Description:

The COLAMD column approximate minimum degree ordering algorithm
computes a permutation vector P such that the LU factorization of A
(:,P) tends to be sparser than that of A. The Cholesky factorization
of (A (:,P))'*(A (:,P)) will also tend to be sparser than that of
A'*A. SYMAMD is a symmetric minimum degree ordering method based on
COLAMD, available as a MATLAB-callable function. It constructs a
matrix M such that M'*M has the same pattern as A, and then uses
COLAMD to compute a column ordering of M. Colamd and symamd tend to be
faster and generate better orderings than their MATLAB counterparts,
colmmd and symmmd.