 value is <code>sqrt(.Machine$double.eps)</code>.</p></dd>


<dt>weights</dt>
<dd><p>weights, as in <code>glm</code>. Not automatically scaled to have sum 1.</p></dd>


<dt>offset</dt>
<dd><p>offset for conditional model (only).</p></dd>


<dt>contrasts</dt>
<dd><p>an optional list, e.g., <code>list(fac1="contr.sum")</code>. See the <code>contrasts.arg</code> of <code><a href="https://rdrr.io/r/stats/model.matrix.html" class="external-link">model.matrix.default</a></code>.</p></dd>


<dt>na.action</dt>
<dd>