mirror of
https://github.com/tildearrow/furnace.git
synced 2024-12-20 23:40:23 +00:00
187 lines
10 KiB
HTML
187 lines
10 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!-- This manual is for FFTW
|
|
(version 3.3.10, 10 December 2020).
|
|
|
|
Copyright (C) 2003 Matteo Frigo.
|
|
|
|
Copyright (C) 2003 Massachusetts Institute of Technology.
|
|
|
|
Permission is granted to make and distribute verbatim copies of this
|
|
manual provided the copyright notice and this permission notice are
|
|
preserved on all copies.
|
|
|
|
Permission is granted to copy and distribute modified versions of this
|
|
manual under the conditions for verbatim copying, provided that the
|
|
entire resulting derived work is distributed under the terms of a
|
|
permission notice identical to this one.
|
|
|
|
Permission is granted to copy and distribute translations of this manual
|
|
into another language, under the above conditions for modified versions,
|
|
except that this permission notice may be stated in a translation
|
|
approved by the Free Software Foundation. -->
|
|
<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<title>MPI Data Distribution Functions (FFTW 3.3.10)</title>
|
|
|
|
<meta name="description" content="MPI Data Distribution Functions (FFTW 3.3.10)">
|
|
<meta name="keywords" content="MPI Data Distribution Functions (FFTW 3.3.10)">
|
|
<meta name="resource-type" content="document">
|
|
<meta name="distribution" content="global">
|
|
<meta name="Generator" content="makeinfo">
|
|
<link href="index.html" rel="start" title="Top">
|
|
<link href="Concept-Index.html" rel="index" title="Concept Index">
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
|
<link href="FFTW-MPI-Reference.html" rel="up" title="FFTW MPI Reference">
|
|
<link href="MPI-Plan-Creation.html" rel="next" title="MPI Plan Creation">
|
|
<link href="Using-MPI-Plans.html" rel="prev" title="Using MPI Plans">
|
|
<style type="text/css">
|
|
<!--
|
|
a.summary-letter {text-decoration: none}
|
|
blockquote.indentedblock {margin-right: 0em}
|
|
div.display {margin-left: 3.2em}
|
|
div.example {margin-left: 3.2em}
|
|
div.lisp {margin-left: 3.2em}
|
|
kbd {font-style: oblique}
|
|
pre.display {font-family: inherit}
|
|
pre.format {font-family: inherit}
|
|
pre.menu-comment {font-family: serif}
|
|
pre.menu-preformatted {font-family: serif}
|
|
span.nolinebreak {white-space: nowrap}
|
|
span.roman {font-family: initial; font-weight: normal}
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
|
ul.no-bullet {list-style: none}
|
|
-->
|
|
</style>
|
|
|
|
|
|
</head>
|
|
|
|
<body lang="en">
|
|
<span id="MPI-Data-Distribution-Functions"></span><div class="header">
|
|
<p>
|
|
Next: <a href="MPI-Plan-Creation.html" accesskey="n" rel="next">MPI Plan Creation</a>, Previous: <a href="Using-MPI-Plans.html" accesskey="p" rel="prev">Using MPI Plans</a>, Up: <a href="FFTW-MPI-Reference.html" accesskey="u" rel="up">FFTW MPI Reference</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>
|
|
</div>
|
|
<hr>
|
|
<span id="MPI-Data-Distribution-Functions-1"></span><h4 class="subsection">6.12.4 MPI Data Distribution Functions</h4>
|
|
|
|
<span id="index-data-distribution-5"></span>
|
|
<p>As described above (see <a href="MPI-Data-Distribution.html">MPI Data Distribution</a>), in order to
|
|
allocate your arrays, <em>before</em> creating a plan, you must first
|
|
call one of the following routines to determine the required
|
|
allocation size and the portion of the array locally stored on a given
|
|
process. The <code>MPI_Comm</code> communicator passed here must be
|
|
equivalent to the communicator used below for plan creation.
|
|
</p>
|
|
<p>The basic interface for multidimensional transforms consists of the
|
|
functions:
|
|
</p>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005f2d-2"></span>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005f3d"></span>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize"></span>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005f2d_005ftransposed-1"></span>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005f3d_005ftransposed-1"></span>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005ftransposed"></span>
|
|
<div class="example">
|
|
<pre class="example">ptrdiff_t fftw_mpi_local_size_2d(ptrdiff_t n0, ptrdiff_t n1, MPI_Comm comm,
|
|
ptrdiff_t *local_n0, ptrdiff_t *local_0_start);
|
|
ptrdiff_t fftw_mpi_local_size_3d(ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t n2,
|
|
MPI_Comm comm,
|
|
ptrdiff_t *local_n0, ptrdiff_t *local_0_start);
|
|
ptrdiff_t fftw_mpi_local_size(int rnk, const ptrdiff_t *n, MPI_Comm comm,
|
|
ptrdiff_t *local_n0, ptrdiff_t *local_0_start);
|
|
|
|
ptrdiff_t fftw_mpi_local_size_2d_transposed(ptrdiff_t n0, ptrdiff_t n1, MPI_Comm comm,
|
|
ptrdiff_t *local_n0, ptrdiff_t *local_0_start,
|
|
ptrdiff_t *local_n1, ptrdiff_t *local_1_start);
|
|
ptrdiff_t fftw_mpi_local_size_3d_transposed(ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t n2,
|
|
MPI_Comm comm,
|
|
ptrdiff_t *local_n0, ptrdiff_t *local_0_start,
|
|
ptrdiff_t *local_n1, ptrdiff_t *local_1_start);
|
|
ptrdiff_t fftw_mpi_local_size_transposed(int rnk, const ptrdiff_t *n, MPI_Comm comm,
|
|
ptrdiff_t *local_n0, ptrdiff_t *local_0_start,
|
|
ptrdiff_t *local_n1, ptrdiff_t *local_1_start);
|
|
</pre></div>
|
|
|
|
<p>These functions return the number of elements to allocate (complex
|
|
numbers for DFT/r2c/c2r plans, real numbers for r2r plans), whereas
|
|
the <code>local_n0</code> and <code>local_0_start</code> return the portion
|
|
(<code>local_0_start</code> to <code>local_0_start + local_n0 - 1</code>) of the
|
|
first dimension of an n<sub>0</sub> × n<sub>1</sub> × n<sub>2</sub> × … × n<sub>d-1</sub>
|
|
array that is stored on the local
|
|
process. See <a href="Basic-and-advanced-distribution-interfaces.html">Basic and advanced distribution interfaces</a>. For
|
|
<code>FFTW_MPI_TRANSPOSED_OUT</code> plans, the ‘<samp>_transposed</samp>’ variants
|
|
are useful in order to also return the local portion of the first
|
|
dimension in the n<sub>1</sub> × n<sub>0</sub> × n<sub>2</sub> ×…× n<sub>d-1</sub>
|
|
transposed output.
