rfftb
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);
-
* 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)
-
On entry, an array of length N containing the sequence to be
transformed.
-
* WSAVE (input)
-
On entry, WSAVE must be an array of dimension (2 * N + 15) or greater and
must have been initialized by RFFTI.