cfftb (3p)

Name

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

Synopsis

SUBROUTINE CFFTB(N, X, WSAVE)

COMPLEX X(*)
INTEGER N
REAL WSAVE(*)

SUBROUTINE CFFTB_64(N, X, WSAVE)

COMPLEX X(*)
INTEGER*8 N
REAL WSAVE(*)




F95 INTERFACE
SUBROUTINE FFTB(N, X, WSAVE)

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

SUBROUTINE FFTB_64(N, X, WSAVE)

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




C INTERFACE
#include <sunperf.h>

void cfftb(int n, complex *x, float *wsave);

void cfftb_64(long n, complex *x, float *wsave);

Description

Oracle Solaris Studio Performance Library                            cfftb(3P)



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


SYNOPSIS
       SUBROUTINE CFFTB(N, X, WSAVE)

       COMPLEX X(*)
       INTEGER N
       REAL WSAVE(*)

       SUBROUTINE CFFTB_64(N, X, WSAVE)

       COMPLEX X(*)
       INTEGER*8 N
       REAL WSAVE(*)




   F95 INTERFACE
       SUBROUTINE FFTB(N, X, WSAVE)

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

       SUBROUTINE FFTB_64(N, X, WSAVE)

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




   C INTERFACE
       #include <sunperf.h>

       void cfftb(int n, complex *x, float *wsave);

       void cfftb_64(long n, complex *x, float *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 CFFTI.




                                  7 Nov 2015                         cfftb(3P)