314 lines
		
	
	
		
			18 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
		
		
			
		
	
	
			314 lines
		
	
	
		
			18 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 Plan Creation (FFTW 3.3.10)</title> | ||
|  | 
 | ||
|  | <meta name="description" content="MPI Plan Creation (FFTW 3.3.10)"> | ||
|  | <meta name="keywords" content="MPI Plan Creation (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-Wisdom-Communication.html" rel="next" title="MPI Wisdom Communication"> | ||
|  | <link href="MPI-Data-Distribution-Functions.html" rel="prev" title="MPI Data Distribution Functions"> | ||
|  | <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-Plan-Creation"></span><div class="header"> | ||
|  | <p> | ||
|  | Next: <a href="MPI-Wisdom-Communication.html" accesskey="n" rel="next">MPI Wisdom Communication</a>, Previous: <a href="MPI-Data-Distribution-Functions.html" accesskey="p" rel="prev">MPI Data Distribution Functions</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-Plan-Creation-1"></span><h4 class="subsection">6.12.5 MPI Plan Creation</h4> | ||
|  | 
 | ||
|  | <span id="Complex_002ddata-MPI-DFTs"></span><h4 class="subsubheading">Complex-data MPI DFTs</h4> | ||
|  | 
 | ||
|  | <p>Plans for complex-data DFTs (see <a href="2d-MPI-example.html">2d MPI example</a>) are created by: | ||
|  | </p> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005f1d"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005f2d-1"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005f3d"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fmany_005fdft"></span> | ||
|  | <div class="example"> | ||
|  | <pre class="example">fftw_plan fftw_mpi_plan_dft_1d(ptrdiff_t n0, fftw_complex *in, fftw_complex *out, | ||
|  |                                MPI_Comm comm, int sign, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_2d(ptrdiff_t n0, ptrdiff_t n1, | ||
|  |                                fftw_complex *in, fftw_complex *out, | ||
|  |                                MPI_Comm comm, int sign, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_3d(ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t n2, | ||
|  |                                fftw_complex *in, fftw_complex *out, | ||
|  |                                MPI_Comm comm, int sign, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft(int rnk, const ptrdiff_t *n,  | ||
|  |                             fftw_complex *in, fftw_complex *out, | ||
|  |                             MPI_Comm comm, int sign, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_many_dft(int rnk, const ptrdiff_t *n, | ||
|  |                                  ptrdiff_t howmany, ptrdiff_t block, ptrdiff_t tblock, | ||
|  |                                  fftw_complex *in, fftw_complex *out, | ||
|  |                                  MPI_Comm comm, int sign, unsigned flags); | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <span id="index-MPI-communicator-2"></span> | ||
|  | <span id="index-collective-function-4"></span> | ||
|  | <p>These are similar to their serial counterparts (see <a href="Complex-DFTs.html">Complex DFTs</a>) | ||
|  | in specifying the dimensions, sign, and flags of the transform.  The | ||
|  | <code>comm</code> argument gives an MPI communicator that specifies the set | ||
|  | of processes to participate in the transform; plan creation is a | ||
|  | collective function that must be called for all processes in the | ||
|  | communicator.  The <code>in</code> and <code>out</code> pointers refer only to a | ||
|  | portion of the overall transform data (see <a href="MPI-Data-Distribution.html">MPI Data Distribution</a>) | ||
|  | as specified by the ‘<samp>local_size</samp>’ functions in the previous | ||
|  | section.  Unless <code>flags</code> contains <code>FFTW_ESTIMATE</code>, these | ||
|  | arrays are overwritten during plan creation as for the serial | ||
|  | interface.  For multi-dimensional transforms, any dimensions <code>> | ||
|  | 1</code> are supported; for one-dimensional transforms, only composite | ||
|  | (non-prime) <code>n0</code> are currently supported (unlike the serial | ||
|  | FFTW).  Requesting an unsupported transform size will yield a | ||
|  | <code>NULL</code> plan.  (As in the serial interface, highly composite sizes | ||
|  | generally yield the best performance.) | ||
|  | </p> | ||
