ndarray - forward coefficient.</span>
<span class="sd">        &quot;&quot;&quot;</span>

        <span class="k">if</span> <span class="ow">not</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">d</span><span class="p">,</span> <span class="n">numpy</span><span class="o">.</span><span class="n">ndarray</span><span class="p">):</span>
            <span class="n">d</span> <span class="o">=</span> <span class="n">numpy</span><span class="o">.</span><span class="n">array</span><sp