function ar=lpcls2ar(ls)
%LPCLS2AR convert line spectrum pair frequencies to ar polynomial AR=(LS)
% input vector elements should be in the range 0 to 0.5


%      Copyright (C) Mike Brookes 1997
%
%      Last modified Tue May 12 16:20:43 1998
%
%   VOICEBOX home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
%
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%   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
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%   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%   GNU General Public License for more details.
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[nf,p]=size(ls);
p1=p+1;
p2 = p1*2;
ar=zeros(nf,p1);
for k=1:nf
  le=exp(ls(k,:)*pi*2i);
  lf=[1 le -1 conj(fliplr(le))];
  y=real(poly(lf(1:2:p2)));
  x=real(poly(lf(2:2:p2)));
  ar(k,:)=(x(1:p1)+y(1:p1))/2;
end