ess_fraction:</span>
   <span class="identifier">negative_binomial_distribution</span><span class="special">(</span><span class="identifier">RealType</span> <span class="identifier">r</span><span class="special">,</span> <span class="identifier">RealType</span> <span class="identifier">p</span><span class="special">);</span>

   <span class="comment">// Parameter accessors:</span>
   <span class="identifier">RealType</span> <span class="identifier">success_fraction</span><span class="special">()</span> <spa