NAME

rffti - initialize the array WSAVE, which is used in both RFFTF and RFFTB.

SYNOPSIS

  SUBROUTINE RFFTI( N, WSAVE)
  INTEGER N
  REAL WSAVE(*)

  SUBROUTINE RFFTI_64( N, WSAVE)
  INTEGER*8 N
  REAL WSAVE(*)

  SUBROUTINE FFTI( N, WSAVE)
  INTEGER :: N
  REAL, DIMENSION(:) :: WSAVE

  SUBROUTINE FFTI_64( N, WSAVE)
  INTEGER(8) :: N
  REAL, DIMENSION(:) :: WSAVE

#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/output)
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.