Mercurial > hg > sv-dependency-builds

annotate src/fftw-3.3.8/doc/html/MPI-Data-Distribution-Functions.html @ 167:bd3cc4d1df30

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Add FFTW 3.3.8 source, and a Linux build
author Chris Cannam <cannam@all-day-breakfast.com>
date Tue, 19 Nov 2019 14:52:55 +0000
parents
children
rev   line source
cannam@167 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
cannam@167 2 <html>
cannam@167 3 <!-- This manual is for FFTW
cannam@167 4 (version 3.3.8, 24 May 2018).
cannam@167 5
cannam@167 6 Copyright (C) 2003 Matteo Frigo.
cannam@167 7
cannam@167 8 Copyright (C) 2003 Massachusetts Institute of Technology.
cannam@167 9
cannam@167 10 Permission is granted to make and distribute verbatim copies of this
cannam@167 11 manual provided the copyright notice and this permission notice are
cannam@167 12 preserved on all copies.
cannam@167 13
cannam@167 14 Permission is granted to copy and distribute modified versions of this
cannam@167 15 manual under the conditions for verbatim copying, provided that the
cannam@167 16 entire resulting derived work is distributed under the terms of a
cannam@167 17 permission notice identical to this one.
cannam@167 18
cannam@167 19 Permission is granted to copy and distribute translations of this manual
cannam@167 20 into another language, under the above conditions for modified versions,
cannam@167 21 except that this permission notice may be stated in a translation
cannam@167 22 approved by the Free Software Foundation. -->
cannam@167 23 <!-- Created by GNU Texinfo 6.3, http://www.gnu.org/software/texinfo/ -->
cannam@167 24 <head>
cannam@167 25 <title>FFTW 3.3.8: MPI Data Distribution Functions</title>
cannam@167 26
cannam@167 27 <meta name="description" content="FFTW 3.3.8: MPI Data Distribution Functions">
cannam@167 28 <meta name="keywords" content="FFTW 3.3.8: MPI Data Distribution Functions">
cannam@167 29 <meta name="resource-type" content="document">
cannam@167 30 <meta name="distribution" content="global">
cannam@167 31 <meta name="Generator" content="makeinfo">
cannam@167 32 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
cannam@167 33 <link href="index.html#Top" rel="start" title="Top">
cannam@167 34 <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
cannam@167 35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
cannam@167 36 <link href="FFTW-MPI-Reference.html#FFTW-MPI-Reference" rel="up" title="FFTW MPI Reference">
cannam@167 37 <link href="MPI-Plan-Creation.html#MPI-Plan-Creation" rel="next" title="MPI Plan Creation">
cannam@167 38 <link href="Using-MPI-Plans.html#Using-MPI-Plans" rel="prev" title="Using MPI Plans">
cannam@167 39 <style type="text/css">
cannam@167 40 <!--
cannam@167 41 a.summary-letter {text-decoration: none}
cannam@167 42 blockquote.indentedblock {margin-right: 0em}
cannam@167 43 blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
cannam@167 44 blockquote.smallquotation {font-size: smaller}
cannam@167 45 div.display {margin-left: 3.2em}
cannam@167 46 div.example {margin-left: 3.2em}
cannam@167 47 div.lisp {margin-left: 3.2em}
cannam@167 48 div.smalldisplay {margin-left: 3.2em}
cannam@167 49 div.smallexample {margin-left: 3.2em}
cannam@167 50 div.smalllisp {margin-left: 3.2em}
cannam@167 51 kbd {font-style: oblique}
cannam@167 52 pre.display {font-family: inherit}
cannam@167 53 pre.format {font-family: inherit}
