--- /dev/null
+function [A,E] = ac2poly(acf);
+% converts the autocorrelation sequence into an AR polynomial
+% [A,Efinal] = ac2poly(r)
+%
+% see also ACOVF ACORF AR2RC RC2AR DURLEV AC2POLY, POLY2RC, RC2POLY, RC2AC, AC2RC, POLY2AC
+%
+
+% $Id: ac2poly.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/>.
+
+
+if all(size(acf))>1,
+ fprintf(2,'Error AC2POLY: "r" must be a vector\n');
+ return;
+end;
+
+
+mfilename='AC2POLY';
+if ~exist('durlev','file')
+ fprintf(2,'Error %s: DURLEV.M not found. \n Download TSA toolbox from http://www.dpmi.tu-graz.ac.at/~schloegl/matlab/tsa/\n',mfilename);
+ return;
+end;
+
+[AR,RC,PE] = durlev(acf);
+
+A = [ones(size(AR,1),1),-AR];
+E = PE(:,size(PE,2));