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			104 lines
		
	
	
		
			4.4 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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|  | <title>MPI Initialization (FFTW 3.3.10)</title> | ||
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|  | <span id="MPI-Initialization"></span><div class="header"> | ||
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|  | Next: <a href="Using-MPI-Plans.html" accesskey="n" rel="next">Using MPI Plans</a>, Previous: <a href="MPI-Files-and-Data-Types.html" accesskey="p" rel="prev">MPI Files and Data Types</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> | ||
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|  | <span id="MPI-Initialization-1"></span><h4 class="subsection">6.12.2 MPI Initialization</h4> | ||
|  | 
 | ||
|  | <p>Before calling any other FFTW MPI (‘<samp>fftw_mpi_</samp>’) function, and | ||
|  | before importing any wisdom for MPI problems, you must call: | ||
|  | </p> | ||
|  | <span id="index-fftw_005fmpi_005finit-4"></span> | ||
|  | <div class="example"> | ||
|  | <pre class="example">void fftw_mpi_init(void); | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <span id="index-fftw_005finit_005fthreads-3"></span> | ||
|  | <p>If FFTW threads support is used, however, <code>fftw_mpi_init</code> should | ||
|  | be called <em>after</em> <code>fftw_init_threads</code> (see <a href="Combining-MPI-and-Threads.html">Combining MPI and Threads</a>).  Calling <code>fftw_mpi_init</code> additional times (before | ||
|  | <code>fftw_mpi_cleanup</code>) has no effect. | ||
|  | </p> | ||
|  | 
 | ||
|  | <p>If you want to deallocate all persistent data and reset FFTW to the | ||
|  | pristine state it was in when you started your program, you can call: | ||
|  | </p> | ||
|  | <span id="index-fftw_005fmpi_005fcleanup-1"></span> | ||
|  | <div class="example"> | ||
|  | <pre class="example">void fftw_mpi_cleanup(void); | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <span id="index-fftw_005fcleanup-1"></span> | ||
|  | <p>(This calls <code>fftw_cleanup</code>, so you need not call the serial | ||
|  | cleanup routine too, although it is safe to do so.)  After calling | ||
|  | <code>fftw_mpi_cleanup</code>, all existing plans become undefined, and you | ||
|  | should not attempt to execute or destroy them.  You must call | ||
|  | <code>fftw_mpi_init</code> again after <code>fftw_mpi_cleanup</code> if you want | ||
|  | to resume using the MPI FFTW routines. | ||
|  | </p> | ||
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