD>
</DL>
<P>
<B>Blt_VectorExists</B>  <blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>int <B>Blt_VectorExists</B> (<I>interp</I>, <I>vecName</I>)<BR>
<blockquote>Tcl_Interp *<I>interp</I>;<BR>
char *<I>vecName</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description: </DT>
<DD>Indicates if a vector named <I>vecName</I> exists in <I>interp</I>. </DD>

<DT>Results:
</DT>
<DD>Returns 1 if a vector <I>vecName</I> exists and 0 otherwise. </DD>
</DL>
</blockquote>
<P>
<P>
If your application
needs to be notified when a vector changes, it can allocate a unique <I>client
identifier</I> for itself.  Using this identifier, you can then register a call-back
to be made whenever the vector is updated or destroyed.  By default, the
call-backs are made at the next idle point.  This can be changed to occur
at the time the vector is modified.  An application can allocate more than
one identifier for any vector.  When the client application is done with
the vector, it should free the identifier. <P>
The call-back routine must of
the following type. <BR>
<blockquote><BR>
<CODE>typedef void (<B>Blt_VectorChangedProc</B>) (Tcl_Interp *<I>interp</I>, <BR>
<blockquote>ClientData <I>clientData</I>, Blt_VectorNotify <I>notify</I>);<BR>
</blockquote>
<BR>
</blockquote>
</PRE></CODE><I>ClientData</I> is passed to this routine whenever it is called.  You can use
this to pass information to the call-back.  The <I>notify</I>  argument indicates
whether the vector has been updated of destroyed. It is an enumerated type.
<BR>
<blockquote><BR>
<CODE>typedef enum {<BR>
    BLT_VECTOR_NOTIFY_UPDATE=1,<BR>
    BLT_VECTOR_NOTIFY_DESTROY=2<BR>
} <B>Blt_VectorNotify</B>;<BR>
<BR>
</blockquote>
<P>
</CODE><B>Blt_AllocVectorId</B> <blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>Blt_VectorId <B>Blt_AllocVectorId</B> (<I>interp</I>, <I>vecName</I>)<BR>
<blockquote>Tcl_Interp *<I>interp</I>;<BR>
char *<I>vecName</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description: </DT>
<DD>Allocates an client identifier for with the vector <I>vecName</I>.
This identifier can be used to specify a call-back which is triggered when
the vector is updated or destroyed. </DD>

<DT>Results: </DT>
<DD>Returns a client identifier
if successful.  If <I>vecName</I> is not the name of a vector, then NULL is returned
and <I>interp-&gt;result</I> will contain an error message. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_GetVectorById</B>  <blockquote>
<DL>

<DT>Synopsis:
</DT>
<DD><BR>
<CODE>int <B>Blt_GetVector</B> (<I>interp</I>, <I>clientId</I>, <I>vecPtrPtr</I>)<BR>
<blockquote>Tcl_Interp *<I>interp</I>;<BR>
Blt_VectorId <I>clientId</I>;<BR>
Blt_Vector **<I>vecPtrPtr</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description: </DT>
<DD>Retrieves the vector used by <I>clientId</I>.  <I>ClientId</I> is a valid
vector client identifier allocated by <B>Blt_AllocVectorId</B>. <I>VecPtrPtr</I> will
point be set to the address of the vector. </DD>

<DT>Results: </DT>
<DD>Returns TCL_OK if
the vector is successfully retrieved.   </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_SetVectorChangedProc</B> <blockquote>
<DL>

<DT>Synopsis:
</DT>
<DD><BR>
<CODE>void <B>Blt_SetVectorChangedProc</B> (<I>clientId</I>, <I>proc</I>, <I>clientData</I>);<BR>
<blockquote>Blt_VectorId <I>clientId</I>;<BR>
Blt_VectorChangedProc *<I>proc</I>;<BR>
ClientData *<I>clientData</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description:  </DT>
<DD>Specifies a call-back routine to be called whenever the vector
associated with <I>clientId</I> is updated or deleted.  <I>Proc</I> is a pointer to call-back
routine and must be of the type <B>Blt_VectorChangedProc</B>.  <I>ClientData</I> is a
one-word value to be passed to the routine when it is invoked. If <I>proc</I> is
NULL, then the client is not notified. </DD>

<DT>Results: </DT>
<DD>The designated call-back
procedure will be invoked when the vector is  updated or destroyed. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_FreeVectorId</B>
<blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>void <B>Blt_FreeVectorId</B> (<I>clientId</I>);<BR>
<blockquote>Blt_VectorId <I>clientId</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description:  </DT>
<DD>Frees the client identifier.  Memory allocated for the identifier
 is released.  The client will no longer be notified when the vector is
modified. </DD>

<DT>Results: </DT>
<DD>The designated call-back procedure will be no longer be
invoked when the vector is updated or destroyed. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_NameOfVectorId</B> <blockquote>
<DL>

<DT>Synopsis:
</DT>
<DD><BR>
<CODE>char *<B>Blt_NameOfVectorId</B> (<I>clientId</I>);<BR>
<blockquote>Blt_VectorId <I>clientId</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description:  </DT>
<DD>Retrieves the name of the vector associated with the client
identifier <I>clientId</I>.   </DD>

<DT>Results: </DT>
<DD>Returns the name of the vector associated
with <I>clientId</I>.  If <I>clientId</I> is not an identifier or the vector has been
destroyed,  NULL is returned. </DD>
</DL>
</blockquote>
<P>
<P>
<B>Blt_InstallIndexProc</B> <blockquote>
<DL>

