enience functions</strong>:</li>
</ol>
<ul>
<li>
<code><a href="reference/tr.html">tr()</a></code> - trace of a matrix</li>
<li>
<code><a href="reference/R.html">R()</a></code> - rank of a matrix</li>
<li>
<code><a href="reference/J.html">J()</a></code> - constant vector, matrix or array</li>
<li>
<code><a href="reference/len.html">len()</a></code> - Euclidean length of a vector or columns of a matrix</li>
<li>
<code><a href="reference/vec.html">vec()</a></code> - vectorize a matrix</li>
<li>
<code>Proj(y, 