|  | <span id="index-advanced-interface-6"></span> | ||
|  | <span id="index-FFTW_005fMPI_005fDEFAULT_005fBLOCK-2"></span> | ||
|  | <span id="index-stride-3"></span> | ||
|  | <p>The advanced-interface <code>fftw_mpi_plan_many_dft</code> additionally | ||
|  | allows you to specify the block sizes for the first dimension | ||
|  | (<code>block</code>) of the n<sub>0</sub> × n<sub>1</sub> × n<sub>2</sub> × … × n<sub>d-1</sub> | ||
|  |  input data and the first dimension | ||
|  | (<code>tblock</code>) of the n<sub>1</sub> × n<sub>0</sub> × n<sub>2</sub> ×…× n<sub>d-1</sub> | ||
|  |  transposed data (at intermediate | ||
|  | steps of the transform, and for the output if | ||
|  | <code>FFTW_TRANSPOSED_OUT</code> is specified in <code>flags</code>).  These must | ||
|  | be the same block sizes as were passed to the corresponding | ||
|  | ‘<samp>local_size</samp>’ function; you can pass <code>FFTW_MPI_DEFAULT_BLOCK</code> | ||
|  | to use FFTW’s default block size as in the basic interface.  Also, the | ||
|  | <code>howmany</code> parameter specifies that the transform is of contiguous | ||
|  | <code>howmany</code>-tuples rather than individual complex numbers; this | ||
|  | corresponds to the same parameter in the serial advanced interface | ||
|  | (see <a href="Advanced-Complex-DFTs.html">Advanced Complex DFTs</a>) with <code>stride = howmany</code> and | ||
|  | <code>dist = 1</code>. | ||
|  | </p> | ||
|  | <span id="MPI-flags"></span><h4 class="subsubheading">MPI flags</h4> | ||
|  | 
 | ||
|  | <p>The <code>flags</code> can be any of those for the serial FFTW | ||
|  | (see <a href="Planner-Flags.html">Planner Flags</a>), and in addition may include one or more of | ||
|  | the following MPI-specific flags, which improve performance at the | ||
|  | cost of changing the output or input data formats. | ||
|  | </p> | ||
|  | <ul> | ||
|  | <li> <span id="index-FFTW_005fMPI_005fSCRAMBLED_005fOUT-2"></span> | ||
|  | <span id="index-FFTW_005fMPI_005fSCRAMBLED_005fIN-2"></span> | ||
|  | <code>FFTW_MPI_SCRAMBLED_OUT</code>, <code>FFTW_MPI_SCRAMBLED_IN</code>: valid for | ||
|  | 1d transforms only, these flags indicate that the output/input of the | ||
|  | transform are in an undocumented “scrambled” order.  A forward | ||
|  | <code>FFTW_MPI_SCRAMBLED_OUT</code> transform can be inverted by a backward | ||
|  | <code>FFTW_MPI_SCRAMBLED_IN</code> (times the usual 1/<i>N</i> normalization). | ||
|  | See <a href="One_002ddimensional-distributions.html">One-dimensional distributions</a>. | ||
|  | 
 | ||
|  | </li><li> <span id="index-FFTW_005fMPI_005fTRANSPOSED_005fOUT-2"></span> | ||
|  | <span id="index-FFTW_005fMPI_005fTRANSPOSED_005fIN-2"></span> | ||
|  | <code>FFTW_MPI_TRANSPOSED_OUT</code>, <code>FFTW_MPI_TRANSPOSED_IN</code>: valid | ||
|  | for multidimensional (<code>rnk > 1</code>) transforms only, these flags | ||
|  | specify that the output or input of an n<sub>0</sub> × n<sub>1</sub> × n<sub>2</sub> × … × n<sub>d-1</sub> | ||
|  |  transform is | ||
|  | transposed to n<sub>1</sub> × n<sub>0</sub> × n<sub>2</sub> ×…× n<sub>d-1</sub> | ||
|  | .  See <a href="Transposed-distributions.html">Transposed distributions</a>. | ||
|  | 
 | ||
|  | </li></ul> | ||
|  | 
 | ||
|  | <span id="Real_002ddata-MPI-DFTs"></span><h4 class="subsubheading">Real-data MPI DFTs</h4> | ||
|  | 
 | ||
|  | <span id="index-r2c-4"></span> | ||
|  | <p>Plans for real-input/output (r2c/c2r) DFTs (see <a href="Multi_002ddimensional-MPI-DFTs-of-Real-Data.html">Multi-dimensional MPI DFTs of Real Data</a>) are created by: | ||
|  | </p> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005fr2c_005f2d"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005fr2c_005f2d-1"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005fr2c_005f3d"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005fr2c"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005fc2r_005f2d"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005fc2r_005f2d-1"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005fc2r_005f3d"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fdft_005fc2r"></span> | ||
|  | <div class="example"> | ||
|  | <pre class="example">fftw_plan fftw_mpi_plan_dft_r2c_2d(ptrdiff_t n0, ptrdiff_t n1,  | ||
|  |                                    double *in, fftw_complex *out, | ||
