e>log_sum_exp</code></strong><code>(real x, real y)</code><br>
Return the natural logarithm of the sum of the natural exponentiation
of x and the natural exponentiation of y. <span class="math display">\[
\mathrm{log\_sum\_exp}(x,y) = \log(\exp(x)+\exp(y)) \]</span></p>
<!-- R; log_inv_logit; (T x); -->
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<p><code>R</code> <strong><code>log_inv_logit</code></strong><code>(T x)</code><br>
natural logarithm of the inverse logit function of x</p>
<!-- R; log1m_inv_logit; (T x); -->
<p></p>
<p><code>R</co