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.
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