Contents

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

NAME

     vzffti - initialize the array WSAVE, which is used  in  both
     VZFFTF and VZFFTB.

SYNOPSIS

     SUBROUTINE VZFFTI(N, WSAVE)

     DOUBLE COMPLEX WSAVE(*)
     INTEGER N

     SUBROUTINE VZFFTI_64(N, WSAVE)

     DOUBLE COMPLEX WSAVE(*)
     INTEGER*8 N

  F95 INTERFACE
     SUBROUTINE VFFTI(N, WSAVE)

     COMPLEX(8), DIMENSION(:) :: WSAVE
     INTEGER :: N

     SUBROUTINE VFFTI_64(N, WSAVE)

     COMPLEX(8), DIMENSION(:) :: WSAVE
     INTEGER(8) :: N

  C INTERFACE
     #include <sunperf.h>

     void vzffti(int n, doublecomplex *wsave);

     void vzffti_64(long n, doublecomplex *wsave);

ARGUMENTS

     N (input) Length of the sequence to be transformed.  N >= 0.

     WSAVE (input)
               On entry, an  array  of  dimension  (N  +  15)  or
               greater.   VZFFTI  needs to be called only once to
               initialize  WSAVE  before  calling  VZFFTF  and/or
               VZFFTB  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.