zfft2b(3P) Sun Performance Library zfft2b(3P)NAMEzfft2b - compute a periodic sequence from its Fourier coefficients.
The FFT operations are unnormalized, so a call of ZFFT2F followed by a
call of ZFFT2B will multiply the input sequence by M*N.
SYNOPSIS
SUBROUTINE ZFFT2B(M, N, A, LDA, WORK, LWORK)
DOUBLE COMPLEX A(LDA,*)
INTEGER M, N, LDA, LWORK
DOUBLE PRECISION WORK(*)
SUBROUTINE ZFFT2B_64(M, N, A, LDA, WORK, LWORK)
DOUBLE COMPLEX A(LDA,*)
INTEGER*8 M, N, LDA, LWORK
DOUBLE PRECISION WORK(*)
F95 INTERFACE
SUBROUTINE FFT2B([M], [N], A, [LDA], WORK, LWORK)
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER :: M, N, LDA, LWORK
REAL(8), DIMENSION(:) :: WORK
SUBROUTINE FFT2B_64([M], [N], A, [LDA], WORK, LWORK)
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER(8) :: M, N, LDA, LWORK
REAL(8), DIMENSION(:) :: WORK
C INTERFACE
#include <sunperf.h>
void zfft2b(int m, int n, doublecomplex *a, int lda, double *work, int
lwork);
void zfft2b_64(long m, long n, doublecomplex *a, long lda, double
*work, long lwork);
ARGUMENTS
M (input) Number of rows to be transformed. These subroutines are most
efficient when M is a product of small primes. M >= 0.
N (input) Number of columns to be transformed. These subroutines are
most efficient when N is a product of small primes. N >= 0.
A (input/output)
On entry, a two-dimensional array A(M,N) that contains the
sequences to be transformed.
LDA (input)
Leading dimension of the array containing the data to be
transformed. LDA >= M.
WORK (input)
On entry, an array with dimension of at least LWORK. WORK
must have been initialized by ZFFT2I.
LWORK (input)
The dimension of the array WORK. LWORK >= (4 * (M + N) + 30)
6 Mar 2009 zfft2b(3P)