Contents
dfft2i - initialize the array WSAVE, which is used in both
the forward and backward transforms.
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);
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 initialize array WORK before calling
DFFT2F and/or DFFT2B if M, N and WORK 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.