vdcost(3P) Sun Performance Library vdcost(3P)NAMEvdcost - compute the discrete Fourier cosine transform of an even
sequence. The VCOST transform is normalized, so a call of VCOST fol‐
lowed by a call of VCOST will return the original sequence.
SYNOPSIS
SUBROUTINE VDCOST(M, N, X, XT, MDIMX, WSAVE)
INTEGER M, N, MDIMX
DOUBLE PRECISION X(MDIMX,*), XT(MDIMX,*), WSAVE(*)
SUBROUTINE VDCOST_64(M, N, X, XT, MDIMX, WSAVE)
INTEGER*8 M, N, MDIMX
DOUBLE PRECISION X(MDIMX,*), XT(MDIMX,*), WSAVE(*)
F95 INTERFACE
SUBROUTINE COST([M], [N], X, XT, [MDIMX], WSAVE)
INTEGER :: M, N, MDIMX
REAL(8), DIMENSION(:) :: WSAVE
REAL(8), DIMENSION(:,:) :: X, XT
SUBROUTINE COST_64([M], [N], X, XT, [MDIMX], WSAVE)
INTEGER(8) :: M, N, MDIMX
REAL(8), DIMENSION(:) :: WSAVE
REAL(8), DIMENSION(:,:) :: X, XT
C INTERFACE
#include <sunperf.h>
void vdcost(int m, int n, double *x, double *xt, int mdimx, double
*wsave);
void vdcost_64(long m, long n, double *x, double *xt, long mdimx, dou‐
ble *wsave);
ARGUMENTS
M (input)
The number of sequences to be transformed. M >= 0.
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. For VCOST, a real two- dimensional array with
dimensions of (MDIMX x (N+1)) whose rows contain the
sequences to be transformed. On exit, the cosine transform
of the input.
XT (input)
A real two-dimensional work array with dimensions of (MDIMX x
(N-1)).
MDIMX (input)
Leading dimension of the arrays X and XT as specified in a
dimension or type statement. MDIMX >= M.
WSAVE (input)
On entry, an array of dimension (2 * N + 15) or greater ini‐
tialized by VDCOSTI.
6 Mar 2009 vdcost(3P)
