I've been scanning all of the FFTW documentation, trying to figure out how to inverse FFT my FFT spectrum.
The documentation only mentions how to inverse FFT real-to-complex transformations, using the opposite
There are no
FFTW_INVERSE flags anywhere but I suspect that the
FFTW_FORWARD/BACKWARD transform might be what I need.
i.e. FORWARD for FFT and BACKWARD for IFFT. The documentation speaks about it flipping the sign; I remember something similar happening with the IFFT.
Is the backwards transform just an IFFT (for forward transform)? If not, how do you achieve an IFFT?