How to use the FFTW Library

https://www.hoffman2.idre.ucla.edu/fftw/

Using FFTW 3 from C and C++

In your program include:

#include <fftw3.h>

and call the appropriate fftw3 functions.

You may also include:

#include <complex.h>

to handle complex numbers.

There are three versions of the fftw3 library depending on precision. The APIs for each differ slightly because of the precision differences:

Precision	Library	Example Program (FFT of a sine wave)
Double	fftw3	fftw3-test.c
Single	fftw3f	fftw3f-test.c
Long Double	fftw3l	fftw3l-test.c

To compile and link either enter:

icc pgm.c -I$FFTW3_HOME/include -L$FFTW3_HOME/lib -llib [-static-intel] -o pgm

or:

gcc -std=c99 pgm.c -I$FFTW3_HOME/include -L$FFTW3_HOME/lib -llib -lm [-static] -o pgm

depending upon the compiler you want to use.

• Replace pgm.c with the name of the file containing your source code
• Replace pgm with the name of the executable to be created
• Replace lib with one of the three fftw3 libraries: fftw3, fftw3f or fftw3l
• Set FFTW3_HOME /u/local/apps/fftw3/current

If you omit -static, you will have to set the LD_LIBRARY_PATH environment variable at run time to include $FFTW_HOME/lib.

You can either set an environment variable or replace $FFTW3_HOME in the command shown above.