Contents

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

NAME

     zffti - initialize the array WSAVE, which is  used  in  both
     ZFFTF and ZFFTB.

SYNOPSIS

     SUBROUTINE ZFFTI(N, WSAVE)

     INTEGER N
     DOUBLE PRECISION WSAVE(*)

     SUBROUTINE ZFFTI_64(N, WSAVE)

     INTEGER*8 N
     DOUBLE PRECISION WSAVE(*)

  F95 INTERFACE
     SUBROUTINE ZFFTI(N, WSAVE)

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

     SUBROUTINE ZFFTI_64(N, WSAVE)

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

  C INTERFACE
     #include <sunperf.h>

     void zffti(int n, double *wsave);

     void zffti_64(long n, double *wsave);

ARGUMENTS

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

     WSAVE (input/output)
               On entry, an array of dimension (4 * N  +  15)  or
               greater.   ZFFTI  needs  to be called only once to
               initialize array WORK before calling ZFFTF  and/or
               ZFFTB  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.