cannam@167 54 pre.menu-comment {font-family: serif}
cannam@167 55 pre.menu-preformatted {font-family: serif}
cannam@167 56 pre.smalldisplay {font-family: inherit; font-size: smaller}
cannam@167 57 pre.smallexample {font-size: smaller}
cannam@167 58 pre.smallformat {font-family: inherit; font-size: smaller}
cannam@167 59 pre.smalllisp {font-size: smaller}
cannam@167 60 span.nolinebreak {white-space: nowrap}
cannam@167 61 span.roman {font-family: initial; font-weight: normal}
cannam@167 62 span.sansserif {font-family: sans-serif; font-weight: normal}
cannam@167 63 ul.no-bullet {list-style: none}
cannam@167 64 -->
cannam@167 65 </style>
cannam@167 66
cannam@167 67
cannam@167 68 </head>
cannam@167 69
cannam@167 70 <body lang="en">
cannam@167 71 <a name="MPI-Data-Distribution-Functions"></a>
cannam@167 72 <div class="header">
cannam@167 73 <p>
cannam@167 74 Next: <a href="MPI-Plan-Creation.html#MPI-Plan-Creation" accesskey="n" rel="next">MPI Plan Creation</a>, Previous: <a href="Using-MPI-Plans.html#Using-MPI-Plans" accesskey="p" rel="prev">Using MPI Plans</a>, Up: <a href="FFTW-MPI-Reference.html#FFTW-MPI-Reference" accesskey="u" rel="up">FFTW MPI Reference</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
cannam@167 75 </div>
cannam@167 76 <hr>
cannam@167 77 <a name="MPI-Data-Distribution-Functions-1"></a>
cannam@167 78 <h4 class="subsection">6.12.4 MPI Data Distribution Functions</h4>
cannam@167 79
cannam@167 80 <a name="index-data-distribution-5"></a>
cannam@167 81 <p>As described above (see <a href="MPI-Data-Distribution.html#MPI-Data-Distribution">MPI Data Distribution</a>), in order to
cannam@167 82 allocate your arrays, <em>before</em> creating a plan, you must first
cannam@167 83 call one of the following routines to determine the required
cannam@167 84 allocation size and the portion of the array locally stored on a given
cannam@167 85 process. The <code>MPI_Comm</code> communicator passed here must be
cannam@167 86 equivalent to the communicator used below for plan creation.
cannam@167 87 </p>
cannam@167 88 <p>The basic interface for multidimensional transforms consists of the
cannam@167 89 functions:
cannam@167 90 </p>
cannam@167 91 <a name="index-fftw_005fmpi_005flocal_005fsize_005f2d-2"></a>
cannam@167 92 <a name="index-fftw_005fmpi_005flocal_005fsize_005f3d"></a>
cannam@167 93 <a name="index-fftw_005fmpi_005flocal_005fsize"></a>
cannam@167 94 <a name="index-fftw_005fmpi_005flocal_005fsize_005f2d_005ftransposed-1"></a>
cannam@167 95 <a name="index-fftw_005fmpi_005flocal_005fsize_005f3d_005ftransposed-1"></a>
cannam@167 96 <a name="index-fftw_005fmpi_005flocal_005fsize_005ftransposed"></a>
cannam@167 97 <div class="example">
cannam@167 98 <pre class="example">ptrdiff_t fftw_mpi_local_size_2d(ptrdiff_t n0, ptrdiff_t n1, MPI_Comm comm,
cannam@167 99 ptrdiff_t *local_n0, ptrdiff_t *local_0_start);
cannam@167 100 ptrdiff_t fftw_mpi_local_size_3d(ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t n2,
cannam@167 101 MPI_Comm comm,
cannam@167 102 ptrdiff_t *local_n0, ptrdiff_t *local_0_start);
cannam@167 103 ptrdiff_t fftw_mpi_local_size(int rnk, const ptrdiff_t *n, MPI_Comm comm,
cannam@167 104 ptrdiff_t *local_n0, ptrdiff_t *local_0_start);
cannam@167 105
cannam@167 106 ptrdiff_t fftw_mpi_local_size_2d_transposed(ptrdiff_t n0, ptrdiff_t n1, MPI_Comm comm,
cannam@167 107 ptrdiff_t *local_n0, ptrdiff_t *local_0_start,
cannam@167 108 ptrdiff_t *local_n1, ptrdiff_t *local_1_start);
