n level3 unnumbered">
<h3>Constrained Real</h3>
<p>Real variables may be bounded using the same syntax as integers. In
theory (that is, with arbitrary-precision arithmetic), the bounds on
real values would be exclusive. Unfortunately, finite-precision
arithmetic rounding errors will often lead to values on the
boundaries, so they are allowed in Stan.</p>
<p>The variable <code>sigma</code> may be declared to be non-negative as follows.</p>
<pre class="stan"><code>real&lt;lower=0&gt; sigma;</code></pre>
<p>Th