Contents
rffti - initialize the array WSAVE, which is used in both
RFFTF and RFFTB.
SUBROUTINE RFFTI(N, WSAVE)
INTEGER N
REAL WSAVE(*)
SUBROUTINE RFFTI_64(N, WSAVE)
INTEGER*8 N
REAL WSAVE(*)
F95 INTERFACE
SUBROUTINE FFTI(N, WSAVE)
INTEGER :: N
REAL, DIMENSION(:) :: WSAVE
SUBROUTINE FFTI_64(N, WSAVE)
INTEGER(8) :: N
REAL, DIMENSION(:) :: WSAVE
C INTERFACE
#include <sunperf.h>
void rffti(int n, float *wsave);
void rffti_64(long n, float *wsave);
N (input) Length of the sequence to be transformed. N >= 0.
WSAVE (input)
On entry, an array of dimension (2 * N + 15) or
greater. RFFTI needs to be called only once to
initialize array WORK before calling RFFTF and/or
RFFTB if N and WSAVE remain unchanged between
these calls. Thus, subsequent transforms or
inverse transforms of same size can be obtained
faster than the first since they do not require
initialization of the workspace.