tributed
across the <code>n1</code> dimension, we would create a plan by calling the
following function:

<pre class="example">     fftw_plan fftw_mpi_plan_transpose(ptrdiff_t n0, ptrdiff_t n1,
                                       double *in, double *out,
                                       MPI_Comm comm, unsigned flags);
</pre>
   <p><a name="index-fftw_005fmpi_005fplan_005ftranspose-400"></a>
The input and output arrays (<code>in</code> and <code>out</code>) can be the
same.  The transpose is actuall