Contents
zfftzm - initialize the trigonometric weight and factor
tables or compute the one-dimensional Fast Fourier Transform
(forward or inverse) of a set of data sequences stored in a
two-dimensional double complex array.
SUBROUTINE ZFFTZM(IOPT, N1, N2, SCALE, X, LDX, Y, LDY, TRIGS, IFAC, WORK, LWORK, IERR)
INTEGER IOPT, N1, N2, LDX, LDY, IFAC(*), LWORK, IERR
DOUBLE COMPLEX X(LDX, *), Y(LDY, *)
DOUBLE PRECISION SCALE, TRIGS(*), WORK(*)
SUBROUTINE ZFFTZM_64(IOPT, N1, N2, SCALE, X, LDX, Y, LDY, TRIGS, IFAC, WORK, LWORK, IERR)
INTEGER*8 IOPT, N1, N2, LDX, LDY, IFAC(*), LWORK, IERR
DOUBLE PRECISION SCALE, TRIGS(*), WORK(*)
DOUBLE COMPLEX X(LDX, *), Y(LDY, *)
F95 INTERFACE
SUBROUTINE FFTM(IOPT, [N1], [N2], [SCALE], X, [LDX], Y, [LDY], TRIGS,
IFAC, WORK, [LWORK], IERR)
INTEGER, INTENT(IN) :: IOPT
INTEGER, INTENT(IN), OPTIONAL :: N1, N2, LDX, LDY, LWORK
REAL(8), INTENT(IN), OPTIONAL :: SCALE
COMPLEX(8), INTENT(IN), DIMENSION(:,:) :: X
COMPLEX(8), INTENT(OUT), DIMENSION(:,:) :: Y
REAL(8), INTENT(INOUT), DIMENSION(:) :: TRIGS
INTEGER, INTENT(INOUT), DIMENSION(:) :: IFAC
REAL(8), INTENT(OUT), DIMENSION(:) :: WORK
INTEGER, INTENT(OUT) :: IERR
SUBROUTINE FFTM_64(IOPT, [N1], [N2], [SCALE], X, [LDX], Y, [LDY], TRIGS, IFAC, WORK, [LWORK], IERR)
INTEGER(8), INTENT(IN) :: IOPT
INTEGER(8), INTENT(IN), OPTIONAL :: N1, N2, LDX, LDY, LWORK
REAL(8), INTENT(IN), OPTIONAL :: SCALE
COMPLEX(8), INTENT(IN), DIMENSION(:,:) :: X
COMPLEX(8), INTENT(OUT), DIMENSION(:,:) :: Y
REAL(8), INTENT(INOUT), DIMENSION(:) :: TRIGS
INTEGER(8), INTENT(INOUT), DIMENSION(:) :: IFAC
REAL(8), INTENT(OUT), DIMENSION(:) :: WORK
INTEGER(8), INTENT(OUT) :: IERR
C INTERFACE
#include <sunperf.h>
void zfftzm_ (int *iopt, int *m, int *n, double *scale,
doublecomplex *x, int *ldx, doublecomplex *y, int
*ldy, double *trigs, int *ifac, double *work, int
*lwork, int *ierr);
void zfftzm_64_ (long *iopt, long *m, long *n, double
*scale, doublecomplex *x, long *ldx, doublecomplex
*y, long *ldy, double *trigs, long *ifac, double
*work, long *lwork, long *ierr);
zfftzm initializes the trigonometric weight and factor
tables or computes the one-dimensional Fast Fourier
Transform (forward or inverse) of a set of data sequences
stored in a two-dimensional double complex array:
N1-1
Y(k,l) = SUM W*X(j,l)
j=0
where
k ranges from 0 to N1-1 and l ranges from 0 to N2-1
i = sqrt(-1)
isign = 1 for inverse transform or -1 for forward transform
W = exp(isign*i*j*k*2*pi/N1)
IOPT (input)
Integer specifying the operation to be performed:
IOPT = 0 computes the trigonometric weight table
and factor table
IOPT = -1 computes forward FFT
IOPT = +1 computes inverse FFT
N1 (input)
Integer specifying length of the input sequences.
N1 is most efficient when it is a product of small
primes. N1 >= 0. Unchanged on exit.
N2 (input)
Integer specifying number of input sequences. N2
>= 0. Unchanged on exit.
SCALE (input)
Double precision scalar by which transform results
are scaled. Unchanged on exit. SCALE is
defaulted to 1.0D0 for F95 INTERFACE.
X (input) X is a double complex array of dimensions (LDX,
N2) that contains the sequences to be transformed
stored in its columns.
LDX (input)
Leading dimension of X. LDX >= N1 Unchanged on
exit.
Y (output)
Y is a double complex array of dimensions (LDY,
N2) that contains the transform results of the
input sequences. X and Y can be the same array
starting at the same memory location, in which
case the input sequences are overwritten by their
transform results. Otherwise, it is assumed that
there is no overlap between X and Y in memory.
LDY (input)
Leading dimension of Y. If X and Y are the same
array, LDY = LDX Else LDY >= N1 Unchanged on exit.
TRIGS (input/output)
Double precision array of length 2*N1 that con-
tains the trigonometric weights. The weights are
computed when the routine is called with IOPT = 0
and they are used in subsequent calls when IOPT =
1 or IOPT = -1. Unchanged on exit.
IFAC (input/output)
Integer array of dimension at least 128 that con-
tains the factors of N1. The factors are computed
when the routine is called with IOPT = 0 and they
are used in subsequent calls when IOPT = 1 or IOPT
= -1. Unchanged on exit.
WORK (workspace)
Double precision array of dimension at least
2*N1*NCPUS where NCPUS is the number of threads
used to execute the routine. The user can also
choose to have the routine allocate its own
workspace (see LWORK).
LWORK (input)
Integer specifying workspace size. If LWORK = 0,
the routine will allocate its own workspace.
IERR (output)
On exit, integer IERR has one of the following
values:
0 = normal return
-1 = IOPT is not 0, 1 or -1
-2 = N1 < 0
-3 = N2 < 0
-4 = (LDX < N1)
-5 = (LDY < N1) or (LDY not equal LDX when X and Y
are same array)
-6 = (LWORK not equal 0) and (LWORK < 2*N1*NCPUS)
-7 = memory allocation failed
fft