cannam@167 109 ptrdiff_t fftw_mpi_local_size_3d_transposed(ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t n2,
cannam@167 110 MPI_Comm comm,
cannam@167 111 ptrdiff_t *local_n0, ptrdiff_t *local_0_start,
cannam@167 112 ptrdiff_t *local_n1, ptrdiff_t *local_1_start);
cannam@167 113 ptrdiff_t fftw_mpi_local_size_transposed(int rnk, const ptrdiff_t *n, MPI_Comm comm,
cannam@167 114 ptrdiff_t *local_n0, ptrdiff_t *local_0_start,
cannam@167 115 ptrdiff_t *local_n1, ptrdiff_t *local_1_start);
cannam@167 116 </pre></div>
cannam@167 117
cannam@167 118 <p>These functions return the number of elements to allocate (complex
cannam@167 119 numbers for DFT/r2c/c2r plans, real numbers for r2r plans), whereas
cannam@167 120 the <code>local_n0</code> and <code>local_0_start</code> return the portion
cannam@167 121 (<code>local_0_start</code> to <code>local_0_start + local_n0 - 1</code>) of the
cannam@167 122 first dimension of an n<sub>0</sub>&nbsp;&times;&nbsp;n<sub>1</sub>&nbsp;&times;&nbsp;n<sub>2</sub>&nbsp;&times;&nbsp;&hellip;&nbsp;&times;&nbsp;n<sub>d-1</sub>
cannam@167 123 array that is stored on the local
cannam@167 124 process. See <a href="Basic-and-advanced-distribution-interfaces.html#Basic-and-advanced-distribution-interfaces">Basic and advanced distribution interfaces</a>. For
cannam@167 125 <code>FFTW_MPI_TRANSPOSED_OUT</code> plans, the &lsquo;<samp>_transposed</samp>&rsquo; variants
cannam@167 126 are useful in order to also return the local portion of the first
cannam@167 127 dimension in the n<sub>1</sub>&nbsp;&times;&nbsp;n<sub>0</sub>&nbsp;&times;&nbsp;n<sub>2</sub>&nbsp;&times;&hellip;&times;&nbsp;n<sub>d-1</sub>
cannam@167 128 transposed output.
cannam@167 129 See <a href="Transposed-distributions.html#Transposed-distributions">Transposed distributions</a>.
cannam@167 130 The advanced interface for multidimensional transforms is:
cannam@167 131 </p>
cannam@167 132 <a name="index-advanced-interface-5"></a>
cannam@167 133 <a name="index-fftw_005fmpi_005flocal_005fsize_005fmany-1"></a>
cannam@167 134 <a name="index-fftw_005fmpi_005flocal_005fsize_005fmany_005ftransposed-1"></a>
cannam@167 135 <div class="example">
cannam@167 136 <pre class="example">ptrdiff_t fftw_mpi_local_size_many(int rnk, const ptrdiff_t *n, ptrdiff_t howmany,
cannam@167 137 ptrdiff_t block0, MPI_Comm comm,
cannam@167 138 ptrdiff_t *local_n0, ptrdiff_t *local_0_start);
cannam@167 139 ptrdiff_t fftw_mpi_local_size_many_transposed(int rnk, const ptrdiff_t *n, ptrdiff_t howmany,
cannam@167 140 ptrdiff_t block0, ptrdiff_t block1, MPI_Comm comm,
cannam@167 141 ptrdiff_t *local_n0, ptrdiff_t *local_0_start,
cannam@167 142 ptrdiff_t *local_n1, ptrdiff_t *local_1_start);
cannam@167 143 </pre></div>
cannam@167 144
cannam@167 145 <p>These differ from the basic interface in only two ways. First, they
cannam@167 146 allow you to specify block sizes <code>block0</code> and <code>block1</code> (the
cannam@167 147 latter for the transposed output); you can pass
cannam@167 148 <code>FFTW_MPI_DEFAULT_BLOCK</code> to use FFTW&rsquo;s default block size as in
cannam@167 149 the basic interface. Second, you can pass a <code>howmany</code> parameter,
cannam@167 150 corresponding to the advanced planning interface below: this is for
cannam@167 151 transforms of contiguous <code>howmany</code>-tuples of numbers
cannam@167 152 (<code>howmany = 1</code> in the basic interface).