|  |                                    MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_r2c_2d(ptrdiff_t n0, ptrdiff_t n1,  | ||
|  |                                    double *in, fftw_complex *out, | ||
|  |                                    MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_r2c_3d(ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t n2, | ||
|  |                                    double *in, fftw_complex *out, | ||
|  |                                    MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_r2c(int rnk, const ptrdiff_t *n, | ||
|  |                                 double *in, fftw_complex *out, | ||
|  |                                 MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_c2r_2d(ptrdiff_t n0, ptrdiff_t n1,  | ||
|  |                                    fftw_complex *in, double *out, | ||
|  |                                    MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_c2r_2d(ptrdiff_t n0, ptrdiff_t n1,  | ||
|  |                                    fftw_complex *in, double *out, | ||
|  |                                    MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_c2r_3d(ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t n2, | ||
|  |                                    fftw_complex *in, double *out, | ||
|  |                                    MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_dft_c2r(int rnk, const ptrdiff_t *n, | ||
|  |                                 fftw_complex *in, double *out, | ||
|  |                                 MPI_Comm comm, unsigned flags); | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <p>Similar to the serial interface (see <a href="Real_002ddata-DFTs.html">Real-data DFTs</a>), these | ||
|  | transform logically n<sub>0</sub> × n<sub>1</sub> × n<sub>2</sub> × … × n<sub>d-1</sub> | ||
|  |  real data to/from n<sub>0</sub> × n<sub>1</sub> × n<sub>2</sub> × … × (n<sub>d-1</sub>/2 + 1) | ||
|  |  complex | ||
|  | data, representing the non-redundant half of the conjugate-symmetry | ||
|  | output of a real-input DFT (see <a href="Multi_002ddimensional-Transforms.html">Multi-dimensional Transforms</a>). | ||
|  | However, the real array must be stored within a padded n<sub>0</sub> × n<sub>1</sub> × n<sub>2</sub> × … × [2 (n<sub>d-1</sub>/2 + 1)] | ||
|  | 
 | ||
|  | array (much like the in-place serial r2c transforms, but here for | ||
|  | out-of-place transforms as well). Currently, only multi-dimensional | ||
|  | (<code>rnk > 1</code>) r2c/c2r transforms are supported (requesting a plan | ||
|  | for <code>rnk = 1</code> will yield <code>NULL</code>).  As explained above | ||
|  | (see <a href="Multi_002ddimensional-MPI-DFTs-of-Real-Data.html">Multi-dimensional MPI DFTs of Real Data</a>), the data | ||
|  | distribution of both the real and complex arrays is given by the | ||
|  | ‘<samp>local_size</samp>’ function called for the dimensions of the | ||
|  | <em>complex</em> array.  Similar to the other planning functions, the | ||
|  | input and output arrays are overwritten when the plan is created | ||
|  | except in <code>FFTW_ESTIMATE</code> mode. | ||
|  | </p> | ||
|  | <p>As for the complex DFTs above, there is an advance interface that | ||
|  | allows you to manually specify block sizes and to transform contiguous | ||
|  | <code>howmany</code>-tuples of real/complex numbers: | ||
|  | </p> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fmany_005fdft_005fr2c"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fmany_005fdft_005fc2r"></span> | ||
|  | <div class="example"> | ||
|  | <pre class="example">fftw_plan fftw_mpi_plan_many_dft_r2c | ||
|  |               (int rnk, const ptrdiff_t *n, ptrdiff_t howmany, | ||
|  |                ptrdiff_t iblock, ptrdiff_t oblock, | ||
|  |                double *in, fftw_complex *out, | ||
|  |                MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_many_dft_c2r | ||
|  |               (int rnk, const ptrdiff_t *n, ptrdiff_t howmany, | ||
|  |                ptrdiff_t iblock, ptrdiff_t oblock, | ||
|  |                fftw_complex *in, double *out, | ||
|  |                MPI_Comm comm, unsigned flags);                | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <span id="MPI-r2r-transforms"></span><h4 class="subsubheading">MPI r2r transforms</h4> | ||
|  | 
 | ||
|  | <span id="index-r2r-4"></span> | ||
|  | <p>There are corresponding plan-creation routines for r2r | ||
