is function is deprecated and should be replaced with
<code>lmultiply</code>. Return the product of x and the natural logarithm of y.
<span class="math display">\[ \mathrm{multiply\_log}(x,y) = \begin{cases} 0 &amp; \text{if } x = y =
0 \\ x \log y &amp; \text{if } x, y \neq 0 \\ \text{NaN} &amp;
\text{otherwise} \end{cases} \]</span></p>
<!-- real; lmultiply; (real x, real y); -->
<p></p>
<p><code>real</code> <strong><code>lmultiply</code></strong><code>(real x, real y)</code><br>
Return the product of x a