zfft2b
zfft2b - 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.
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(*)
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
#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);
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* M (input)
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Number of rows to be transformed. These subroutines are most efficient when M is a product of small primes. M >= 0.
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* N (input)
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Number of columns to be transformed. These subroutines are most efficient when N is a product of small primes. N >= 0.
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* A (input/output)
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On entry, a two-dimensional array A(M,N) that contains the sequences to be transformed.
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* LDA (input)
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Leading dimension of the array containing the data to be transformed. LDA >= M.
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* WORK (input)
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On entry, an array with dimension of at least LWORK. WORK must have been initialized by ZFFT2I.
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* LWORK (input)
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The dimension of the array WORK. LWORK >= (4 * (M + N) + 30)