sa">r</span><span class="sd">&quot;&quot;&quot;</span>
<span class="sd">    Compute the exchange potential operator.</span>

<span class="sd">    | Args;</span>
<span class="sd">    |     s: iDEA.system.System, System object.</span>
<span class="sd">    |     n: np.ndarray, Charge density of the system.</span>

<span class="sd">    | Returns:</span>
<span class="sd">    |     Vxc: np.ndarray, Exchange correlation potential energy operator.</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span clas