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			98 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
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<!-- This manual is for FFTW
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(version 3.3.10, 10 December 2020).
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Copyright (C) 2003 Matteo Frigo.
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Copyright (C) 2003 Massachusetts Institute of Technology.
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Permission is granted to make and distribute verbatim copies of this
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<title>Advanced distributed-transpose interface (FFTW 3.3.10)</title>
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<span id="Advanced-distributed_002dtranspose-interface"></span><div class="header">
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Next: <a href="An-improved-replacement-for-MPI_005fAlltoall.html" accesskey="n" rel="next">An improved replacement for MPI_Alltoall</a>, Previous: <a href="Basic-distributed_002dtranspose-interface.html" accesskey="p" rel="prev">Basic distributed-transpose interface</a>, Up: <a href="FFTW-MPI-Transposes.html" accesskey="u" rel="up">FFTW MPI Transposes</a>   [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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<span id="Advanced-distributed_002dtranspose-interface-1"></span><h4 class="subsection">6.7.2 Advanced distributed-transpose interface</h4>
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<p>The above routines are for a transpose of a matrix of numbers (of type
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<code>double</code>), using FFTW’s default block sizes.  More generally, one
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can perform transposes of <em>tuples</em> of numbers, with
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user-specified block sizes for the input and output:
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</p>
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<div class="example">
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<pre class="example">fftw_plan fftw_mpi_plan_many_transpose
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                (ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t howmany,
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                 ptrdiff_t block0, ptrdiff_t block1,
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                 double *in, double *out, MPI_Comm comm, unsigned flags);
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</pre></div>
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<span id="index-fftw_005fmpi_005fplan_005fmany_005ftranspose"></span>
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<p>In this case, one is transposing an <code>n0</code> by <code>n1</code> matrix of
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<code>howmany</code>-tuples (e.g. <code>howmany = 2</code> for complex numbers).
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The input is distributed along the <code>n0</code> dimension with block size
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<code>block0</code>, and the <code>n1</code> by <code>n0</code> output is distributed
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along the <code>n1</code> dimension with block size <code>block1</code>.  If
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<code>FFTW_MPI_DEFAULT_BLOCK</code> (0) is passed for a block size then FFTW
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uses its default block size.  To get the local size of the data on
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each process, you should then call <code>fftw_mpi_local_size_many_transposed</code>.
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<span id="index-FFTW_005fMPI_005fDEFAULT_005fBLOCK-1"></span>
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<span id="index-fftw_005fmpi_005flocal_005fsize_005fmany_005ftransposed"></span>
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