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			94 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
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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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|  | Next: <a href="FFTW-Execution-in-Fortran.html" accesskey="n" rel="next">FFTW Execution in Fortran</a>, Previous: <a href="Fortran_002dinterface-routines.html" accesskey="p" rel="prev">Fortran-interface routines</a>, Up: <a href="Calling-FFTW-from-Legacy-Fortran.html" accesskey="u" rel="up">Calling FFTW from Legacy Fortran</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="FFTW-Constants-in-Fortran-1"></span><h3 class="section">8.2 FFTW Constants in Fortran</h3> | ||
|  | 
 | ||
|  | <p>When creating plans in FFTW, a number of constants are used to specify | ||
|  | options, such as <code>FFTW_MEASURE</code> or <code>FFTW_ESTIMATE</code>.  The | ||
|  | same constants must be used with the wrapper routines, but of course the | ||
|  | C header files where the constants are defined can’t be incorporated | ||
|  | directly into Fortran code. | ||
|  | </p> | ||
|  | <p>Instead, we have placed Fortran equivalents of the FFTW constant | ||
|  | definitions in the file <code>fftw3.f</code>, which can be found in the same | ||
|  | directory as <code>fftw3.h</code>.  If your Fortran compiler supports a | ||
|  | preprocessor of some sort, you should be able to <code>include</code> or | ||
|  | <code>#include</code> this file; otherwise, you can paste it directly into | ||
|  | your code. | ||
|  | </p> | ||
|  | <span id="index-flags-9"></span> | ||
|  | <p>In C, you combine different flags (like <code>FFTW_PRESERVE_INPUT</code> and | ||
|  | <code>FFTW_MEASURE</code>) using the ‘<samp><code>|</code></samp>’ operator; in Fortran | ||
|  | you should just use ‘<samp><code>+</code></samp>’.  (Take care not to add in the | ||
|  | same flag more than once, though.  Alternatively, you can use the | ||
|  | <code>ior</code> intrinsic function standardized in Fortran 95.) | ||
|  | </p> | ||
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