dfftf - compute the Fourier coefficients of a periodic sequence. The FFT operations are unnormalized, so a call of DFFTF followed by a call of DFFTB will multiply the input sequence by N.
SUBROUTINE DFFTF( N, X, WSAVE) INTEGER N DOUBLE PRECISION X(*), WSAVE(*)
SUBROUTINE DFFTF_64( N, X, WSAVE) INTEGER*8 N DOUBLE PRECISION X(*), WSAVE(*)
SUBROUTINE FFTF( [N], X, WSAVE) INTEGER :: N REAL(8), DIMENSION(:) :: X, WSAVE
SUBROUTINE FFTF_64( [N], X, WSAVE) INTEGER(8) :: N REAL(8), DIMENSION(:) :: X, WSAVE
#include <sunperf.h>
void dfftf(int n, double *x, double *wsave);
void dfftf_64(long n, double *x, double *wsave);