an><span class="o">.</span><span class="n">real</span><span class="p">(</span><span class="n">vec</span><span class="p">)</span>
                <span class="n">s_vec</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">imag</span><span class="p">(</span><span class="n">vec</span><span class="p">)</span>
                <span class="n">central_mats</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arctan2</span><span 