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			120 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<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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Permission is granted to make and distribute verbatim copies of this
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manual provided the copyright notice and this permission notice are
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preserved on all copies.
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Permission is granted to copy and distribute modified versions of this
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manual under the conditions for verbatim copying, provided that the
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entire resulting derived work is distributed under the terms of a
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permission notice identical to this one.
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Permission is granted to copy and distribute translations of this manual
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approved by the Free Software Foundation. -->
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<title>Generating your own code (FFTW 3.3.10)</title>
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<link href="Installation-and-Customization.html" rel="up" title="Installation and Customization">
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<span id="Generating-your-own-code"></span><div class="header">
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<p>
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Previous: <a href="Cycle-Counters.html" accesskey="p" rel="prev">Cycle Counters</a>, Up: <a href="Installation-and-Customization.html" accesskey="u" rel="up">Installation and Customization</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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<hr>
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<span id="Generating-your-own-code-1"></span><h3 class="section">10.4 Generating your own code</h3>
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<span id="index-code-generator-1"></span>
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<p>The directory <code>genfft</code> contains the programs that were used to
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generate FFTW’s “codelets,” which are hard-coded transforms of small
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sizes.
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<span id="index-codelet-2"></span>
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We do not expect casual users to employ the generator, which is a rather
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sophisticated program that generates directed acyclic graphs of FFT
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algorithms and performs algebraic simplifications on them.  It was
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written in Objective Caml, a dialect of ML, which is available at
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<a href="http://caml.inria.fr/ocaml/index.en.html">http://caml.inria.fr/ocaml/index.en.html</a>.
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<span id="index-Caml"></span>
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</p>
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<p>If you have Objective Caml installed (along with recent versions of
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GNU <code>autoconf</code>, <code>automake</code>, and <code>libtool</code>), then you
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can change the set of codelets that are generated or play with the
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generation options.  The set of generated codelets is specified by the
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<code>{dft,rdft}/{codelets,simd}/*/Makefile.am</code> files.  For example, you can add
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efficient REDFT codelets of small sizes by modifying
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<code>rdft/codelets/r2r/Makefile.am</code>.
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<span id="index-REDFT-2"></span>
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After you modify any <code>Makefile.am</code> files, you can type <code>sh
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bootstrap.sh</code> in the top-level directory followed by <code>make</code> to
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re-generate the files.
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</p>
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<p>We do not provide more details about the code-generation process, since
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we do not expect that most users will need to generate their own code.
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However, feel free to contact us at <a href="mailto:fftw@fftw.org">fftw@fftw.org</a> if
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you are interested in the subject.
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</p>
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<span id="index-monadic-programming"></span>
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<p>You might find it interesting to learn Caml and/or some modern
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programming techniques that we used in the generator (including monadic
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programming), especially if you heard the rumor that Java and
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object-oriented programming are the latest advancement in the field.
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The internal operation of the codelet generator is described in the
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paper, “A Fast Fourier Transform Compiler,” by M. Frigo, which is
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available from the <a href="http://www.fftw.org">FFTW home page</a> and also
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appeared in the <cite>Proceedings of the 1999 ACM SIGPLAN Conference on
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Programming Language Design and Implementation (PLDI)</cite>.
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</p>
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<hr>
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<div class="header">
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<p>
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Previous: <a href="Cycle-Counters.html" accesskey="p" rel="prev">Cycle Counters</a>, Up: <a href="Installation-and-Customization.html" accesskey="u" rel="up">Installation and Customization</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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