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 JonTai July 29, 1999 10:52

Agglomeration Algorithm

Hi,

Can anyone out there please enlighten me on what's Agglomeration Algorithm in Multigrid Technique? Thanks.

Rgds, Jon

 Patrick Godon July 29, 1999 11:57

Re: Agglomeration Algorithm

Hi There,

I think agglomeration is a step carried out in parallel computing and I don't think it has something to do with Multigrid. I have worked with multigrids but I never encountered this 'agglomeration algorithm'. The multigrid method you are working with might have been ported on a Massively Parallel Machine, this would make sens. Multigrids are ideal for parallel computing and that's where they are really efficient.

I might be wrong, then someone will certainly post a message about it, hopefully.

Cheers, Patrick

 Dr. Hrvoje Jasak August 2, 1999 05:07

Re: Agglomeration Algorithm

In order to do multigrid, you need to build a series of meshes with different resolution. Typically, it is not "nice" to ask the user to build all the meshes for you by hand, so you've got a choice: either you get a coarse mesh and then refine it n times (problem with boundary conditions), or you are stuck with the problem of automatic construction of coarse meshes for the user-defined (fine) mesh. The way you do this is to group bunches of fine mesh cells together to create a single coarse cell, which is called AGGLOMERATION. There is a few interesting algorithms, all loosely based on the Cutthil-McKee node renumbering procedure.

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