Description Usage Arguments Author(s) Examples
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.
1 2 3 4 5 |
data |
(complex or real) vector to be processed |
inverse |
(integer) 1 or 0 indicating if inverse FFT is preformed. The return follows the format of the R FFT commands–the output is not scaled. |
HermConj |
(integer) 1 or 0 indicating if either "Hermitian" redundant conjugate should be returned, or that the complex to real data includes the "Hermitian" redundant conjugate. |
n |
(integer) column length of the original data set. This is required when using the inverse complex to real FFT without providing the "Hermitian" redundant conjugate. |
Karim Rahim
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | res <- fftw_r2c(1:9)
res
fftw_c2r(res)/9
res
fftw_c2r(res)/9
res <- fftw_r2c(1:10)
res
fftw_c2r(res)/10
res
fftw_c2r(res)/10
res <- fftw_r2c(1:9, HermConj=0)
res
fftw_c2r(res, HermConj=0, n=9)/9
res <- fftw_r2c(1:10, HermConj=0)
res
fftw_c2r(res, HermConj=0, n=10)/10
fftw_r2c(1:3)
fftw_c2r(fftw_r2c(1:3))/3
fftw_c2r(fftw_r2c(1:2))/2
fftw_c2r(fftw_r2c(1:4))/4
fftw_r2c(1:3, HermConj=1)
fftw_c2r(fftw_r2c(1:3, HermConj=0), HermConj=0, n=3)/3
fftw_c2r(fftw_r2c(1:4, HermConj=0), HermConj=0, n=4)/4
fftw_c2r(fftw_r2c(1:20, HermConj=0), HermConj=0, n=20)/20
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