dezftf(3P) Sun Performance Library dezftf(3P)NAMEdezftf - computes the Fourier coefficients of a periodic sequence.
DEZFTF is a simplified but slower version of DFFTF.
SYNOPSIS
SUBROUTINE DEZFTF(N, R, AZERO, A, B, WSAVE)
INTEGER N
DOUBLE PRECISION AZERO
DOUBLE PRECISION R(*), A(*), B(*), WSAVE(*)
SUBROUTINE DEZFTF_64(N, R, AZERO, A, B, WSAVE)
INTEGER*8 N
DOUBLE PRECISION AZERO
DOUBLE PRECISION R(*), A(*), B(*), WSAVE(*)
F95 INTERFACE
SUBROUTINE DEZFTF(N, R, AZERO, A, B, WSAVE)
INTEGER :: N
REAL(8) :: AZERO
REAL(8), DIMENSION(:) :: R, A, B, WSAVE
SUBROUTINE DEZFTF_64(N, R, AZERO, A, B, WSAVE)
INTEGER(8) :: N
REAL(8) :: AZERO
REAL(8), DIMENSION(:) :: R, A, B, WSAVE
C INTERFACE
#include <sunperf.h>
void dezftf(int n, double *r, double *azero, double *a, double *b, dou‐
ble *wsave);
void dezftf_64(long n, double *r, double *azero, double *a, double *b,
double *wsave);
ARGUMENTS
N (input) Length of the sequence to be transformed. The method is most
efficient when N is the product of small primes. N >= 0.
R (input) On entry, a real array of length N containing the sequence to
be transformed. On exit, R is unchanged.
AZERO (output)
On exit, the sum from i=1 to i=n of r(i)/n.
A (output)
On exit, arrays that contain the remaining Fourier coeffi‐
cients.
B (output)
On exit, arrays that contain the remaining Fourier coeffi‐
cients.
WSAVE (input)
On entry, an array with dimension of at least (3 * N + 15),
initialized by DEZFTI.
6 Mar 2009 dezftf(3P)
