dcosqf(3P) Sun Performance Library dcosqf(3P)NAMEdcosqf - compute the Fourier coefficients in a cosine series represen‐
tation with only odd wave numbers. The COSQ operations are unnormal‐
ized inverses of themselves, so a call to COSQF followed by a call to
COSQB will multiply the input sequence by 4 * N.
SYNOPSIS
SUBROUTINE DCOSQF(N, X, WSAVE)
INTEGER N
DOUBLE PRECISION X(*), WSAVE(*)
SUBROUTINE DCOSQF_64(N, X, WSAVE)
INTEGER*8 N
DOUBLE PRECISION X(*), WSAVE(*)
F95 INTERFACE
SUBROUTINE COSQF([N], X, WSAVE)
INTEGER :: N
REAL(8), DIMENSION(:) :: X, WSAVE
SUBROUTINE COSQF_64([N], X, WSAVE)
INTEGER(8) :: N
REAL(8), DIMENSION(:) :: X, WSAVE
C INTERFACE
#include <sunperf.h>
void dcosqf(int n, double *x, double *wsave);
void dcosqf_64(long n, double *x, double *wsave);
ARGUMENTS
N (input) Length of the sequence to be transformed. These subroutines
are most efficient when N is a product of small primes. N >=
0.
X (input/output)
On entry, an array of length N containing the sequence to be
transformed. On exit, the quarter-wave cosine transform of
the input.
WSAVE (input)
On entry, an array with dimension of at least (3 * N + 15)
that has been initialized by DCOSQI.
6 Mar 2009 dcosqf(3P)
