PDA_NFFTB

Backward FFT of N-dimensional complex array

Description:

The supplied Fourier coefficients in X and Y are replaced by the corresponding spatial data obtained by doing an inverse Fourier transform. See the forward FFT routine PDA_NFFTF for more details.

Invocation

CALL PDA_NFFTB( NDIM, DIM, X, Y, WORK, ISTAT )

Arguments

NDIM = INTEGER (Given)
The number of dimensions. This should be no more than 20.
DIM( NDIM ) = INTEGER (Given)
The size of each dimension.
X( * ) = REAL (Given and Returned)
Supplied holding the real parts of the Fourier coefficients. Returned holding the real parts of the spatial data. The array should have the number of elements implied by NDIM and DIM.
Y( * ) = REAL (Given and Returned)
Supplied holding the imaginary parts of the Fourier coefficients. Returned holding the imaginary parts of the spatial data. The array should have the number of elements implied by NDIM and DIM.
WORK( * ) = REAL (Given and Returned)
A work array. This should have at least ( 6*DimMax + 15 ) elements where DimMax is the maximum of the values supplied in DIM.
ISTAT = INTEGER (Returned)
If the value of NDIM is greater than 20 or less than 1, then ISTAT is returned equal to 1, and the values in X and Y are left unchanged. Otherwise, ISTAT is returned equal to 0.

Implementation Status:

A double precision version PDA_DNFFTB of the routine exists.