an><span class="p">)</span>
        <span class="k">else</span><span class="p">:</span>
            <span class="n">c</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">empty</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
        <span class="n">d</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">init_derivatives_array</span><span class="p">(</span><span class="n">n_centers</span>