dcost - compute the discrete Fourier cosine transform of an even sequence. The COST transforms are unnormalized inverses of themselves, so a call of COST followed by another call of COST will multiply the input sequence by 2 * (N-1).
SUBROUTINE DCOST(N, X, WSAVE) INTEGER N DOUBLE PRECISION X(*), WSAVE(*) SUBROUTINE DCOST_64(N, X, WSAVE) INTEGER*8 N DOUBLE PRECISION X(*), WSAVE(*) F95 INTERFACE SUBROUTINE COST(N, X, WSAVE) INTEGER :: N REAL(8), DIMENSION(:) :: X, WSAVE SUBROUTINE COST_64(N, X, WSAVE) INTEGER(8) :: N REAL(8), DIMENSION(:) :: X, WSAVE C INTERFACE #include <sunperf.h> void dcost(int n, double *x, double *wsave); void dcost_64(long n, double *x, double *wsave);
Oracle Solaris Studio Performance Library dcost(3P) NAME dcost - compute the discrete Fourier cosine transform of an even sequence. The COST transforms are unnormalized inverses of themselves, so a call of COST followed by another call of COST will multiply the input sequence by 2 * (N-1). SYNOPSIS SUBROUTINE DCOST(N, X, WSAVE) INTEGER N DOUBLE PRECISION X(*), WSAVE(*) SUBROUTINE DCOST_64(N, X, WSAVE) INTEGER*8 N DOUBLE PRECISION X(*), WSAVE(*) F95 INTERFACE SUBROUTINE COST(N, X, WSAVE) INTEGER :: N REAL(8), DIMENSION(:) :: X, WSAVE SUBROUTINE COST_64(N, X, WSAVE) INTEGER(8) :: N REAL(8), DIMENSION(:) :: X, WSAVE C INTERFACE #include <sunperf.h> void dcost(int n, double *x, double *wsave); void dcost_64(long n, double *x, double *wsave); ARGUMENTS N (input) Length of the sequence to be transformed. These subroutines are most efficient when N - 1 is a product of small primes. N >= 2. X (input/output) On entry, an array of length N containing the sequence to be transformed. On exit, the cosine transform of the input. WSAVE (input) On entry, an array with dimension of at least (3 * N + 15), initialized by DCOSTI. 7 Nov 2015 dcost(3P)