target += sum(alpha_raw);  // log Jacobian
  ...</code></pre>
<p>The adjustment in the the log Jacobian determinant of the transform
mapping <span class="math inline">\(\alpha_{\mathrm{raw}}\)</span> to
<span class="math inline">\(\alpha = L + \exp(\alpha_{\mathrm{raw}})\)</span>. The details are simple in
this case because the Jacobian is diagonal; see the reference manual
chapter on constrained parameter transforms for full details. Here
<span class="math inline">\(L\)</span> can even be a vector containi