<DT>Synopsis: </DT>
<DD><BR>
<CODE>void <B>Blt_InstallIndexProc</B> (<I>indexName</I>, <I>procPtr</I>)<BR>
<blockquote>char *<I>indexName</I>;<BR>
Blt_VectorIndexProc *<I>procPtr</I>;<BR>
</DD>
</DL>
</blockquote>

<DL>

<DT></CODE>Description:  </DT>
<DD>Registers a function to be called to retrieved the index
<I>indexName</I> from the vector's array variable.   <P>
typedef double Blt_VectorIndexProc(Vector
*vecPtr); <P>
The function will be passed a pointer to the vector.  The function
must return a double representing the value at the index. </DD>

<DT>Results: </DT>
<DD>The new
index is installed into the vector. </DD>
</DL>
</blockquote>
</blockquote>

<H2><A NAME="sect11" HREF="#toc11">C API Example</A></H2>
The following example opens
a file of binary data and stores it in an array of doubles. The array size
is computed from the size of the file. If the vector "data" exists, calling
<B>Blt_VectorExists</B>, <B>Blt_GetVector</B> is called to get the pointer to the vector.
Otherwise the routine <B>Blt_CreateVector</B> is called to create a new vector
and returns a pointer to it. Just like the Tcl interface, both a new Tcl
command and array variable are created when a new vector is created. It
doesn't make any difference what the initial size of the vector is since
it will be reset shortly. The vector is updated when <B>lt_ResetVector</B> is called.
 Blt_ResetVector makes the changes visible to the Tcl interface and other
vector clients (such as a graph widget). <P>
<BR>
<CODE>#include &lt;tcl.h&gt;<BR>
#include &lt;blt.h&gt;<tt> </tt>&nbsp;<tt> </tt>&nbsp;<tt> </tt>&nbsp;<tt> </tt>&nbsp;<tt> </tt>&nbsp;<tt> </tt>&nbsp;<tt> </tt>&nbsp;<tt> </tt>&nbsp;<BR>
Blt_Vector *vecPtr;<BR>
double *newArr;<BR>
FILE *f;<BR>
struct stat statBuf;<BR>
int numBytes, numValues;<BR>
<P>
f = fopen("binary.dat", "r");<BR>
fstat(fileno(f), &amp;statBuf);<BR>
numBytes = (int)statBuf.st_size;<BR>
<P>
/* Allocate an array big enough to hold all the data */<BR>
newArr = (double *)m<A HREF="alloc.numBytes">alloc(numBytes)</A>
;<BR>
numValues = numBytes / sizeof(double);<BR>
fread((void *)newArr, numValues, sizeof(double), f);<BR>
fclose(f);<BR>
<P>
if (Blt_VectorExists(interp, "data"))  {<BR>
    if (Blt_GetVector(interp, "data", &amp;vecPtr) != TCL_OK) {<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;return TCL_ERROR;<BR>
    }<BR>
} else {<BR>
   if (Blt_CreateVector(interp, "data", 0, &amp;vecPtr) != TCL_OK) {<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;return TCL_ERROR;<BR>
   }<BR>
}<BR>
/* <BR>
 * Reset the vector. Clients will be notified when Tk is idle. <BR>
 * TCL_DYNAMIC tells the vector to free the memory allocated <BR>
 * if it needs to reallocate or destroy the vector.<BR>
 */<BR>
if (Blt_ResetVector(vecPtr, newArr, numValues, numValues, <BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;TCL_DYNAMIC) != TCL_OK) {<BR>
    return TCL_ERROR;<BR>
}<BR>

<H2><A NAME="sect12" HREF="#toc12"></CODE>Incompatibilities</A></H2>
In previous versions, if the array variable isn't global
 (i.e. local to a Tcl procedure), the vector is automatically  destroyed
when the procedure returns. <BR>
<CODE>proc doit {} {<BR>
    # Temporary vector x<BR>
    vector x(10)<BR>
    set <A HREF="x.9">x(9)</A>
 2.0<BR>
      ...<BR>
}<BR>
<P>
</CODE>This has changed.  Variables are not automatically destroyed when their
variable is unset.  You can restore the old behavior by setting the "-watchunset"
switch. 
<H2><A NAME="sect13" HREF="#toc13"></CODE>Keywords</A></H2>
vector, graph, widget <P>

<HR><P>
<A NAME="toc"><B>Table of Contents</B></A><P>
<UL>
<LI><A NAME="toc0" HREF="#sect0">Name</A></LI>
<LI><A NAME="toc1" HREF="#sect1">Synopsis</A></LI>
<LI><A NAME="toc2" HREF="#sect2">Description</A></LI>
<LI><A NAME="toc3" HREF="#sect3">Introduction</A></LI>
<LI><A NAME="toc4" HREF="#sect4">Example</A></LI>
<LI><A NAME="toc5" HREF="#sect5">Syntax</A></LI>
<UL>
<LI><A NAME="toc6" HREF="#sect6">Vector Indices</A></LI>
</UL>
<LI><A NAME="toc7" HREF="#sect7">Vector Operations</A></LI>
<LI><A NAME="toc8" HREF="#sect8">Instance Operations</A></LI>
<LI><A NAME="toc9" HREF="#sect9">C Language API</A></LI>
<LI><A NAME="toc10" HREF="#sect10">Library Routines</A></LI>
<LI><A NAME="toc11" HREF="#sect11">C API Example</A></LI>
<LI><A NAME="toc12" HREF="#sect12">Incompatibilities</A></LI>
<LI><A NAME="toc13" HREF="#sect13">Keywords</A></LI>
</UL>
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