noisy data.</span>
<span class="keyword">auto</span> <span class="identifier">lanczos</span> <span class="special">=</span> <span class="identifier">lanczos_derivative</span><span class="special">(</span><span class="identifier">spacing</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;</span> <span class="identifier">dv1dt<