cfft_crfft2d - complex-real 2D FFT

SYNOPSIS

#include <cfft.h>

int cfft_crfft2d(scale, n1, n2, ld1, data, iopt)

float scale
int n1
int n2
int ld1
float data(ld1,n2)
int iopt

DESCRIPTION

The function, "cfft_crfft2d", preforms a complex-to-real 2D FFT.

INPUT

The parameter, "scale", specified the scale factor to be applied to the data.

The size parameters, "n1" and "n2", specifies the 2D FFT sizes. These must be setup as mixed radix values (must be even) in order to allow the FFT's to be more efficient. It is recommended to use cfft_nrfft5 to calculate these values.

The leading dimension parameter, "ld1", specifies the leading dimension of the float array.

The real array, "data", is the I/O array; it is performed "in place". The input complex data is packed into the real array in a typical half-complex format; it requires the size of data, "ld1", to be at least "n1" + 2, and "ld1" is specified in real values.

The parameter, "iopt", is used to specify any other information that is unique to a specific FFT implementation. Currently, the use is for specifying whether to measure or estimate the FFT's when using FFTW routines. The "cfft.h" header defines FFT_MEASURE and FFT_ESTIMATE, besides defining the FFT functions, as integer.

OUTPUT

The fft results are returned in the real data array and the returned value is zero "0" if successful. A value of "-1" is returned if the arguments are invalid. Otherwise, a value unique to each FFT implementation is returned.

AUTHOR

Phuong Vu, HPC
Jerry Ehlers, EPTG