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|  | (version 3.3.10, 10 December 2020). | ||
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|  | Copyright (C) 2003 Matteo Frigo. | ||
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|  | <span id="Defining-an-FFTW-module"></span><div class="header"> | ||
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|  | Previous: <a href="Accessing-the-wisdom-API-from-Fortran.html" accesskey="p" rel="prev">Accessing the wisdom API from Fortran</a>, Up: <a href="Calling-FFTW-from-Modern-Fortran.html" accesskey="u" rel="up">Calling FFTW from Modern 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="Defining-an-FFTW-module-1"></span><h3 class="section">7.7 Defining an FFTW module</h3> | ||
|  | 
 | ||
|  | <p>Rather than using the <code>include</code> statement to include the | ||
|  | <code>fftw3.f03</code> interface file in any subroutine where you want to | ||
|  | use FFTW, you might prefer to define an FFTW Fortran module.  FFTW | ||
|  | does not install itself as a module, primarily because | ||
|  | <code>fftw3.f03</code> can be shared between different Fortran compilers while | ||
|  | modules (in general) cannot.  However, it is trivial to define your | ||
|  | own FFTW module if you want.  Just create a file containing: | ||
|  | </p> | ||
|  | <div class="example"> | ||
|  | <pre class="example">  module FFTW3 | ||
|  |     use, intrinsic :: iso_c_binding | ||
|  |     include 'fftw3.f03' | ||
|  |   end module | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <p>Compile this file into a module as usual for your compiler (e.g. with | ||
|  | <code>gfortran -c</code> you will get a file <code>fftw3.mod</code>).  Now, | ||
|  | instead of <code>include 'fftw3.f03'</code>, whenever you want to use FFTW | ||
|  | routines you can just do: | ||
|  | </p> | ||
|  | <div class="example"> | ||
|  | <pre class="example">  use FFTW3 | ||
|  | </pre></div> | ||
|  | 
 | ||
|  | <p>as usual for Fortran modules.  (You still need to link to the FFTW | ||
|  | library, of course.) | ||
|  | </p> | ||
|  | 
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