Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / tsa-4.2.4 / poly2ar.m

diff --git a/octave_packages/tsa-4.2.4/poly2ar.m b/octave_packages/tsa-4.2.4/poly2ar.m
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+++ b/octave_packages/tsa-4.2.4/poly2ar.m
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+function [A] = poly2ar(A);
+% Converts AR polymials into autoregressive parameters. 
+% Multiple polynomials can be converted. 
+%
+% function  [AR] = poly2ar(A);
+%
+%  INPUT:
+% A     AR polynomial, each row represents one polynomial
+%
+%  OUTPUT
+% AR    autoregressive model parameter 
+%
+% see also ACOVF ACORF DURLEV RC2AR AR2POLY
+
+%       $Id: poly2ar.m 5090 2008-06-05 08:12:04Z schloegl $
+%       Copyright (C) 1998-2002,2008 by Alois Schloegl <a.schloegl@ieee.org>
+%
+%    This program is free software: you can redistribute it and/or modify
+%    it under the terms of the GNU General Public License as published by
+%    the Free Software Foundation, either version 3 of the License, or
+%    (at your option) any later version.
+%
+%    This program is distributed in the hope that it will be useful,
+%    but WITHOUT ANY WARRANTY; without even the implied warranty of
+%    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%    GNU General Public License for more details.
+%
+%    You should have received a copy of the GNU General Public License
+%    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+% Inititialization
+[lr,lc]=size(A);
+
+if ~all(A(:,1)==1)
+       fprintf(2,'Warning POLY2AR: input argument might not be an AR-polynom');
+end;   
+
+A = -A(:,2:size(A,2))./A(:,ones(1,size(A,2)-1));