)</span>
                <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">n_x</span><span class="p">):</span>
                    <span class="n">x_i</span> <span class="o">=</span> <span class="n">x</span><span class="p">[</span><span class="n">i</span><span class="p">]</span>
                    <span class="n">C_ii</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span cla