2>
    <div class="sourceCode"><pre class="sourceCode r"><code><span class="r-in"><span><span class="kw">if</span> <span class="op">(</span><span class="fu"><a href="has_sympy.html">has_sympy</a></span><span class="op">(</span><span class="op">)</span><span class="op">)</span> <span class="op">{</span></span></span>
<span class="r-in"><span>   <span class="va">x</span> <span class="op">&lt;-</span> <span class="fu"><a href="symbol.html">symbol</a></span><span class="op">(</span><span class="st">'x'</span><s