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How to use FFTW
(Redirected from How-to-compute-FFT-using-FFTW-in-Qt)
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Getting Started
Note that this is done on an Ubuntu operating system, on Windows some steps are different.
- Step 1: Download FFTW from http://www.fftw.org/download.html
- 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