n class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">abs</span><span class="p">(</span><span class="n">yf</span><span class="p">[</span><span class="mi">0</span><span class="p">:</span><span class="n">N</span><span class="o">//</span><span class="mi">2</span><span class="p">]))</span>
    <span class="c1"># removes first term (tends to be infinity or overly large)</span>
    <span class="n">yf</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><s