|  | transforms (see <a href="More-DFTs-of-Real-Data.html">More DFTs of Real Data</a>), currently supporting | ||
|  | multidimensional (<code>rnk > 1</code>) transforms only (<code>rnk = 1</code> will | ||
|  | yield a <code>NULL</code> plan): | ||
|  | </p> | ||
|  | <div class="example"> | ||
|  | <pre class="example">fftw_plan fftw_mpi_plan_r2r_2d(ptrdiff_t n0, ptrdiff_t n1, | ||
|  |                                double *in, double *out, | ||
|  |                                MPI_Comm comm, | ||
|  |                                fftw_r2r_kind kind0, fftw_r2r_kind kind1, | ||
|  |                                unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_r2r_3d(ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t n2, | ||
|  |                                double *in, double *out, | ||
|  |                                MPI_Comm comm, | ||
|  |                                fftw_r2r_kind kind0, fftw_r2r_kind kind1, fftw_r2r_kind kind2, | ||
|  |                                unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_r2r(int rnk, const ptrdiff_t *n, | ||
|  |                             double *in, double *out, | ||
|  |                             MPI_Comm comm, const fftw_r2r_kind *kind,  | ||
|  |                             unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_many_r2r(int rnk, const ptrdiff_t *n, | ||
|  |                                  ptrdiff_t iblock, ptrdiff_t oblock, | ||
|  |                                  double *in, double *out, | ||
|  |                                  MPI_Comm comm, const fftw_r2r_kind *kind,  | ||
|  |                                  unsigned flags); | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <p>The parameters are much the same as for the complex DFTs above, except | ||
|  | that the arrays are of real numbers (and hence the outputs of the | ||
|  | ‘<samp>local_size</samp>’ data-distribution functions should be interpreted as | ||
|  | counts of real rather than complex numbers).  Also, the <code>kind</code> | ||
|  | parameters specify the r2r kinds along each dimension as for the | ||
|  | serial interface (see <a href="Real_002dto_002dReal-Transform-Kinds.html">Real-to-Real Transform Kinds</a>).  See <a href="Other-Multi_002ddimensional-Real_002ddata-MPI-Transforms.html">Other Multi-dimensional Real-data MPI Transforms</a>. | ||
|  | </p> | ||
|  | <span id="MPI-transposition"></span><h4 class="subsubheading">MPI transposition</h4> | ||
|  | <span id="index-transpose-5"></span> | ||
|  | 
 | ||
|  | <p>FFTW also provides routines to plan a transpose of a distributed | ||
|  | <code>n0</code> by <code>n1</code> array of real numbers, or an array of | ||
|  | <code>howmany</code>-tuples of real numbers with specified block sizes | ||
|  | (see <a href="FFTW-MPI-Transposes.html">FFTW MPI Transposes</a>): | ||
|  | </p> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005ftranspose-1"></span> | ||
|  | <span id="index-fftw_005fmpi_005fplan_005fmany_005ftranspose-1"></span> | ||
|  | <div class="example"> | ||
|  | <pre class="example">fftw_plan fftw_mpi_plan_transpose(ptrdiff_t n0, ptrdiff_t n1, | ||
|  |                                   double *in, double *out, | ||
|  |                                   MPI_Comm comm, unsigned flags); | ||
|  | fftw_plan fftw_mpi_plan_many_transpose | ||
|  |                 (ptrdiff_t n0, ptrdiff_t n1, ptrdiff_t howmany, | ||
|  |                  ptrdiff_t block0, ptrdiff_t block1, | ||
|  |                  double *in, double *out, MPI_Comm comm, unsigned flags); | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <span id="index-new_002darray-execution-2"></span> | ||
|  | <span id="index-fftw_005fmpi_005fexecute_005fr2r-1"></span> | ||
|  | <p>These plans are used with the <code>fftw_mpi_execute_r2r</code> new-array | ||
|  | execute function (see <a href="Using-MPI-Plans.html">Using MPI Plans</a>), since they count as (rank | ||
|  | zero) r2r plans from FFTW’s perspective. | ||
|  | </p> | ||
|  | <hr> | ||
|  | <div class="header"> | ||
|  | <p> | ||
|  | Next: <a href="MPI-Wisdom-Communication.html" accesskey="n" rel="next">MPI Wisdom Communication</a>, Previous: <a href="MPI-Data-Distribution-Functions.html" accesskey="p" rel="prev">MPI Data Distribution Functions</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> |