function p = colamd (S) % COLAMD Column approximate minimum degree permutation. % P = COLAMD (S) returns the column approximate minimum degree permutation % vector for the sparse matrix S. For a non-symmetric matrix S, S (:,P) % tends to have sparser LU factors than S. The Cholesky factorization of % S (:,P)' * S (:,P) also tends to be sparser than that of S'*S. COLAMD % tends to be faster than COLMMD and tends to return a better ordering. % % See also COLAMDTREE, SYMAMD, SYMAMDTREE, COLMMD, SYMMMD, SYMRCM, COLPERM. % % Usage: P = colamd (S) % P = colamd (S, knobs) % [P, stats] = colamd (S) % [P, stats] = colamd (S, knobs) % % stats (1) and stats (2) are the number of dense rows and columns % ignored in COLAMD, and stats (3) is the number of garbage collections % performed. knobs (1) and knobs (2) control how COLAMD ignores dense rows % and columns (similar to spparms ('wh_frac')). % % Authors: Stefan I. Larimore and Timothy A. Davis, University of Florida, % (davis@cise.ufl.edu); in collaboration with John Gilbert, Xerox PARC, and % Esmond Ng, Oak Ridge National Laboratory. This work was supported by the % National Science Foundation, under grants DMS-9504974 and DMS-9803599. % COLAMD and SYMAMD are available at http://www.cise.ufl.edu/~davis/colamd. % Tested under Matlab 5.2.0.3084, using Solaris 2.6. August 3, 1998. % This file is provided so that "help colamd" prints the above description. help colamd disp ('Warning! Valid colamd mexFunction not found. Using colmmd instead.') ; p = colmmd (S) ;