the <code>matrix_column</code>.</td>
</tr>

<tr>
<td><code>iterator end ()</code> </td>
<td>Returns a <code>iterator</code> pointing to the end of the
<code>matrix_column</code>.</td>
</tr>

<tr>
<td><code>const_reverse_iterator rbegin () const</code></td>
<td>Returns a <code>const_reverse_iterator</code> pointing to the
beginning of the reversed <code>matrix_column</code>.</td>
</tr>

<tr>
<td><code>const_reverse_iterator rend () const</code></td>
<td>Returns a <code>const_reverse_iterator</code> pointing 