in an array.<a name="DOCF2" href="#FOOT2"><sup>2</sup></a>  For
example, we say that a 2d transform has rank&nbsp;2, a 3d transform has
rank&nbsp;3, and so on.  You can plan transforms of arbitrary rank by
means of the following function:
</p>
<div class="example">
<pre class="example">fftw_plan fftw_plan_dft(int rank, const int *n,
                        fftw_complex *in, fftw_complex *out,
                        int sign, unsigned flags);
</pre></div>
<a name="index-fftw_005fplan_005fdft"></a>

<p>Here,