Contents
dezftf - computes the Fourier coefficients of a periodic
sequence. DEZFTF is a simplified but slower version of
DFFTF.
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, dou-
ble *b, double *wsave);
void dezftf_64(long n, double *r, double azero, double *a,
double *b, double *wsave);
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 (input/output)
On entry, array that contains the remaining
Fourier coefficients. On exit, these arrays are
unchanged.
B (input/output)
On entry, array that contains the remaining
Fourier coefficients. On exit, these arrays are
unchanged.
WSAVE (input)
On entry, an array with dimension of at least (3 *
N + 15), initialized by DEZFTI.