Qt wiki will be updated on October 12th 2023 starting at 11:30 AM (EEST) and the maintenance will last around 2-3 hours. During the maintenance the site will be unavailable.

How to use FFTW

From Qt Wiki
Jump to navigation Jump to search

Getting Started

Note that this is done on an Ubuntu operating system, on Windows some steps are different.

  • Step 2: Extract and Configure it (my path: /home/jafarabadi/Documents/fftw-3.3.4)
cd /home/jafarabadi/Documents/fftw-3.3.4
./configure
make
make install
  • Alternatively install fftw through your package manager (e.g. pacman -Sy fftw)
  • Step 3: Add library to project: first open [your_project_name].pro file in Qt Creator and add this line:
LIBS += -lfftw3
  • Step 4: Example
#include <fftw3.h>
int N;

// Set N to the number of complex elements in the input array

fftw_complex *in, *out;
in = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * N);
out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * N);

// Initialize 'in' with N complex entries

fftw_plan my_plan;
my_plan = fftw_plan_dft_1d(N, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
fftw_execute(my_plan);

// Use 'out' for something

fftw_destroy_plan(my_plan);
fftw_free(in);
fftw_free(out);

// A short tutorial:
// http://www2.math.uu.se/~figueras/Other/text/fftw_tutorial.pdf