cfft2b
cfft2b - 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.
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(*)
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
#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);
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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 input, workspace WORK must have been initialized by CFFT2I.
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* LWORK (input)
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The dimension of the array WORK. LWORK >= (4 * (M + N) + 30)