1 ## Copyright (C) 1995-2012 Kurt Hornik
3 ## This file is part of Octave.
5 ## Octave is free software; you can redistribute it and/or modify it
6 ## under the terms of the GNU General Public License as published by
7 ## the Free Software Foundation; either version 3 of the License, or (at
8 ## your option) any later version.
10 ## Octave is distributed in the hope that it will be useful, but
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ## General Public License for more details.
15 ## You should have received a copy of the GNU General Public License
16 ## along with Octave; see the file COPYING. If not, see
17 ## <http://www.gnu.org/licenses/>.
20 ## @deftypefn {Function File} {} autoreg_matrix (@var{y}, @var{k})
21 ## Given a time series (vector) @var{y}, return a matrix with ones in the
22 ## first column and the first @var{k} lagged values of @var{y} in the
23 ## other columns. I.e., for @var{t} > @var{k}, @code{[1,
24 ## @var{y}(@var{t}-1), @dots{}, @var{y}(@var{t}-@var{k})]} is the t-th row
25 ## of the result. The resulting matrix may be used as a regressor matrix
26 ## in autoregressions.
29 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
30 ## Description: Design matrix for autoregressions
32 function X = autoreg_matrix (y, k)
39 error ("autoreg_matrix: Y must be a vector");
43 y = reshape (y, T, 1);
46 X(:, j+1) = [(zeros (j, 1)); y(1:T-j)];
58 %! assert (autoreg_matrix(A,K),B);
60 %!error autoreg_matrix()
61 %!error autoreg_matrix(1)
62 %!error autoreg_matrix(ones(4,1),5)