ass="mi">2</span>
                <span class="p">)</span>
                <span class="n">v_c</span><span class="p">[</span><span class="n">j</span><span class="p">]</span> <span class="o">=</span> <span class="n">energy</span> <span class="o">-</span> <span class="n">r_s</span> <span class="o">*</span> <span class="n">derivative</span>
        <span class="n">v_xc</span> <span class="o">=</span> <span class="n">v_x</span> <span class="o">+</span> <span class="n">v_c</span>
        <span class="k">if</span