rfft2b - compute a periodic sequence from its Fourier coefficients. The RFFT operations are unnormalized, so a call of RFFT2F followed by a call of RFFT2B will multiply the input sequence by M*N.
SUBROUTINE RFFT2B(PLACE, M, N, A, LDA, B, LDB, WORK, LWORK) CHARACTER*1 PLACE INTEGER M, N, LDA, LDB, LWORK REAL A(LDA,*), B(2*LDB,*), WORK(*) SUBROUTINE RFFT2B_64(PLACE, M, N, A, LDA, B, LDB, WORK, LWORK) CHARACTER*1 PLACE INTEGER*8 M, N, LDA, LDB, LWORK REAL A(LDA,*), B(2*LDB,*), WORK(*) F95 INTERFACE SUBROUTINE FFT2B(PLACE, M, N, A, LDA, B, LDB, WORK, LWORK) CHARACTER(LEN=1) :: PLACE INTEGER :: M, N, LDA, LDB, LWORK REAL, DIMENSION(:) :: WORK REAL, DIMENSION(:,:) :: A, B SUBROUTINE FFT2B_64(PLACE, M, N, A, LDA, B, LDB, WORK, LWORK) CHARACTER(LEN=1) :: PLACE INTEGER(8) :: M, N, LDA, LDB, LWORK REAL, DIMENSION(:) :: WORK REAL, DIMENSION(:,:) :: A, B C INTERFACE #include <sunperf.h> void rfft2b(char place, int m, int n, float *a, int lda, float *b, int ldb, float *work, int lwork); void rfft2b_64(char place, long m, long n, float *a, long lda, float *b, long ldb, float *work, long lwork);
Oracle Solaris Studio Performance Library rfft2b(3P) NAME rfft2b - compute a periodic sequence from its Fourier coefficients. The RFFT operations are unnormalized, so a call of RFFT2F followed by a call of RFFT2B will multiply the input sequence by M*N. SYNOPSIS SUBROUTINE RFFT2B(PLACE, M, N, A, LDA, B, LDB, WORK, LWORK) CHARACTER*1 PLACE INTEGER M, N, LDA, LDB, LWORK REAL A(LDA,*), B(2*LDB,*), WORK(*) SUBROUTINE RFFT2B_64(PLACE, M, N, A, LDA, B, LDB, WORK, LWORK) CHARACTER*1 PLACE INTEGER*8 M, N, LDA, LDB, LWORK REAL A(LDA,*), B(2*LDB,*), WORK(*) F95 INTERFACE SUBROUTINE FFT2B(PLACE, M, N, A, LDA, B, LDB, WORK, LWORK) CHARACTER(LEN=1) :: PLACE INTEGER :: M, N, LDA, LDB, LWORK REAL, DIMENSION(:) :: WORK REAL, DIMENSION(:,:) :: A, B SUBROUTINE FFT2B_64(PLACE, M, N, A, LDA, B, LDB, WORK, LWORK) CHARACTER(LEN=1) :: PLACE INTEGER(8) :: M, N, LDA, LDB, LWORK REAL, DIMENSION(:) :: WORK REAL, DIMENSION(:,:) :: A, B C INTERFACE #include <sunperf.h> void rfft2b(char place, int m, int n, float *a, int lda, float *b, int ldb, float *work, int lwork); void rfft2b_64(char place, long m, long n, float *a, long lda, float *b, long ldb, float *work, long lwork); ARGUMENTS PLACE (input) Character. If PLACE = 'I' or 'i' (for in-place) , the input and output data are stored in array A. If PLACE = 'O' or 'o' (for out-of-place), the input data is stored in array B while the output is stored in A. M (input) Integer specifying the number of rows to be transformed. It is most efficient when M is a product of small primes. M >= 0; when M = 0, the subroutine returns immediately without changing any data. N (input) Integer specifying the number of columns to be transformed. It is most most efficient when N is a product of small primes. N >= 0; when N = 0, the subroutine returns immedi- ately without changing any data. A (input/output) Real array of dimension (LDA,N). On entry, the two-dimen- sional array A(LDA,N) contains the input data to be trans- formed if an in-place transform is requested. Otherwise, it is not referenced. Upon exit, results are stored in A(1:M,1:N). LDA (input) Integer specifying the leading dimension of A. If an out-of- place transform is desired LDA >= M. Else if an in-place transform is desired LDA >= 2*(M/2+1) and LDA must be even. B (input/output) Real array of dimension (2*LDB, N). On entry, if an out-of- place transform is requested B contains the input data. Oth- erwise, B is not referenced. B is unchanged upon exit. LDB (input) Integer. If an out-of-place transform is desired, 2*LDB is the leading dimension of the array B which contains the data to be transformed and 2*LDB >= 2*(M/2+1). Otherwise it is not referenced. WORK (input/output) One-dimensional real array of length at least LWORK. On input, WORK must have been initialized by RFFT2I. LWORK (input) Integer. LWORK >= (M + 2*N + MAX(M, 2*N) + 30) 7 Nov 2015 rfft2b(3P)