dffti (3p)

Name

dffti - initialize the array WSAVE, which is used in both DFFTF and DFFTB.

Synopsis

SUBROUTINE DFFTI(N, WSAVE)

INTEGER N
DOUBLE PRECISION WSAVE(*)

SUBROUTINE DFFTI_64(N, WSAVE)

INTEGER*8 N
DOUBLE PRECISION WSAVE(*)




F95 INTERFACE
SUBROUTINE FFTI(N, WSAVE)

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

SUBROUTINE FFTI_64(N, WSAVE)

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




C INTERFACE
#include <sunperf.h>

void dffti(int n, double *wsave);

void dffti_64(long n, double *wsave);

Description

Oracle Solaris Studio Performance Library                            dffti(3P)



NAME
       dffti  -  initialize  the  array WSAVE, which is used in both DFFTF and
       DFFTB.


SYNOPSIS
       SUBROUTINE DFFTI(N, WSAVE)

       INTEGER N
       DOUBLE PRECISION WSAVE(*)

       SUBROUTINE DFFTI_64(N, WSAVE)

       INTEGER*8 N
       DOUBLE PRECISION WSAVE(*)




   F95 INTERFACE
       SUBROUTINE FFTI(N, WSAVE)

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

       SUBROUTINE FFTI_64(N, WSAVE)

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




   C INTERFACE
       #include <sunperf.h>

       void dffti(int n, double *wsave);

       void dffti_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 (2 *  N  +  15)  or  greater.
                 DFFTI  needs  to be called only once to initialize array WORK
                 before calling DFFTF and/or  DFFTB  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.




                                  7 Nov 2015                         dffti(3P)