).</span><span class="n">eq</span><span class="p">.</span><span class="s1">&#39;GC&#39;</span><span class="p">)</span> <span class="k">then</span>

<span class="k">       if</span> <span class="p">(.</span><span class="nb">not</span><span class="p">.</span><span class="n">params</span><span class="p">%</span><span class="n">GC_coords</span><span class="p">)</span> <span class="k">then</span>

<span class="k">          call </span><span class="n">cart_to_cyl</span><span class="p">(</span><span class="n">vars