Mercurial > hg > sv-dependency-builds
diff src/fftw-3.3.8/doc/html/Other-Multi_002ddimensional-Real_002ddata-MPI-Transforms.html @ 82:d0c2a83c1364
Add FFTW 3.3.8 source, and a Linux build
| author | Chris Cannam |
|---|---|
| date | Tue, 19 Nov 2019 14:52:55 +0000 |
| parents | |
| children |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/fftw-3.3.8/doc/html/Other-Multi_002ddimensional-Real_002ddata-MPI-Transforms.html Tue Nov 19 14:52:55 2019 +0000 @@ -0,0 +1,132 @@ +<!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 3.3.8, 24 May 2018). + +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 6.3, http://www.gnu.org/software/texinfo/ --> +<head> +<title>FFTW 3.3.8: Other Multi-dimensional Real-data MPI Transforms</title> + +<meta name="description" content="FFTW 3.3.8: Other Multi-dimensional Real-data MPI Transforms"> +<meta name="keywords" content="FFTW 3.3.8: Other Multi-dimensional Real-data MPI Transforms"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Distributed_002dmemory-FFTW-with-MPI.html#Distributed_002dmemory-FFTW-with-MPI" rel="up" title="Distributed-memory FFTW with MPI"> +<link href="FFTW-MPI-Transposes.html#FFTW-MPI-Transposes" rel="next" title="FFTW MPI Transposes"> +<link href="Multi_002ddimensional-MPI-DFTs-of-Real-Data.html#Multi_002ddimensional-MPI-DFTs-of-Real-Data" rel="prev" title="Multi-dimensional MPI DFTs of Real Data"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.indentedblock {margin-right: 0em} +blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smalllisp {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} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +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"> +<a name="Other-Multi_002ddimensional-Real_002ddata-MPI-Transforms"></a> +<div class="header"> +<p> +Next: <a href="FFTW-MPI-Transposes.html#FFTW-MPI-Transposes" accesskey="n" rel="next">FFTW MPI Transposes</a>, Previous: <a href="Multi_002ddimensional-MPI-DFTs-of-Real-Data.html#Multi_002ddimensional-MPI-DFTs-of-Real-Data" accesskey="p" rel="prev">Multi-dimensional MPI DFTs of Real Data</a>, Up: <a href="Distributed_002dmemory-FFTW-with-MPI.html#Distributed_002dmemory-FFTW-with-MPI" accesskey="u" rel="up">Distributed-memory FFTW with MPI</a> [<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> +</div> +<hr> +<a name="Other-multi_002ddimensional-Real_002dData-MPI-Transforms"></a> +<h3 class="section">6.6 Other multi-dimensional Real-Data MPI Transforms</h3> + +<a name="index-r2r-3"></a> +<p>FFTW’s MPI interface also supports multi-dimensional ‘<samp>r2r</samp>’ +transforms of all kinds supported by the serial interface +(e.g. discrete cosine and sine transforms, discrete Hartley +transforms, etc.). Only multi-dimensional ‘<samp>r2r</samp>’ transforms, not +one-dimensional transforms, are currently parallelized. +</p> +<a name="index-fftw_005fr2r_005fkind-1"></a> +<p>These are used much like the multidimensional complex DFTs discussed +above, except that the data is real rather than complex, and one needs +to pass an r2r transform kind (<code>fftw_r2r_kind</code>) for each +dimension as in the serial FFTW (see <a href="More-DFTs-of-Real-Data.html#More-DFTs-of-Real-Data">More DFTs of Real Data</a>). +</p> +<p>For example, one might perform a two-dimensional L × M + that is +an REDFT10 (DCT-II) in the first dimension and an RODFT10 (DST-II) in +the second dimension with code like: +</p> +<div class="example"> +<pre class="example"> const ptrdiff_t L = ..., M = ...; + fftw_plan plan; + double *data; + ptrdiff_t alloc_local, local_n0, local_0_start, i, j; + + /* <span class="roman">get local data size and allocate</span> */ + alloc_local = fftw_mpi_local_size_2d(L, M, MPI_COMM_WORLD, + &local_n0, &local_0_start); + data = fftw_alloc_real(alloc_local); + + /* <span class="roman">create plan for in-place REDFT10 x RODFT10</span> */ + plan = fftw_mpi_plan_r2r_2d(L, M, data, data, MPI_COMM_WORLD, + FFTW_REDFT10, FFTW_RODFT10, FFTW_MEASURE); + + /* <span class="roman">initialize data to some function</span> my_function(x,y) */ + for (i = 0; i < local_n0; ++i) for (j = 0; j < M; ++j) + data[i*M + j] = my_function(local_0_start + i, j); + + /* <span class="roman">compute transforms, in-place, as many times as desired</span> */ + fftw_execute(plan); + + fftw_destroy_plan(plan); +</pre></div> + +<a name="index-fftw_005falloc_005freal-3"></a> +<p>Notice that we use the same ‘<samp>local_size</samp>’ functions as we did for +complex data, only now we interpret the sizes in terms of real rather +than complex values, and correspondingly use <code>fftw_alloc_real</code>. +</p> + + + +</body> +</html>