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Chris@42: <a name="Advanced-distributed_002dtranspose-interface-1"></a>
Chris@42: <h4 class="subsection">6.7.2 Advanced distributed-transpose interface</h4>
Chris@42:
Chris@42: <p>The above routines are for a transpose of a matrix of numbers (of type
Chris@42: <code>double</code>), using FFTW’s default block sizes. More generally, one
Chris@42: can perform transposes of <em>tuples</em> of numbers, with
Chris@42: user-specified block sizes for the input and output:
Chris@42: </p>
Chris@42: <div class="example">
Chris@42: <pre class="example">fftw_plan fftw_mpi_plan_many_transpose
Chris@42: (ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t howmany,
Chris@42: ptrdiff_t block0, ptrdiff_t block1,
Chris@42: double *in, double *out, MPI_Comm comm, unsigned flags);
Chris@42: </pre></div>
Chris@42: <a name="index-fftw_005fmpi_005fplan_005fmany_005ftranspose"></a>
Chris@42:
Chris@42: <p>In this case, one is transposing an <code>n0</code> by <code>n1</code> matrix of
Chris@42: <code>howmany</code>-tuples (e.g. <code>howmany = 2</code> for complex numbers).
Chris@42: The input is distributed along the <code>n0</code> dimension with block size
Chris@42: <code>block0</code>, and the <code>n1</code> by <code>n0</code> output is distributed
Chris@42: along the <code>n1</code> dimension with block size <code>block1</code>. If
Chris@42: <code>FFTW_MPI_DEFAULT_BLOCK</code> (0) is passed for a block size then FFTW
Chris@42: uses its default block size. To get the local size of the data on
Chris@42: each process, you should then call <code>fftw_mpi_local_size_many_transposed</code>.
Chris@42: <a name="index-FFTW_005fMPI_005fDEFAULT_005fBLOCK-1"></a>
Chris@42: <a name="index-fftw_005fmpi_005flocal_005fsize_005fmany_005ftransposed"></a>
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