rfftb - compute a periodic sequence from its Fourier coefficients. The RFFT operations are unnormalized, so a call of RFFTF followed by a call of RFFTB will multiply the input sequence by N.
SUBROUTINE RFFTB( N, X, WSAVE) INTEGER N REAL X(*), WSAVE(*)
SUBROUTINE RFFTB_64( N, X, WSAVE) INTEGER*8 N REAL X(*), WSAVE(*)
SUBROUTINE FFTB( [N], X, WSAVE) INTEGER :: N REAL, DIMENSION(:) :: X, WSAVE
SUBROUTINE FFTB_64( [N], X, WSAVE) INTEGER(8) :: N REAL, DIMENSION(:) :: X, WSAVE
#include <sunperf.h>
void rfftb(int n, float *x, float *wsave);
void rfftb_64(long n, float *x, float *wsave);