p>
        The implementation for D(&#966;, k) first performs argument reduction using the
        relations:
      </p>
<p>
        <span class="emphasis"><em>D(-&#966;, k) = -D(&#966;, k)</em></span>
      </p>
<p>
        and
      </p>
<p>
        <span class="emphasis"><em>D(n&#960;+&#966;, k) = 2nD(k) + D(&#966;, k)</em></span>
      </p>
<p>
        to move &#966; &#160; to the range [0, &#960;/2].
      </p>
<p>
        The functions are then implemented in terms of Carlson's integral R<sub>D</sub>
