 introduce conditional behavior functionally and
are primarily provided for compatibility with BUGS and JAGS.</p>
<!-- real; step; (real x); -->
<p></p>
<p><code>real</code> <strong><code>step</code></strong><code>(real x)</code><br>
Return 1 if x is positive and 0 otherwise. <span class="math display">\[ \text{step}(x) =
\begin{cases} 0 &amp; \text{if } x &lt; 0 \\ 1 &amp; \text{otherwise} \end{cases}
\]</span> <em><strong>Warning:</strong></em> <code>int_step(0)</code> and <code>int_step(NaN)</code> retur