nonzero coefficients</span>
<span class="sd">        Returns:</span>
<span class="sd">            vector of length n</span>
<span class="sd">        &#39;&#39;&#39;</span>
        <span class="n">AT</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">A</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
        <span class="n">