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<a name="Vectors"></a>
<div class="header">
<p>
Next: <a href="Matrices.html#Matrices" accesskey="n" rel="next">Matrices</a>, Previous: <a href="Blocks.html#Blocks" accesskey="p" rel="previous">Blocks</a>, Up: <a href="Vectors-and-Matrices.html#Vectors-and-Matrices" accesskey="u" rel="up">Vectors and Matrices</a> &nbsp; [<a href="Function-Index.html#Function-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Vectors-1"></a>
<h3 class="section">8.3 Vectors</h3>
<a name="index-vectors-1"></a>
<a name="index-stride_002c-of-vector-index"></a>

<p>Vectors are defined by a <code>gsl_vector</code> structure which describes a
slice of a block.  Different vectors can be created which point to the
same block.  A vector slice is a set of equally-spaced elements of an
area of memory.
</p>
<a name="index-gsl_005fvector"></a>
<p>The <code>gsl_vector</code> structure contains five components, the
<em>size</em>, the <em>stride</em>, a pointer to the memory where the elements
are stored, <var>data</var>, a pointer to the block owned by the vector,
<var>block</var>, if any, and an ownership flag, <var>owner</var>.  The structure
is very simple and looks like this,
</p>
<div class="example">
<pre class="example">typedef struct
{
  size_t size;
  size_t stride;
  double * data;
  gsl_block * block;
  int owner;
} gsl_vector;
</pre></div>

<p>The <var>size</var> is simply the number of vector elements.  The range of
valid indices runs from 0 to <code>size-1</code>.  The <var>stride</var> is the
step-size from one element to the next in physical memory, measured in
units of the appropriate datatype.  The pointer <var>data</var> gives the
location of the first element of the vector in memory.  The pointer
<var>block</var> stores the location of the memory block in which the vector
elements are located (if any).  If the vector owns this block then the
<var>owner</var> field is set to one and the block will be deallocated when the
vector is freed.  If the vector points to a block owned by another
object then the <var>owner</var> field is zero and any underlying block will not be
deallocated with the vector.
</p>
<p>The functions for allocating and accessing vectors are defined in
<samp>gsl_vector.h</samp>
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="Vector-allocation.html#Vector-allocation" accesskey="1">Vector allocation</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Accessing-vector-elements.html#Accessing-vector-elements" accesskey="2">Accessing vector elements</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Initializing-vector-elements.html#Initializing-vector-elements" accesskey="3">Initializing vector elements</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Reading-and-writing-vectors.html#Reading-and-writing-vectors" accesskey="4">Reading and writing vectors</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Vector-views.html#Vector-views" accesskey="5">Vector views</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Copying-vectors.html#Copying-vectors" accesskey="6">Copying vectors</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Exchanging-elements.html#Exchanging-elements" accesskey="7">Exchanging elements</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Vector-operations.html#Vector-operations" accesskey="8">Vector operations</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Finding-maximum-and-minimum-elements-of-vectors.html#Finding-maximum-and-minimum-elements-of-vectors" accesskey="9">Finding maximum and minimum elements of vectors</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Vector-properties.html#Vector-properties">Vector properties</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Example-programs-for-vectors.html#Example-programs-for-vectors">Example programs for vectors</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
</table>

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Next: <a href="Matrices.html#Matrices" accesskey="n" rel="next">Matrices</a>, Previous: <a href="Blocks.html#Blocks" accesskey="p" rel="previous">Blocks</a>, Up: <a href="Vectors-and-Matrices.html#Vectors-and-Matrices" accesskey="u" rel="up">Vectors and Matrices</a> &nbsp; [<a href="Function-Index.html#Function-Index" title="Index" rel="index">Index</a>]</p>
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