t is required. It can be specified overtly as the a keyword-value pair <code>method=&lt;inference&gt;</code> or implicitly as one of the following:</p>
<ul>
<li><code>sample</code> - obtain a sample from the posterior using HMC</li>
<li><code>optimize</code> - penalized maximum likelihood estimation</li>
<li><code>variational</code> - automatic variational inference</li>
<li><code>generate_quantities</code> - run model’s <code>generated quantities</code> block on existing sample to obtain new quantities o