cfft2b(3P) Sun Performance Library cfft2b(3P)NAMEcfft2b - compute a periodic sequence from its Fourier coefficients.
The xFFT operations are unnormalized, so a call of xFFT2F followed by a
call of xFFT2B will multiply the input sequence by M*N.
SYNOPSIS
SUBROUTINE CFFT2B(M, N, A, LDA, WORK, LWORK)
COMPLEX A(LDA,*)
INTEGER M, N, LDA, LWORK
REAL WORK(*)
SUBROUTINE CFFT2B_64(M, N, A, LDA, WORK, LWORK)
COMPLEX A(LDA,*)
INTEGER*8 M, N, LDA, LWORK
REAL WORK(*)
F95 INTERFACE
SUBROUTINE FFT2B([M], [N], A, [LDA], WORK, LWORK)
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: M, N, LDA, LWORK
REAL, DIMENSION(:) :: WORK
SUBROUTINE FFT2B_64([M], [N], A, [LDA], WORK, LWORK)
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: M, N, LDA, LWORK
REAL, DIMENSION(:) :: WORK
C INTERFACE
#include <sunperf.h>
void cfft2b(int m, int n, complex *a, int lda, float *work, int lwork);
void cfft2b_64(long m, long n, complex *a, long lda, float *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 input, workspace WORK must have been initialized by
CFFT2I.
LWORK (input)
The dimension of the array WORK. LWORK >= (4 * (M + N) + 30)
6 Mar 2009 cfft2b(3P)