zfftb (3p)

Name

zfftb - compute a periodic sequence from its Fourier coefficients. The FFT operations are unnormalized, so a call of ZFFTF followed by a call of ZFFTB will multiply the input sequence by N.

Synopsis

SUBROUTINE ZFFTB(N, X, WSAVE)

DOUBLE COMPLEX X(*)
INTEGER N
DOUBLE PRECISION WSAVE(*)

SUBROUTINE ZFFTB_64(N, X, WSAVE)

DOUBLE COMPLEX X(*)
INTEGER*8 N
DOUBLE PRECISION WSAVE(*)




F95 INTERFACE
SUBROUTINE FFTB(N, X, WSAVE)

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

SUBROUTINE FFTB_64(N, X, WSAVE)

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




C INTERFACE
#include <sunperf.h>

void zfftb(int n, doublecomplex *x, double *wsave);

void zfftb_64(long n, doublecomplex *x, double *wsave);

Description

Oracle Solaris Studio Performance Library                            zfftb(3P)



NAME
       zfftb - compute a periodic sequence from its Fourier coefficients.  The
       FFT operations are unnormalized, so a call of ZFFTF followed by a  call
       of ZFFTB will multiply the input sequence by N.


SYNOPSIS
       SUBROUTINE ZFFTB(N, X, WSAVE)

       DOUBLE COMPLEX X(*)
       INTEGER N
       DOUBLE PRECISION WSAVE(*)

       SUBROUTINE ZFFTB_64(N, X, WSAVE)

       DOUBLE COMPLEX X(*)
       INTEGER*8 N
       DOUBLE PRECISION WSAVE(*)




   F95 INTERFACE
       SUBROUTINE FFTB(N, X, WSAVE)

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

       SUBROUTINE FFTB_64(N, X, WSAVE)

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




   C INTERFACE
       #include <sunperf.h>

       void zfftb(int n, doublecomplex *x, double *wsave);

       void zfftb_64(long n, doublecomplex *x, double *wsave);



ARGUMENTS
       N (input) Length  of the sequence to be transformed.  These subroutines
                 are most efficient when N is a product of small primes.  N >=
                 0.


       X (input/output)
                 On  entry, an array of length N containing the sequence to be
                 transformed.


       WSAVE (input/output)
                 On entry, WSAVE must be an array of dimension (4 * N + 15) or
                 greater and must have been initialized by ZFFTI.



                                  7 Nov 2015                         zfftb(3P)