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<title>Vectors - GNU Scientific Library -- Reference Manual</title>
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<h3 class="section">8.3 Vectors</h3>
<p><a name="index-vectors-852"></a><a name="index-stride_002c-of-vector-index-853"></a>
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>The <code>gsl_vector</code> structure contains five components, the
<dfn>size</dfn>, the <dfn>stride</dfn>, 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,
<pre class="example"> typedef struct
{
size_t size;
size_t stride;
double * data;
gsl_block * block;
int owner;
} gsl_vector;
</pre>
<p class="noindent">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>The functions for allocating and accessing vectors are defined in
<samp><span class="file">gsl_vector.h</span></samp>
<ul class="menu">
<li><a accesskey="1" href="Vector-allocation.html">Vector allocation</a>
<li><a accesskey="2" href="Accessing-vector-elements.html">Accessing vector elements</a>
<li><a accesskey="3" href="Initializing-vector-elements.html">Initializing vector elements</a>
<li><a accesskey="4" href="Reading-and-writing-vectors.html">Reading and writing vectors</a>
<li><a accesskey="5" href="Vector-views.html">Vector views</a>
<li><a accesskey="6" href="Copying-vectors.html">Copying vectors</a>
<li><a accesskey="7" href="Exchanging-elements.html">Exchanging elements</a>
<li><a accesskey="8" href="Vector-operations.html">Vector operations</a>
<li><a accesskey="9" href="Finding-maximum-and-minimum-elements-of-vectors.html">Finding maximum and minimum elements of vectors</a>
<li><a href="Vector-properties.html">Vector properties</a>
<li><a href="Example-programs-for-vectors.html">Example programs for vectors</a>
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