cfftc3 - initialize the trigonometric weight and factor tables or compute the three-dimensional Fast Fourier Transform (forward or inverse) of a three-dimensional complex array. =head1 SYNOPSIS
SUBROUTINE CFFTC3( IOPT, N1, N2, N3, SCALE, X, LDX1, LDX2, Y, LDY1, * LDY2, TRIGS, IFAC, WORK, LWORK, IERR) COMPLEX X(LDX1,LDX2,*), Y(LDY1,LDY2,*) INTEGER IOPT, N1, N2, N3, LDX1, LDX2, LDY1, LDY2, LWORK, IERR INTEGER IFAC(*) REAL SCALE REAL TRIGS(*), WORK(*)
SUBROUTINE CFFTC3_64( IOPT, N1, N2, N3, SCALE, X, LDX1, LDX2, Y, * LDY1, LDY2, TRIGS, IFAC, WORK, LWORK, IERR) COMPLEX X(LDX1,LDX2,*), Y(LDY1,LDY2,*) INTEGER*8 IOPT, N1, N2, N3, LDX1, LDX2, LDY1, LDY2, LWORK, IERR INTEGER*8 IFAC(*) REAL SCALE REAL TRIGS(*), WORK(*)
SUBROUTINE FFT3( IOPT, [N1], [N2], [N3], [SCALE], X, [LDX1], LDX2, * Y, [LDY1], LDY2, TRIGS, IFAC, WORK, [LWORK], IERR) COMPLEX, DIMENSION(:,:,:) :: X, Y INTEGER :: IOPT, N1, N2, N3, LDX1, LDX2, LDY1, LDY2, LWORK, IERR INTEGER, DIMENSION(:) :: IFAC REAL :: SCALE REAL, DIMENSION(:) :: TRIGS, WORK
SUBROUTINE FFT3_64( IOPT, [N1], [N2], [N3], [SCALE], X, [LDX1], * LDX2, Y, [LDY1], LDY2, TRIGS, IFAC, WORK, [LWORK], IERR) COMPLEX, DIMENSION(:,:,:) :: X, Y INTEGER(8) :: IOPT, N1, N2, N3, LDX1, LDX2, LDY1, LDY2, LWORK, IERR INTEGER(8), DIMENSION(:) :: IFAC REAL :: SCALE REAL, DIMENSION(:) :: TRIGS, WORK
#include <sunperf.h>
void cfftc3(int iopt, int n1, int n2, int n3, float scale, complex *x, int ldx1, int ldx2, complex *y, int ldy1, int ldy2, float *trigs, int *ifac, float *work, int lwork, int *ierr);
void cfftc3_64(long iopt, long n1, long n2, long n3, float scale, complex *x, long ldx1, long ldx2, complex *y, long ldy1, long ldy2, float *trigs, long *ifac, float *work, long lwork, long *ierr);
cfftc3 initializes the trigonometric weight and factor tables or computes the three-dimensional Fast Fourier Transform (forward or inverse) of a three-dimensional complex array. .Ve
N3-1 N2-1 N1-1
Y(k1,k2,k3)
= scale * SUM SUM SUM W3*W2*W1*X(j1,j2,j3)
j3=0 j2=0 j1=0 .Ve
where
k1 ranges from 0 to N1-1; k2 ranges from 0 to N2-1 and k3 ranges from 0 to N3-1
i = sqrt(-1)
isign = 1 for inverse transform or -1 for forward transform
W1 = exp(isign*i*j1*k1*2*pi/N1)
W2 = exp(isign*i*j2*k2*2*pi/N2)
W3 = exp(isign*i*j3*k3*2*pi/N3)
IOPT = 0 computes the trigonometric weight table and factor table
IOPT = -1 computes forward FFT
IOPT = +1 computes inverse FFT
0 = normal return
-1 = IOPT is not 0, 1 or -1
-2 = N1 < 0
-3 = N2 < 0
-4 = N3 < 0
-5 = (LDX1 < N1)
-6 = (LDX2 < N2)
-7 = (LDY1 < N1) or (LDY1 not equal LDX1 when X and Y are same array)
-8 = (LDY2 < N2) or (LDY2 not equal LDX2 when X and Y are same array)
-9 = (LWORK not equal 0) and (LWORK < (2*MAX(N,N2,N3) + 16*N3) * NCPUS)
-10 = memory allocation failed
fft
This routine uses Y(N1+1:LDY1,:,:)
as scratch space. Therefore, the original contents of this subarray will be lost upon returning from routine while subarray Y(1:N1,1:N2,1:N3)
contains the transform results.