an> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">zeros</span><span class="p">((</span><span class="n">num_rows</span><span class="p">,</span> <span class="n">num_rows</span><span class="p">),</span> <span class="n">dtype</span><span class="o">=</span><span class="nb">complex</span><span class="p">)</span>
        <span class="n">right</span><span class="p">[</span><span class="mi">0</span><span class="p">:</span><span class="n">half_nrows</span><span class="p">,<