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cannam@127: <title>FFTW 3.3.5: Advanced distributed-transpose interface</title>
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cannam@127: <a name="Advanced-distributed_002dtranspose-interface-1"></a>
cannam@127: <h4 class="subsection">6.7.2 Advanced distributed-transpose interface</h4>
cannam@127:
cannam@127: <p>The above routines are for a transpose of a matrix of numbers (of type
cannam@127: <code>double</code>), using FFTW’s default block sizes. More generally, one
cannam@127: can perform transposes of <em>tuples</em> of numbers, with
cannam@127: user-specified block sizes for the input and output:
cannam@127: </p>
cannam@127: <div class="example">
cannam@127: <pre class="example">fftw_plan fftw_mpi_plan_many_transpose
cannam@127: (ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t howmany,
cannam@127: ptrdiff_t block0, ptrdiff_t block1,
cannam@127: double *in, double *out, MPI_Comm comm, unsigned flags);
cannam@127: </pre></div>
cannam@127: <a name="index-fftw_005fmpi_005fplan_005fmany_005ftranspose"></a>
cannam@127:
cannam@127: <p>In this case, one is transposing an <code>n0</code> by <code>n1</code> matrix of
cannam@127: <code>howmany</code>-tuples (e.g. <code>howmany = 2</code> for complex numbers).
cannam@127: The input is distributed along the <code>n0</code> dimension with block size
cannam@127: <code>block0</code>, and the <code>n1</code> by <code>n0</code> output is distributed
cannam@127: along the <code>n1</code> dimension with block size <code>block1</code>. If
cannam@127: <code>FFTW_MPI_DEFAULT_BLOCK</code> (0) is passed for a block size then FFTW
cannam@127: uses its default block size. To get the local size of the data on
cannam@127: each process, you should then call <code>fftw_mpi_local_size_many_transposed</code>.
cannam@127: <a name="index-FFTW_005fMPI_005fDEFAULT_005fBLOCK-1"></a>
cannam@127: <a name="index-fftw_005fmpi_005flocal_005fsize_005fmany_005ftransposed"></a>
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