fftw2d
(Package: fftwtools) :
Compute a two-dimensional FFT on a matrix using FFTW3
Computes two-dimensional FFT on a matrix using the FFTW3 libraries. Use fftw_r2c_2d(x, HermConj=0) for real to complex FFT. This will return the result without the "Hermitian" redundancy. These functions follow the R convention when returning the inverse of the FFT. For the two-dimension fft, the inverse is currently requires the entire matrix, including the redundant complex conjugate.
mvfftw
(Package: fftwtools) :
Compute the FFT on each column of a matrix using FFTW3
This will compute the FFT of each column of a matrix using the FFTW3 libraries. Use mvfftw_r2c(x, HermConj=0) for real to complex fft. This will return the result without the redundant complex conjugate. This follows the R convention for returning the unscaled inverse of the FFT. The function mvfftw_c2r(res, HermConj=0, n=dim(x)[1]) will invert the FFT from the result not containing the "Hermitian" redundant conjugate. You must specify, n, the column dimension of the original data–the column length of the original data–if the redundant complex conjugate is not included.
These functions compute the FFT using the FFTW3 libraries. Use fftw_r2c(x, HermConj=0) for real to complex fft. This will return the result without the redundant complex conjugate. This follows the R convention for returning the unscaled inverse of the FFT. The function fftw_c2r(res, HermConj=0, n=length(x)) will invert the FFT from the result not containing the redundant complex conjugate. You must specify, n, the dimension of the original data–length–if the redundant complex conjugate is not included.
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