vdcosqi - initialize the array WSAVE, which is used in both VCOSQF and
VCOSQB.
SUBROUTINE VDCOSQI( N, WSAVE)
INTEGER N
DOUBLE PRECISION WSAVE(*)
SUBROUTINE VDCOSQI_64( N, WSAVE)
INTEGER*8 N
DOUBLE PRECISION WSAVE(*)
SUBROUTINE VCOSQI( N, WSAVE)
INTEGER :: N
REAL(8), DIMENSION(:) :: WSAVE
SUBROUTINE VCOSQI_64( N, WSAVE)
INTEGER(8) :: N
REAL(8), DIMENSION(:) :: WSAVE
#include <sunperf.h>
void vdcosqi(int n, double *wsave);
void vdcosqi_64(long n, double *wsave);
- N (input)
Length of the sequence to be transformed. The method is most efficient when N is a product of small
primes.
- WSAVE (input/output)
On entry, an array of dimension (2 * N + 15) or greater. VDCOSQI needs to be
called only once to initialize WSAVE before calling VDCOSQF and/or VDCOSQB if N
and WSAVE remain unchanged between these calls. Thus, subsequent transforms or
inverse transforms of same size can be obtained faster than the first since
they do not require initialization of the workspace.