CRFFT2(3F)
CRFFT2 - Calculate a complex-to-real Fourier synthesis/analysis.
As shipped in IRIX 6.5. First release of IRIX 6.5.
NAME CRFFT2 - Calculate a complex-to-real Fourier synthesis/analysis. DESCRIPTION A subroutine that calculates a Fourier synthesis if the sign of IX is negative and a Fourier analysis if the sign of IX is positive. Call from FORTRAN: CALL CRFFT2(init,ix,n,x,work,y) init <>0 Generates sine and cosine tables in WORK = 0 Calculates Fourier transforms using sine and cosine tables of previous call. ix > 0 Calculates Fourier analysis <=0 Calculates Fourier synthesis. n Size of Fourier transform; 2**m where 2<=m. x Input vector. Vector of (n/2)+1 complex values. work Working storage. Vector of (3/2)n+2 complex values. y Result vector. Vector of n complex values. For equations and other additional information, see the CRAY-1 Computer Systems - Library Reference Manual, SR-0014, page 4-53.