|
|
See <a href="Transposed-distributions.html">Transposed distributions</a>.
|
|
The advanced interface for multidimensional transforms is:
|
|
</p>
|
|
<span id="index-advanced-interface-5"></span>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005fmany-1"></span>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005fmany_005ftransposed-1"></span>
|
|
<div class="example">
|
|
<pre class="example">ptrdiff_t fftw_mpi_local_size_many(int rnk, const ptrdiff_t *n, ptrdiff_t howmany,
|
|
ptrdiff_t block0, MPI_Comm comm,
|
|
ptrdiff_t *local_n0, ptrdiff_t *local_0_start);
|
|
ptrdiff_t fftw_mpi_local_size_many_transposed(int rnk, const ptrdiff_t *n, ptrdiff_t howmany,
|
|
ptrdiff_t block0, ptrdiff_t block1, MPI_Comm comm,
|
|
ptrdiff_t *local_n0, ptrdiff_t *local_0_start,
|
|
ptrdiff_t *local_n1, ptrdiff_t *local_1_start);
|
|
</pre></div>
|
|
|
|
<p>These differ from the basic interface in only two ways. First, they
|
|
allow you to specify block sizes <code>block0</code> and <code>block1</code> (the
|
|
latter for the transposed output); you can pass
|
|
<code>FFTW_MPI_DEFAULT_BLOCK</code> to use FFTW’s default block size as in
|
|
the basic interface. Second, you can pass a <code>howmany</code> parameter,
|
|
corresponding to the advanced planning interface below: this is for
|
|
transforms of contiguous <code>howmany</code>-tuples of numbers
|
|
(<code>howmany = 1</code> in the basic interface).
|
|
</p>
|
|
<p>The corresponding basic and advanced routines for one-dimensional
|
|
transforms (currently only complex DFTs) are:
|
|
</p>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005f1d-1"></span>
|
|
<span id="index-fftw_005fmpi_005flocal_005fsize_005fmany_005f1d"></span>
|
|
<div class="example">
|
|
<pre class="example">ptrdiff_t fftw_mpi_local_size_1d(
|
|
ptrdiff_t n0, MPI_Comm comm, int sign, unsigned flags,
|
|
ptrdiff_t *local_ni, ptrdiff_t *local_i_start,
|
|
ptrdiff_t *local_no, ptrdiff_t *local_o_start);
|
|
ptrdiff_t fftw_mpi_local_size_many_1d(
|
|
ptrdiff_t n0, ptrdiff_t howmany,
|
|
MPI_Comm comm, int sign, unsigned flags,
|
|
ptrdiff_t *local_ni, ptrdiff_t *local_i_start,
|
|
ptrdiff_t *local_no, ptrdiff_t *local_o_start);
|
|
</pre></div>
|
|
|
|
<span id="index-FFTW_005fMPI_005fSCRAMBLED_005fOUT-1"></span>
|
|
<span id="index-FFTW_005fMPI_005fSCRAMBLED_005fIN-1"></span>
|
|
<p>As above, the return value is the number of elements to allocate
|
|
(complex numbers, for complex DFTs). The <code>local_ni</code> and
|
|
<code>local_i_start</code> arguments return the portion
|
|
(<code>local_i_start</code> to <code>local_i_start + local_ni - 1</code>) of the
|
|
1d array that is stored on this process for the transform
|
|
<em>input</em>, and <code>local_no</code> and <code>local_o_start</code> are the
|
|
corresponding quantities for the input. The <code>sign</code>
|
|
(<code>FFTW_FORWARD</code> or <code>FFTW_BACKWARD</code>) and <code>flags</code> must
|
|
match the arguments passed when creating a plan. Although the inputs
|
|
and outputs have different data distributions in general, it is
|
|
guaranteed that the <em>output</em> data distribution of an
|
|
<code>FFTW_FORWARD</code> plan will match the <em>input</em> data distribution
|
|
of an <code>FFTW_BACKWARD</code> plan and vice versa; similarly for the
|
|
<code>FFTW_MPI_SCRAMBLED_OUT</code> and <code>FFTW_MPI_SCRAMBLED_IN</code> flags.
|
|
See <a href="One_002ddimensional-distributions.html">One-dimensional distributions</a>.
|
|
</p>
|
|
<hr>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="MPI-Plan-Creation.html" accesskey="n" rel="next">MPI Plan Creation</a>, Previous: <a href="Using-MPI-Plans.html" accesskey="p" rel="prev">Using MPI Plans</a>, Up: <a href="FFTW-MPI-Reference.html" accesskey="u" rel="up">FFTW MPI Reference</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>
|
|
</div>
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|