vdfftb (3p)

Name

vdfftb - compute a periodic sequence from its Fourier coefficients. The VDFFT operations are normalized, so a call of VDFFTF followed by a call of VDFFTB will return the original sequence.

Synopsis

SUBROUTINE VDFFTB(M, N, X, XT, MDIMX, WSAVE)

INTEGER M, N, MDIMX
DOUBLE PRECISION X(MDIMX,*), XT(MDIMX,*), WSAVE(*)

SUBROUTINE VDFFTB_64(M, N, X, XT, MDIMX, WSAVE)

INTEGER*8 M, N, MDIMX
DOUBLE PRECISION X(MDIMX,*), XT(MDIMX,*), WSAVE(*)




F95 INTERFACE
SUBROUTINE FFTB(M, N, X, XT, MDIMX, WSAVE)

INTEGER :: M, N, MDIMX
REAL(8), DIMENSION(:) :: WSAVE
REAL(8), DIMENSION(:,:) :: X, XT

SUBROUTINE FFTB_64(M, N, X, XT, MDIMX, WSAVE)

INTEGER(8) :: M, N, MDIMX
REAL(8), DIMENSION(:) :: WSAVE
REAL(8), DIMENSION(:,:) :: X, XT




C INTERFACE
#include <sunperf.h>

void  vdfftb(int  m,  int  n,  double *x, double *xt, int mdimx, double
*wsave);

void vdfftb_64(long m, long n, double *x, double *xt, long mdimx,  dou-
ble *wsave);

Description

Oracle Solaris Studio Performance Library                           vdfftb(3P)



NAME
       vdfftb  -  compute  a  periodic sequence from its Fourier coefficients.
       The VDFFT operations are normalized, so a call of VDFFTF followed by  a
       call of VDFFTB will return the original sequence.


SYNOPSIS
       SUBROUTINE VDFFTB(M, N, X, XT, MDIMX, WSAVE)

       INTEGER M, N, MDIMX
       DOUBLE PRECISION X(MDIMX,*), XT(MDIMX,*), WSAVE(*)

       SUBROUTINE VDFFTB_64(M, N, X, XT, MDIMX, WSAVE)

       INTEGER*8 M, N, MDIMX
       DOUBLE PRECISION X(MDIMX,*), XT(MDIMX,*), WSAVE(*)




   F95 INTERFACE
       SUBROUTINE FFTB(M, N, X, XT, MDIMX, WSAVE)

       INTEGER :: M, N, MDIMX
       REAL(8), DIMENSION(:) :: WSAVE
       REAL(8), DIMENSION(:,:) :: X, XT

       SUBROUTINE FFTB_64(M, N, X, XT, MDIMX, WSAVE)

       INTEGER(8) :: M, N, MDIMX
       REAL(8), DIMENSION(:) :: WSAVE
       REAL(8), DIMENSION(:,:) :: X, XT




   C INTERFACE
       #include <sunperf.h>

       void  vdfftb(int  m,  int  n,  double *x, double *xt, int mdimx, double
                 *wsave);

       void vdfftb_64(long m, long n, double *x, double *xt, long mdimx,  dou-
                 ble *wsave);



ARGUMENTS
       M (input) The number of sequences to be transformed.  M >= 0.


       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.  For VDFFTF, a real two-dimensional array X(M,N)
                 whose rows contain the sequences to be transformed.


       XT (workspace)
                 A real two-dimensional work array with dimensions of (MDIMX x
                 N).


       MDIMX (input)
                 Leading dimension of the arrays X and XT as  specified  in  a
                 dimension or type statement.  MDIMX >= M.


       WSAVE (input)
                 On entry, an array of dimension (N+15) or greater initialized
                 by VDFFTI.



                                  7 Nov 2015                        vdfftb(3P)