 supplied to
the <code>expand_to_tidy</code> function:</p>
<table class="table">
<colgroup>
<col width="57%">
<col width="42%">
</colgroup>
<thead><tr class="header">
<th align="right">argument to <code>expand_to_tidy</code>
</th>
<th align="left">identifies</th>
</tr></thead>
<tbody>
<tr class="odd">
<td align="right"><code>matnames</code></td>
<td align="left">Name of the input column of matrix names</td>
</tr>
<tr class="even">
<td align="right"><code>matvals</code></td>
<td align="left">Name of the inpu