dfft2i(3P) Sun Performance Library dfft2i(3P)NAMEdfft2i - initialize the array WSAVE, which is used in both the forward
and backward transforms.
SYNOPSIS
SUBROUTINE DFFT2I(M, N, WORK)
INTEGER M, N
DOUBLE PRECISION WORK(*)
SUBROUTINE DFFT2I_64(M, N, WORK)
INTEGER*8 M, N
DOUBLE PRECISION WORK(*)
F95 INTERFACE
SUBROUTINE FFT2I(M, N, WORK)
INTEGER :: M, N
REAL(8), DIMENSION(:) :: WORK
SUBROUTINE FFT2I_64(M, N, WORK)
INTEGER(8) :: M, N
REAL(8), DIMENSION(:) :: WORK
C INTERFACE
#include <sunperf.h>
void dfft2i(int m, int n, double *work);
void dfft2i_64(long m, long n, double *work);
ARGUMENTS
M (input) Number of rows to be transformed. M >= 0.
N (input) Number of columns to be transformed. N >= 0.
WORK (input/output)
On entry, an array of dimension (M + 2*N + MAX(M, 2*N) + 30)
or greater. DFFT2I needs to be called only once to initial‐
ize array WORK before calling DFFT2F and/or DFFT2B if M, N
and WORK remain unchanged between these calls. Thus, subse‐
quent transforms or inverse transforms of same size can be
obtained faster than the first since they do not require ini‐
tialization of the workspace.
6 Mar 2009 dfft2i(3P)
