e>, <code>"cubic"</code>, <code>"pentaspherical"</code>, <code>"wave"</code>,
<code>"jbessel"</code>, <code>"gravity"</code>, <code>"rquad"</code>, <code>"magnetic"</code>, and
<code>"none"</code>.</p></dd>


<dt>rotate</dt>
<dd><p>Anisotropy rotation parameter (from 0 to \(\pi\) radians) for
the euclidean portion of the covariance. A value of 0 (the default) implies no rotation.</p></dd>


<dt>scale</dt>
<dd><p>Anisotropy scale parameter (from 0 to 1) for
the euclidean portion of the covariance. A value of