function a = r2a( r )
% function a = r2a( r )
% 
% Convert Reflexion Coefficients to Predictor Coefficients 
%
% Author: Markus Hauenstein
% Date:   30.12.2001

r = r(:);
P = length( r );
A = zeros(P+1,P+1);
A(1,:) = ones(1,P+1);

for m = 1:P,
  for i = 1:m-1,
     A(i+1,m+1) = A(i+1,m) - r(m) * A(m-i+1,m);
  end
  A(m+1,m+1) = r(m);
end
a = A(2:P+1,P+1);