cannam@167 153 </p>
cannam@167 154 <p>The corresponding basic and advanced routines for one-dimensional
cannam@167 155 transforms (currently only complex DFTs) are:
cannam@167 156 </p>
cannam@167 157 <a name="index-fftw_005fmpi_005flocal_005fsize_005f1d-1"></a>
cannam@167 158 <a name="index-fftw_005fmpi_005flocal_005fsize_005fmany_005f1d"></a>
cannam@167 159 <div class="example">
cannam@167 160 <pre class="example">ptrdiff_t fftw_mpi_local_size_1d(
cannam@167 161 ptrdiff_t n0, MPI_Comm comm, int sign, unsigned flags,
cannam@167 162 ptrdiff_t *local_ni, ptrdiff_t *local_i_start,
cannam@167 163 ptrdiff_t *local_no, ptrdiff_t *local_o_start);
cannam@167 164 ptrdiff_t fftw_mpi_local_size_many_1d(
cannam@167 165 ptrdiff_t n0, ptrdiff_t howmany,
cannam@167 166 MPI_Comm comm, int sign, unsigned flags,
cannam@167 167 ptrdiff_t *local_ni, ptrdiff_t *local_i_start,
cannam@167 168 ptrdiff_t *local_no, ptrdiff_t *local_o_start);
cannam@167 169 </pre></div>
cannam@167 170
cannam@167 171 <a name="index-FFTW_005fMPI_005fSCRAMBLED_005fOUT-1"></a>
cannam@167 172 <a name="index-FFTW_005fMPI_005fSCRAMBLED_005fIN-1"></a>
cannam@167 173 <p>As above, the return value is the number of elements to allocate
cannam@167 174 (complex numbers, for complex DFTs). The <code>local_ni</code> and
cannam@167 175 <code>local_i_start</code> arguments return the portion
cannam@167 176 (<code>local_i_start</code> to <code>local_i_start + local_ni - 1</code>) of the
cannam@167 177 1d array that is stored on this process for the transform
cannam@167 178 <em>input</em>, and <code>local_no</code> and <code>local_o_start</code> are the
cannam@167 179 corresponding quantities for the input. The <code>sign</code>
cannam@167 180 (<code>FFTW_FORWARD</code> or <code>FFTW_BACKWARD</code>) and <code>flags</code> must
cannam@167 181 match the arguments passed when creating a plan. Although the inputs
cannam@167 182 and outputs have different data distributions in general, it is
cannam@167 183 guaranteed that the <em>output</em> data distribution of an
cannam@167 184 <code>FFTW_FORWARD</code> plan will match the <em>input</em> data distribution
cannam@167 185 of an <code>FFTW_BACKWARD</code> plan and vice versa; similarly for the
cannam@167 186 <code>FFTW_MPI_SCRAMBLED_OUT</code> and <code>FFTW_MPI_SCRAMBLED_IN</code> flags.
cannam@167 187 See <a href="One_002ddimensional-distributions.html#One_002ddimensional-distributions">One-dimensional distributions</a>.
cannam@167 188 </p>
cannam@167 189 <hr>
cannam@167 190 <div class="header">
cannam@167 191 <p>
cannam@167 192 Next: <a href="MPI-Plan-Creation.html#MPI-Plan-Creation" accesskey="n" rel="next">MPI Plan Creation</a>, Previous: <a href="Using-MPI-Plans.html#Using-MPI-Plans" accesskey="p" rel="prev">Using MPI Plans</a>, Up: <a href="FFTW-MPI-Reference.html#FFTW-MPI-Reference" accesskey="u" rel="up">FFTW MPI Reference</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
cannam@167 193 </div>
cannam@167 194
cannam@167 195
cannam@167 196
cannam@167 197 </body>
cannam@167 198 </html>