vcffti

NAME

vcffti - initialize the array WSAVE, which is used in both VCFFTF and VCFFTB.

SYNOPSIS

  SUBROUTINE VCFFTI( N, WSAVE)
  COMPLEX WSAVE(*)
  INTEGER N
 
  SUBROUTINE VCFFTI_64( N, WSAVE)
  COMPLEX WSAVE(*)
  INTEGER*8 N

F95 INTERFACE

  SUBROUTINE VFFTI( N, WSAVE)
  COMPLEX, DIMENSION(:) :: WSAVE
  INTEGER :: N
 
  SUBROUTINE VFFTI_64( N, WSAVE)
  COMPLEX, DIMENSION(:) :: WSAVE
  INTEGER(8) :: N

C INTERFACE

#include <sunperf.h>

void vcffti(int n, complex *wsave);

void vcffti_64(long n, complex *wsave);

ARGUMENTS

* N (input): Length of the sequence to be transformed. N >= 0.
* WSAVE (input): On entry, an array of dimension (2*N + 15) or greater. VCFFTI needs to be called only once to initialize WSAVE before calling VCFFTF and/or VCFFTB 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.