dcosqb(3P) Sun Performance Library dcosqb(3P)NAMEdcosqb - synthesize a Fourier sequence from its representation in terms
of a cosine series with odd wave numbers. The COSQ operations are
unnormalized inverses of themselves, so a call to COSQF followed by a
call to COSQB will multiply the input sequence by 4 * N.
SYNOPSIS
SUBROUTINE DCOSQB(N, X, WSAVE)
INTEGER N
DOUBLE PRECISION X(*), WSAVE(*)
SUBROUTINE DCOSQB_64(N, X, WSAVE)
INTEGER*8 N
DOUBLE PRECISION X(*), WSAVE(*)
F95 INTERFACE
SUBROUTINE COSQB([N], X, WSAVE)
INTEGER :: N
REAL(8), DIMENSION(:) :: X, WSAVE
SUBROUTINE COSQB_64([N], X, WSAVE)
INTEGER(8) :: N
REAL(8), DIMENSION(:) :: X, WSAVE
C INTERFACE
#include <sunperf.h>
void dcosqb(int n, double *x, double *wsave);
void dcosqb_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 synthesis 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 dcosqb(3P)