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Add FFTW 3.3.8 source, and a Linux build
author Chris Cannam <cannam@all-day-breakfast.com>
date Tue, 19 Nov 2019 14:52:55 +0000
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3 <!-- This manual is for FFTW
4 (version 3.3.8, 24 May 2018).
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6 Copyright (C) 2003 Matteo Frigo.
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8 Copyright (C) 2003 Massachusetts Institute of Technology.
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25 <title>FFTW 3.3.8: Wisdom of Fortran?</title>
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35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
36 <link href="Calling-FFTW-from-Legacy-Fortran.html#Calling-FFTW-from-Legacy-Fortran" rel="up" title="Calling FFTW from Legacy Fortran">
37 <link href="Upgrading-from-FFTW-version-2.html#Upgrading-from-FFTW-version-2" rel="next" title="Upgrading from FFTW version 2">
38 <link href="Fortran-Examples.html#Fortran-Examples" rel="prev" title="Fortran Examples">
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71 <a name="Wisdom-of-Fortran_003f"></a>
72 <div class="header">
73 <p>
74 Previous: <a href="Fortran-Examples.html#Fortran-Examples" accesskey="p" rel="prev">Fortran Examples</a>, Up: <a href="Calling-FFTW-from-Legacy-Fortran.html#Calling-FFTW-from-Legacy-Fortran" accesskey="u" rel="up">Calling FFTW from Legacy Fortran</a> &nbsp; [<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>
75 </div>
76 <hr>
77 <a name="Wisdom-of-Fortran_003f-1"></a>
78 <h3 class="section">8.5 Wisdom of Fortran?</h3>
79
80 <p>In this section, we discuss how one can import/export FFTW wisdom
81 (saved plans) to/from a Fortran program; we assume that the reader is
82 already familiar with wisdom, as described in <a href="Words-of-Wisdom_002dSaving-Plans.html#Words-of-Wisdom_002dSaving-Plans">Words of Wisdom-Saving Plans</a>.
83 </p>
84 <a name="index-portability-8"></a>
85 <p>The basic problem is that is difficult to (portably) pass files and
86 strings between Fortran and C, so we cannot provide a direct Fortran
87 equivalent to the <code>fftw_export_wisdom_to_file</code>, etcetera,
88 functions. Fortran interfaces <em>are</em> provided for the functions
89 that do not take file/string arguments, however:
90 <code>dfftw_import_system_wisdom</code>, <code>dfftw_import_wisdom</code>,
91 <code>dfftw_export_wisdom</code>, and <code>dfftw_forget_wisdom</code>.
92 <a name="index-dfftw_005fimport_005fsystem_005fwisdom"></a>
93 <a name="index-dfftw_005fimport_005fwisdom"></a>
94 <a name="index-dfftw_005fexport_005fwisdom"></a>
95 <a name="index-dfftw_005fforget_005fwisdom"></a>
96 </p>
97
98 <p>So, for example, to import the system-wide wisdom, you would do:
99 </p>
100 <div class="example">
101 <pre class="example"> integer isuccess
102 call dfftw_import_system_wisdom(isuccess)
103 </pre></div>
104
105 <p>As usual, the C return value is turned into a first parameter;
106 <code>isuccess</code> is non-zero on success and zero on failure (e.g. if
107 there is no system wisdom installed).
108 </p>
109 <p>If you want to import/export wisdom from/to an arbitrary file or
110 elsewhere, you can employ the generic <code>dfftw_import_wisdom</code> and
111 <code>dfftw_export_wisdom</code> functions, for which you must supply a
112 subroutine to read/write one character at a time. The FFTW package
113 contains an example file <code>doc/f77_wisdom.f</code> demonstrating how to
114 implement <code>import_wisdom_from_file</code> and
115 <code>export_wisdom_to_file</code> subroutines in this way. (These routines
116 cannot be compiled into the FFTW library itself, lest all FFTW-using
117 programs be required to link with the Fortran I/O library.)
118 </p>
119
120
121 </body>
122 </html>