vcfftf(3P) Sun Performance Library vcfftf(3P)NAMEvcfftf - compute the Fourier coefficients of a periodic sequence. The
VCFFT operations are normalized, so a call of VCFFTF followed by a call
of VCFFTB will return the original sequence.
SYNOPSIS
SUBROUTINE VCFFTF(M, N, X, XT, MDIMX, ROWCOL, WSAVE)
CHARACTER * 1 ROWCOL
COMPLEX X(MDIMX,*), XT(MDIMX,*), WSAVE(*)
INTEGER M, N, MDIMX
SUBROUTINE VCFFTF_64(M, N, X, XT, MDIMX, ROWCOL, WSAVE)
CHARACTER * 1 ROWCOL
COMPLEX X(MDIMX,*), XT(MDIMX,*), WSAVE(*)
INTEGER*8 M, N, MDIMX
F95 INTERFACE
SUBROUTINE FFTF([M], [N], X, XT, [MDIMX], ROWCOL, WSAVE)
CHARACTER(LEN=1) :: ROWCOL
COMPLEX, DIMENSION(:) :: WSAVE
COMPLEX, DIMENSION(:,:) :: X, XT
INTEGER :: M, N, MDIMX
SUBROUTINE FFTF_64([M], [N], X, XT, [MDIMX], ROWCOL, WSAVE)
CHARACTER(LEN=1) :: ROWCOL
COMPLEX, DIMENSION(:) :: WSAVE
COMPLEX, DIMENSION(:,:) :: X, XT
INTEGER(8) :: M, N, MDIMX
C INTERFACE
#include <sunperf.h>
void vcfftf(int m, int n, complex *x, complex *xt, int mdimx, char row‐
col, complex *wsave);
void vcfftf_64(long m, long n, complex *x, complex *xt, long mdimx,
char rowcol, complex *wsave);
ARGUMENTS
M (input) If ROWCOL = 'R' or 'r', M is the number of sequences to be
transformed. Otherwise, M is the length of the sequences to
be transformed. M >= 0.
N (input) If ROWCOL = 'R' or 'r', N is the length of the sequences to
be transformed. Otherwise, N is the number of sequences to
be transformed. N >= 0.
X (input/output)
On entry, if ROWCOL = 'R' or 'r' X(MDIMX,N) is an array whose
first M rows contain the sequences to be transformed. Other‐
wise, X(MDIMX,N) contains data sequences of length M stored
in N columns of X.
XT (workspace)
A work array. The size of this workspace depends on the num‐
ber of threads that are used to execute this routine. There
are various functions that can be used to determine the num‐
ber of threads available (get_env, available_threads, etc).
The appropriate amount, which is (number of threads * length
of data sequences), can then be dynamically allocated for XT
from the driver routine. If XT can only be allocated stati‐
cally, then the size of XT should be (length of data
sequences * number of sequences).
MDIMX (input)
Leading dimension of the arrays X and XT as specified in a
dimension or type statement. MDIMX >= M.
ROWCOL (input)
Indicates whether data sequences in X are stored row-wise
('R' or 'r') or column-wise ('C' or 'c').
WSAVE (input)
On entry, an array of dimension (K+15) or greater, where K =
M if ROWCOL = ('R' or 'r'). Otherwise, K = N. WSAVE is ini‐
tialized by VCFFTI.
6 Mar 2009 vcfftf(3P)
