Mercurial > hg > batch-feature-extraction-tool
diff Lib/fftw-3.2.1/doc/html/.svn/text-base/Fortran_002dinterface-routines.html.svn-base @ 15:585caf503ef5 tip
Tidy up for ROLI
| author | Geogaddi\David <d.m.ronan@qmul.ac.uk> |
|---|---|
| date | Tue, 17 May 2016 18:50:19 +0100 |
| parents | 636c989477e7 |
| children |
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--- a/Lib/fftw-3.2.1/doc/html/.svn/text-base/Fortran_002dinterface-routines.html.svn-base Wed May 04 11:02:59 2016 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,137 +0,0 @@ -<html lang="en"> -<head> -<title>Fortran-interface routines - FFTW 3.2.1</title> -<meta http-equiv="Content-Type" content="text/html"> -<meta name="description" content="FFTW 3.2.1"> -<meta name="generator" content="makeinfo 4.8"> -<link title="Top" rel="start" href="index.html#Top"> -<link rel="up" href="Calling-FFTW-from-Fortran.html#Calling-FFTW-from-Fortran" title="Calling FFTW from Fortran"> -<link rel="prev" href="Calling-FFTW-from-Fortran.html#Calling-FFTW-from-Fortran" title="Calling FFTW from Fortran"> -<link rel="next" href="FFTW-Constants-in-Fortran.html#FFTW-Constants-in-Fortran" title="FFTW Constants in Fortran"> -<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> -<!-- -This manual is for FFTW -(version 3.2.1, 5 February 2009). - -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. - --> -<meta http-equiv="Content-Style-Type" content="text/css"> -<style type="text/css"><!-- - pre.display { font-family:inherit } - pre.format { font-family:inherit } - pre.smalldisplay { font-family:inherit; font-size:smaller } - pre.smallformat { font-family:inherit; font-size:smaller } - pre.smallexample { font-size:smaller } - pre.smalllisp { font-size:smaller } - span.sc { font-variant:small-caps } - span.roman { font-family:serif; font-weight:normal; } - span.sansserif { font-family:sans-serif; font-weight:normal; } ---></style> -</head> -<body> -<div class="node"> -<p> -<a name="Fortran-interface-routines"></a> -<a name="Fortran_002dinterface-routines"></a> -Next: <a rel="next" accesskey="n" href="FFTW-Constants-in-Fortran.html#FFTW-Constants-in-Fortran">FFTW Constants in Fortran</a>, -Previous: <a rel="previous" accesskey="p" href="Calling-FFTW-from-Fortran.html#Calling-FFTW-from-Fortran">Calling FFTW from Fortran</a>, -Up: <a rel="up" accesskey="u" href="Calling-FFTW-from-Fortran.html#Calling-FFTW-from-Fortran">Calling FFTW from Fortran</a> -<hr> -</div> - -<h3 class="section">7.1 Fortran-interface routines</h3> - -<p>Nearly all of the FFTW functions have Fortran-callable equivalents. The -name of the Fortran routine is the same as that of the corresponding C -routine, but with the `<samp><span class="samp">fftw_</span></samp>' prefix replaced by `<samp><span class="samp">dfftw_</span></samp>'. -(The single and long-double precision versions use `<samp><span class="samp">sfftw_</span></samp>' and -`<samp><span class="samp">lfftw_</span></samp>', respectively, instead of `<samp><span class="samp">fftwf_</span></samp>' and -`<samp><span class="samp">fftwl_</span></samp>'.)<a rel="footnote" href="#fn-1" name="fnd-1"><sup>1</sup></a> - - <p>For the most part, all of the arguments to the functions are the same, -with the following exceptions: - - <ul> -<li><code>plan</code> variables (what would be of type <code>fftw_plan</code> in C), -must be declared as a type that is at least as big as a pointer -(address) on your machine. We recommend using <code>integer*8</code>. -<a name="index-portability-332"></a> -<li>Any function that returns a value (e.g. <code>fftw_plan_dft</code>) is -converted into a <em>subroutine</em>. The return value is converted into -an additional <em>first</em> parameter of this subroutine.<a rel="footnote" href="#fn-2" name="fnd-2"><sup>2</sup></a> - - <li><a name="index-column_002dmajor-333"></a>The Fortran routines expect multi-dimensional arrays to be in -<em>column-major</em> order, which is the ordinary format of Fortran -arrays (see <a href="Multi_002ddimensional-Array-Format.html#Multi_002ddimensional-Array-Format">Multi-dimensional Array Format</a>). They do this -transparently and costlessly simply by reversing the order of the -dimensions passed to FFTW, but this has one important consequence for -multi-dimensional real-complex transforms, discussed below. - - <li>Wisdom import and export is somewhat more tricky because one cannot -easily pass files or strings between C and Fortran; see <a href="Wisdom-of-Fortran_003f.html#Wisdom-of-Fortran_003f">Wisdom of Fortran?</a>. - - <li>Fortran cannot use the <code>fftw_malloc</code> dynamic-allocation routine. -If you want to exploit the SIMD FFTW (see <a href="Data-Alignment.html#Data-Alignment">Data Alignment</a>), you'll -need to figure out some other way to ensure that your arrays are at -least 16-byte aligned. - - <li><a name="index-fftw_005fiodim-334"></a><a name="index-guru-interface-335"></a>Since Fortran 77 does not have data structures, the <code>fftw_iodim</code> -structure from the guru interface (see <a href="Guru-vector-and-transform-sizes.html#Guru-vector-and-transform-sizes">Guru vector and transform sizes</a>) must be split into separate arguments. In particular, any -<code>fftw_iodim</code> array arguments in the C guru interface become three -integer array arguments (<code>n</code>, <code>is</code>, and <code>os</code>) in the -Fortran guru interface, all of whose lengths should be equal to the -corresponding <code>rank</code> argument. - - <li>The guru planner interface in Fortran does <em>not</em> do any automatic -translation between column-major and row-major; you are responsible -for setting the strides etcetera to correspond to your Fortran arrays. -However, as a slight bug that we are preserving for backwards -compatibility, the `<samp><span class="samp">plan_guru_r2r</span></samp>' in Fortran <em>does</em> reverse the -order of its <code>kind</code> array parameter, so the <code>kind</code> array -of that routine should be in the reverse of the order of the iodim -arrays (see above). - - </ul> - - <p>In general, you should take care to use Fortran data types that -correspond to (i.e. are the same size as) the C types used by FFTW. If -your C and Fortran compilers are made by the same vendor, the -correspondence is usually straightforward (i.e. <code>integer</code> -corresponds to <code>int</code>, <code>real</code> corresponds to <code>float</code>, -etcetera). The native Fortran double/single-precision complex type -should be compatible with <code>fftw_complex</code>/<code>fftwf_complex</code>. -Such simple correspondences are assumed in the examples below. -<a name="index-portability-336"></a> -<!-- --> - - <div class="footnote"> -<hr> -<h4>Footnotes</h4><p class="footnote"><small>[<a name="fn-1" href="#fnd-1">1</a>]</small> Technically, Fortran 77 identifiers are -not allowed to have more than 6 characters, nor may they contain -underscores. Any compiler that enforces this limitation doesn't deserve -to link to FFTW.</p> - - <p class="footnote"><small>[<a name="fn-2" href="#fnd-2">2</a>]</small> The -reason for this is that some Fortran implementations seem to have -trouble with C function return values, and vice versa.</p> - - <p><hr></div> - - </body></html> -