• NAME
• SYNOPSIS
• F95 INTERFACE
• C INTERFACE
• ARGUMENTS

NAME

dcosqi - initialize the array WSAVE, which is used in both COSQF and COSQB.

SYNOPSIS

  SUBROUTINE DCOSQI( N, WSAVE)
  INTEGER N
  DOUBLE PRECISION WSAVE(*)

  SUBROUTINE DCOSQI_64( N, WSAVE)
  INTEGER*8 N
  DOUBLE PRECISION WSAVE(*)

F95 INTERFACE

  SUBROUTINE COSQI( N, WSAVE)
  INTEGER :: N
  REAL(8), DIMENSION(:) :: WSAVE

  SUBROUTINE COSQI_64( N, WSAVE)
  INTEGER(8) :: N
  REAL(8), DIMENSION(:) :: WSAVE

C INTERFACE

#include <sunperf.h>

void dcosqi(int n, double *wsave);

void dcosqi_64(long n, double *wsave);

ARGUMENTS

• 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 (3 * N + 15) or greater. DCOSQI needs to be called only once to initialize WSAVE before calling DCOSQF and/or DCOSQB 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.