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function [p, stats] = csymamd (S, knobs, cmember) %#ok
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%CSYMAMD constrained symmetric approximate minimum degree permutation
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% P = CSYMAMD(S) for a symmetric positive definite matrix S, returns the
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% permutation vector p such that S(p,p) tends to have a sparser Cholesky
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% factor than S. Sometimes CSYMAMD works well for symmetric indefinite
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% matrices too. The matrix S is assumed to be symmetric; only the
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% strictly lower triangular part is referenced. S must be square. Note
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% that p=amd(S) is faster, but does not allow for a constrained ordering.
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% The ordering is followed by an elimination tree post-ordering.
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% See also AMD, CCOLAMD, COLAMD, SYMAMD.
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% p = csymamd (S,knobs,cmember)
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% knobs is an optional one- to three-element input vector, with a default
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% value of [10 1 0] if present or empty ([ ]). Entries not present are set
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% knobs(1): If S is n-by-n, then rows and columns with more than
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% max(16,knobs(1)*sqrt(n)) entries are ignored, and ordered last in the
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% output permutation (subject to the cmember constraints).
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% knobs(2): if nonzero, aggressive absorption is performed.
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% knobs(3): if nonzero, statistics and knobs are printed.
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% cmember is an optional vector of length n. It defines the constraints on
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% the ordering. If cmember(j)=s, then row/column j is in constraint set s
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% (s must be in the range 1 to n). In the output permutation p,
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% rows/columns in set 1 appear first, followed by all rows/columns in set 2,
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% and so on. cmember=ones(1,n) if not present or empty. csymamd(S,[],1:n)
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% p = csymamd(S) is about the same as p = symamd(S). knobs and its default
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% Authors: S. Larimore, T. Davis (Univ of Florida), and S. Rajamanickam, in
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% collaboration with J. Gilbert and E. Ng. Supported by the National
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% Science Foundation (DMS-9504974, DMS-9803599, CCR-0203270), and a grant
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% from Sandia National Lab. See http://www.cise.ufl.edu/research/sparse
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% for ccolamd, csymamd, amd, colamd, symamd, and other related orderings.
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% See also AMD, CCOLAMD, COLAMD, SYMAMD, SYMRCM.
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% Copyright 1998-2007, Timothy A. Davis, Stefan Larimore, and Siva Rajamanickam
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% Developed in collaboration with J. Gilbert and E. Ng.
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error ('csymamd: mexFunction not found') ;