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			116 lines
		
	
	
		
			5.9 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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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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into another language, under the above conditions for modified versions,
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except that this permission notice may be stated in a translation
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approved by the Free Software Foundation. -->
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<title>Calling FFTW from Legacy Fortran (FFTW 3.3.10)</title>
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<link href="Concept-Index.html" rel="index" title="Concept Index">
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<link href="Fortran_002dinterface-routines.html" rel="next" title="Fortran-interface routines">
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<span id="Calling-FFTW-from-Legacy-Fortran"></span><div class="header">
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<p>
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Next: <a href="Upgrading-from-FFTW-version-2.html" accesskey="n" rel="next">Upgrading from FFTW version 2</a>, Previous: <a href="Calling-FFTW-from-Modern-Fortran.html" accesskey="p" rel="prev">Calling FFTW from Modern Fortran</a>, Up: <a href="index.html" accesskey="u" rel="up">Top</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="Calling-FFTW-from-Legacy-Fortran-1"></span><h2 class="chapter">8 Calling FFTW from Legacy Fortran</h2>
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<span id="index-Fortran-interface-3"></span>
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<p>This chapter describes the interface to FFTW callable by Fortran code
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in older compilers not supporting the Fortran 2003 C interoperability
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features (see <a href="Calling-FFTW-from-Modern-Fortran.html">Calling FFTW from Modern Fortran</a>).  This interface
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has the major disadvantage that it is not type-checked, so if you
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mistake the argument types or ordering then your program will not have
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any compiler errors, and will likely crash at runtime.  So, greater
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care is needed.  Also, technically interfacing older Fortran versions
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to C is nonstandard, but in practice we have found that the techniques
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used in this chapter have worked with all known Fortran compilers for
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many years.
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</p>
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<p>The legacy Fortran interface differs from the C interface only in the
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prefix (‘<samp>dfftw_</samp>’ instead of ‘<samp>fftw_</samp>’ in double precision) and
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a few other minor details.  This Fortran interface is included in the
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FFTW libraries by default, unless a Fortran compiler isn’t found on
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your system or <code>--disable-fortran</code> is included in the
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<code>configure</code> flags.  We assume here that the reader is already
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familiar with the usage of FFTW in C, as described elsewhere in this
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manual.
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</p>
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<p>The MPI parallel interface to FFTW is <em>not</em> currently available
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to legacy Fortran.
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</p>
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<table class="menu" border="0" cellspacing="0">
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<tr><td align="left" valign="top">• <a href="Fortran_002dinterface-routines.html" accesskey="1">Fortran-interface routines</a></td><td>  </td><td align="left" valign="top">
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</td></tr>
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<tr><td align="left" valign="top">• <a href="FFTW-Constants-in-Fortran.html" accesskey="2">FFTW Constants in Fortran</a></td><td>  </td><td align="left" valign="top">
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</td></tr>
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<tr><td align="left" valign="top">• <a href="FFTW-Execution-in-Fortran.html" accesskey="3">FFTW Execution in Fortran</a></td><td>  </td><td align="left" valign="top">
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Fortran-Examples.html" accesskey="4">Fortran Examples</a></td><td>  </td><td align="left" valign="top">
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Wisdom-of-Fortran_003f.html" accesskey="5">Wisdom of Fortran?</a></td><td>  </td><td align="left" valign="top">
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</td></tr>
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</table>
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<div class="header">
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<p>
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Next: <a href="Upgrading-from-FFTW-version-2.html" accesskey="n" rel="next">Upgrading from FFTW version 2</a>, Previous: <a href="Calling-FFTW-from-Modern-Fortran.html" accesskey="p" rel="prev">Calling FFTW from Modern Fortran</a>, Up: <a href="index.html" accesskey="u" rel="up">Top</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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