FFTW3
Fast Fourier Transforms
FORTRAN77 Calling Examples

This directory contains examples of the use of the FFTW3 library by a FORTRAN77 calling program.

FFTW3 is a library of C routines which can compute the Fourier transform very efficiently.

FFTW3 can compute the discrete Fourier transform of:

• complex data;
• real data;
• even-symmetric real data (cosine transform);
• odd-symmetric real data (sine transform);

The length of the data is not required to be a power of 2. Any length of data can be processed.

The data is not restricted to 1 dimensional vectors. FFTW3 can handle data that is 2 or 3 dimensional. In fact, the program can handle data with any dimensionality.

The FORTRAN77 include file is in /usr/local/include. A sample copy is also available in this directory.

Usage:

At link time, you must include the FFTW3 library. An appropriate command might be

        f77 myprog.c -lfftw3
      

Related Programs:

The FFTW3 library may also be callable from a C program.

FFTPACK is a FORTRAN90 library of FFT routines.

FFTPACK5 is a FORTRAN90 library of FFT routines.

GSL is the Gnu Scientific Library, which includes a number of FFT routines.

GROMACS is a molecular dynamics package which uses the FFTW3 library.

NMS is a FORTRAN90 library which includes a number of FFT routines.

Author:

Matteo Frigo and Steven Johnson

Reference:

1. William Briggs, Van Emden Henson,
   The Discrete Fourier Transform,
   SIAM,
   LC: QA403.5 B75
2. Elbert Brigham,
   The Fast Fourier Transform and Its Applications,
   Prentice-Hall, 1988.
3. http://www.fftw.org,
   the FFTW homepage.
4. Matteo Frigo, Steven Johnson,
   User Manual for FFTW,
   fftw3.pdf.

Examples and Tests:

• fftw3.f, the FFTW3 FORTRAN77 include file, which defines various symbolic constants.
• fftw3_prb.f, a sample calling program.
• fftw3_prb.csh, commands to compile, link and run the sample calling program.
• fftw3_prb_output.txt, the output file.

You can go up one level to the FORTRAN77 source codes.