annotate src/fftw-3.3.3/doc/html/Wisdom-of-Fortran_003f.html @ 83:ae30d91d2ffe

Replace these with versions built using an older toolset (so as to avoid ABI compatibilities when linking on Ubuntu 14.04 for packaging purposes)
author Chris Cannam
date Fri, 07 Feb 2020 11:51:13 +0000
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Chris@10 3 <title>Wisdom of Fortran? - FFTW 3.3.3</title>
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Chris@10 48 <a name="Wisdom-of-Fortran%3f"></a>
Chris@10 49 <a name="Wisdom-of-Fortran_003f"></a>
Chris@10 50 <p>
Chris@10 51 Previous:&nbsp;<a rel="previous" accesskey="p" href="Fortran-Examples.html#Fortran-Examples">Fortran Examples</a>,
Chris@10 52 Up:&nbsp;<a rel="up" accesskey="u" href="Calling-FFTW-from-Legacy-Fortran.html#Calling-FFTW-from-Legacy-Fortran">Calling FFTW from Legacy Fortran</a>
Chris@10 53 <hr>
Chris@10 54 </div>
Chris@10 55
Chris@10 56 <h3 class="section">8.5 Wisdom of Fortran?</h3>
Chris@10 57
Chris@10 58 <p>In this section, we discuss how one can import/export FFTW wisdom
Chris@10 59 (saved plans) to/from a Fortran program; we assume that the reader is
Chris@10 60 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>.
Chris@10 61
Chris@10 62 <p><a name="index-portability-598"></a>The basic problem is that is difficult to (portably) pass files and
Chris@10 63 strings between Fortran and C, so we cannot provide a direct Fortran
Chris@10 64 equivalent to the <code>fftw_export_wisdom_to_file</code>, etcetera,
Chris@10 65 functions. Fortran interfaces <em>are</em> provided for the functions
Chris@10 66 that do not take file/string arguments, however:
Chris@10 67 <code>dfftw_import_system_wisdom</code>, <code>dfftw_import_wisdom</code>,
Chris@10 68 <code>dfftw_export_wisdom</code>, and <code>dfftw_forget_wisdom</code>.
Chris@10 69 <a name="index-dfftw_005fimport_005fsystem_005fwisdom-599"></a><a name="index-dfftw_005fimport_005fwisdom-600"></a><a name="index-dfftw_005fexport_005fwisdom-601"></a><a name="index-dfftw_005fforget_005fwisdom-602"></a>
Chris@10 70
Chris@10 71 <p>So, for example, to import the system-wide wisdom, you would do:
Chris@10 72
Chris@10 73 <pre class="example"> integer isuccess
Chris@10 74 call dfftw_import_system_wisdom(isuccess)
Chris@10 75 </pre>
Chris@10 76 <p>As usual, the C return value is turned into a first parameter;
Chris@10 77 <code>isuccess</code> is non-zero on success and zero on failure (e.g. if
Chris@10 78 there is no system wisdom installed).
Chris@10 79
Chris@10 80 <p>If you want to import/export wisdom from/to an arbitrary file or
Chris@10 81 elsewhere, you can employ the generic <code>dfftw_import_wisdom</code> and
Chris@10 82 <code>dfftw_export_wisdom</code> functions, for which you must supply a
Chris@10 83 subroutine to read/write one character at a time. The FFTW package
Chris@10 84 contains an example file <code>doc/f77_wisdom.f</code> demonstrating how to
Chris@10 85 implement <code>import_wisdom_from_file</code> and
Chris@10 86 <code>export_wisdom_to_file</code> subroutines in this way. (These routines
Chris@10 87 cannot be compiled into the FFTW library itself, lest all FFTW-using
Chris@10 88 programs be required to link with the Fortran I/O library.)
Chris@10 89
Chris@10 90 </body></html>
Chris@10 91