oposal covariance for the MCMC samples by option <tt>options.qcov</tt> below.</p><pre class="codeinput">J = [data.xdata./(tmin(2)+data.xdata), <span class="keyword">...</span>
     -tmin(1).*data.xdata./(tmin(2)+data.xdata).^2];
tcov = inv(J'*J)*mse
</pre><pre class="codeoutput">
tcov =

   0.00024471      0.25011
      0.25011       320.84

</pre><p>We have to define three structures for inputs of the <tt>mcmcrun</tt> function: parameter, model, and options.  Parameter structure has a special form and it i