t.htm#vector_expression">Vector Expression</a> .</li>
<li><code>E2</code> is a model of <a href=
"expression_concept.htm#vector_expression">Vector Expression</a> .</li>
</ul>
<h4>Preconditions</h4>
<p>None.</p>
<h4>Complexity</h4>
<p>Quadratic depending from the size of the vector expressions.</p>
<h4>Examples</h4>
<pre>
#include &lt;boost/numeric/ublas/matrix.hpp&gt;
#include &lt;boost/numeric/ublas/io.hpp&gt;

int main () {
    using namespace boost::numeric::ublas;
    vector&lt;double&gt; v1 (3), v2 (3)