eta=factor(c(1,2,3,NA)))</code> would fit the first three fixed-effect parameters of the conditional model and fix the fourth parameter to its starting value. In general, users will probably want to use <code>start</code> to specify non-default starting values for fixed parameters. See <code><a href="https://rdrr.io/pkg/TMB/man/MakeADFun.html" class="external-link">MakeADFun</a></code> for more details.</p></dd>


<dt>sparseX</dt>
<dd><p>a named logical vector containing (possibly) elements named "cond", "z