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The 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.