1function [R,p,q] = chol2 (A) %#ok 2%CHOL2 sparse Cholesky factorization, A=R'R. 3% Note that A=L*L' (LCHOL) and A=L*D*L' (LDLCHOL) factorizations are faster 4% than R'*R (CHOL2 and CHOL) and use less memory. The LL' and LDL' 5% factorization methods use tril(A). This method uses triu(A), just like 6% the built-in CHOL. 7% 8% Example: 9% R = chol2 (A) same as R = chol (A), just faster 10% [R,p] = chol2 (A) same as [R,p] = chol(A), just faster 11% [R,p,q] = chol2 (A) factorizes A(q,q) into R'*R, where q is 12% a fill-reducing ordering 13% 14% A must be sparse. 15% 16% See also LCHOL, LDLCHOL, CHOL, LDLUPDATE. 17 18% Copyright 2006-2007, Timothy A. Davis, http://www.suitesparse.com 19 20error ('chol2 mexFunction not found') ; 21