sp;&times;&nbsp;M&nbsp;&times;&nbsp;N
) arrays:
</p>
<div class="example">
<pre class="example">  complex(C_DOUBLE_COMPLEX), dimension(L,M,N) :: in, out
</pre></div>

<p>To plan a DFT for these arrays using <code>fftw_plan_dft_3d</code>, you could do:
</p>
<a name="index-fftw_005fplan_005fdft_005f3d-2"></a>
<div class="example">
<pre class="example">  plan = fftw_plan_dft_3d(N,M,L, in,out, FFTW_FORWARD,FFTW_ESTIMATE)
</pre></div>

<p>That is, from FFTW&rsquo;s perspective this is a N&nbsp;&times;&nbsp;M&nbs