function L = chol_up (A)
%CHOL_UP up-looking Cholesky factorization.
% Example:
%   L = chol_up (A)
% See also: cs_demo

%   Copyright 2006-2007, Timothy A. Davis.
%   http://www.cise.ufl.edu/research/sparse

n = size (A) ;
L = zeros (n) ;
for k = 1:n
    L (k,1:k-1) = (L (1:k-1,1:k-1) \ A (1:k-1,k))' ;
    L (k,k) = sqrt (A (k,k) - L (k,1:k-1) * L (k,1:k-1)') ;
end