MATLAB Function Reference 
Sparse symmetric minimum degree ordering
Syntax
Note
symmmd is obsolete and will be removed from a future version of MATLAB. Use symamd instead.

Description
p = symmmd(S)
returns a symmetric minimum degree ordering of S
. For a symmetric positive definite matrix S
, this is a permutation p
such that S(p,p)
tends to have a sparser Cholesky factor than S
. Sometimes symmmd
works well for symmetric indefinite matrices too.
Algorithm
The symmetric minimum degree algorithm is based on the column minimum degree algorithm. In fact, symmmd(A)
just creates a nonzero structure K
such that K'*K
has the same nonzero structure as A
and then calls the column minimum degree code for K
.
See Also
colamd
, colmmd
, colperm
, symamd
, symrcm
References
[1] Gilbert, John R., Cleve Moler, and Robert Schreiber, "Sparse Matrices in MATLAB: Design and Implementation," SIAM Journal on Matrix Analysis and Applications 13, 1992, pp. 333356.
symmlq  symrcm 
© 19942005 The MathWorks, Inc.