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From: "Tim Davis" <davis@cise.ufl.edu>
Newsgroups: comp.soft-sys.matlab
Subject: Re: FEM substructuring  (static condensation) -> out ot memory; ANSYS can do it
Date: Wed, 4 Jun 2008 11:55:05 +0000 (UTC)
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"A B" <gitsnedbutzi@hotmail.com> wrote in message ...

> Thanks Tim for your hints, I'll try the ordering of the 
> nodes and then use CHOL.
> 
> Can you suggest any introductory book on graphs and/or the 
> combinatorial stuff which would help me make your book 
> more understandable? Maybe there is some book for the 
> introduction to the analysis of sparse algorithms?

Try using CAMD (in SuiteSparse on the File Exchange).  It's
like AMD, except that you can give it a set of ordering
constraints.  You can tell it to order all the "statically
condensed" nodes first, then order all the rest (2
constraint sets).  Then within the sets, the approximate
minimum degree ordering will work its magic, to reduce
fill-in.  Then use the resulting ordering to permute the
matrix for CHOL, or LU.

Off-hand, I'm not sure what book I could suggest, since it
would depend on what other background you have.  I give a
*really* short review of the graph theory in my book, and I
cite some others there.  I think Cormen, Leieserson, and
Rivest (Intro to Algorithms, I think the title is), MIT
Press, is a good book.  That might be too advanced,
depending on your background.