"comment">// T elliptic_root_1_deriv  Newton-Raphson</span>
</pre>
<p>
        The number of iterations required for <code class="computeroutput"><span class="keyword">double</span></code>
        precision is now usually around 4 - so we've slightly more than halved the
        number of iterations, but made the functor twice as expensive to call!
      </p>
<p>
        Interestingly though, the second derivative requires no more expensive elliptic
        integral calls than the first does, in other words