RCFFT2(3F)
RCFFT2 - Calculate a real-to-complex Fourier synthesis/analysis.
As shipped in IRIX 6.5.7. Unchanged since IRIX 6.5.
NAME RCFFT2 - Calculate a real-to-complex 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 RCFFT2(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 real values. work Working storage. Vector of (3/2)n+2 complex values. y Result vector. Vector of (n/2)+1 complex values. For equations and other additional information, see the CRAY-1 Computer Systems - Library Reference Manual, SR-0014, page 4-52.