rfftf(3P) Sun Performance Library rfftf(3P)NAMErfftf - compute the Fourier coefficients of a periodic sequence. The
FFT operations are unnormalized, so a call of RFFTF followed by a call
of RFFTB will multiply the input sequence by N.
SYNOPSIS
SUBROUTINE RFFTF(N, X, WSAVE)
INTEGER N
REAL X(*), WSAVE(*)
SUBROUTINE RFFTF_64(N, X, WSAVE)
INTEGER*8 N
REAL X(*), WSAVE(*)
F95 INTERFACE
SUBROUTINE FFTF([N], X, WSAVE)
INTEGER :: N
REAL, DIMENSION(:) :: X, WSAVE
SUBROUTINE FFTF_64([N], X, WSAVE)
INTEGER(8) :: N
REAL, DIMENSION(:) :: X, WSAVE
C INTERFACE
#include <sunperf.h>
void rfftf(int n, float *x, float *wsave);
void rfftf_64(long n, float *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 (2 * N + 15) or
greater and must have been initialized by RFFTI.
6 Mar 2009 rfftf(3P)