y</code> has a capacity up to which new element can be inserted.
If <code>insert</code> would cause the size of the <code>map_array</code> to exceeds its capactity then it is <strong>reallocated</strong>. Iterators and reference are invalidated.
The capacity can be directly control using the <code>reserve</code> member function.
</p>
<h4>Example</h4>
<pre>
#include &lt;boost/numeric/ublas/storage_sparse.hpp&gt;

int main () {
    using namespace boost::numeric::ublas;
    map_array&lt;int, double&gt; a (3);