From: Victor Eijkhout <eijkhout@prancer.cs.utk.edu>
Newsgroups: sci.math.num-analysis
Subject: Re: Accelerating Laplace Solver
Date: 16 Dec 1998 12:10:45 -0500

Charles Bond <cbond@ix.netcom.com> writes:

> I've been using a 'plain vanilla'  difference equation
> iterative solver for solving Laplace's equation on a
> rectangular grid.

Why is everyone recommending multigrid? Unless you can find a package
that takes a lot of programming. If you're really solving Laplace
you can use FFTs, ADI, or anything else based on separation of variables;
search for Fishpack for starters.

-- 
Victor Eijkhout
"Too many textbooks and discussions leave children free to make 
 up their minds about things." [Fundie Mel Gabler]
==============================================================================

From: Charles Bond <cbond@ix.netcom.com>
Newsgroups: sci.math.num-analysis
Subject: Re: Accelerating Laplace Solver
Date: Wed, 16 Dec 1998 06:44:07 -0800
To: Jun Zhang <jzhang@cs.engr.uky.edu>

Jun,

Thanks for the pointer to MGNET. I wasn't aware of this web site.
It has a virtual gold mine of information useful to me.

Regards,
    C. Bond

Jun Zhang wrote:

> Maybe the best place to llok for useful multigrid
> stuffs is the MGNET at http://www.mgnet.org
>
> You can find papers and software, and even
> experience there.
>
> Reading an expert's book does not help solve
> someone's immediate problems.
>
> Jun Zhang
> ----------
>
> In article <755p2jINN8r3@s4bds.rzg.mpg.de>,
> Bruce Scott TOK <bds@rzg.mpg.de> wrote:
> >In article <3675BA87.A071AA7F@ix.netcom.com>,
> >Charles Bond  <cbond@ix.netcom.com> wrote:
> >>I've been using a 'plain vanilla'  difference equation
> >>iterative solver for solving Laplace's equation on a
> >>rectangular grid. I'd like to get some hints on accelerating
> >>the convergence. Anyone had experience in this area?
> >
> >Conjugate gradient methods and their relatives:  search the web for
> >"Templates" and look up the text on matrix computation by Golub and
> >Ortega.  CG stuff is in (I think) chapter 9.
> >
> >Multigrid methods:  look up A Multigrid Tutorial by Briggs and then the
> >standard text by Hackbusch (Springer).
> >
> >cu,
> >Bruce
> >
> >--
> >"That's the old ecological tale that explains humans' inability to fully
> >appreciate global warming.  To wit: if you drop a frog in a pan of hot
> >water, it jumps out.  If you drop it in a pan of cold water, then turn
> >the heat up slowly, you can roast it to death."  -- Clive Thompson
>
> --
> *************************************************************************
> * Jun Zhang                       * E-mail: jzhang@cs.uky.edu           *
> * Department of Computer Science  * URL:  http://www.cs.uky.edu/~jzhang *
> * University of Kentucky          * Tel:  (606) 257--3892               *
==============================================================================

Newsgroups: sci.math.num-analysis
From: pauldz@cwi.nl (Paul de Zeeuw)
Subject: Re: Accelerating Laplace Solver
Date: Wed, 16 Dec 1998 12:51:22 GMT

See:
http://www.cwi.nl/~pauldz/
and click on: 2D multigrid software, MGD9V.

See also:
E.F.F.\ Botta, K.\ Dekker, Y.\ Notay, A.\ van der Ploeg, C.\ Vuik,
F.W.\ Wubs, P.M.\ de Zeeuw,
How fast the Laplace equation was solved in 1995,
J.\ Applied Numerical Mathematics 24 (1997) 439--455.

See also:
http://www.mgnet.org/

Good luck,
          Paul de Zeeuw
          CWI