[petsc-users] implementation of multi-level grid in petsc

[Roc Wang]

Thanks Mat,

    I tried Chombo for implementing AMR but not tried SAMRAI yet. Chombo can do AMR, but it seems the data structure is quite complicated for customizing usage.  What I want to do with petsc is to compose a simple "home-made" like blocked multi-level grid, though it is not automatically adaptive.  However, I don't have too much experiences on petsc. As of now, I suppose to use DM to manage the data for the big domain and all small sub-domains.  I am not sure whether it is a good idea.  So, any suggestions are appreciated very much.  Thanks again.

Best,


    

Date: Thu, 8 Aug 2013 14:03:53 -0500
Subject: Re: [petsc-users] implementation of multi-level grid in petsc
From: knepley at gmail.com
To: pengxwang at hotmail.com
CC: petsc-users at mcs.anl.gov

On Thu, Aug 8, 2013 at 1:29 PM, Roc Wang <pengxwang at hotmail.com> wrote:




Hi,

    I am working on multi-level grid for Poisson equation.  I need to refine some sub-region in the computational domain. To this, I plan to build  some boxes (patches) based on the coarsest level. I am using DM to manage the data. I found there is a new function DMPatachCreate() in the version 3.4.  Is this function the right one I should use for the refined region?  If it is not, which ones I should use?


That is an experiment and does not work. 
    My proposed approach is to start with  code dm/impls/patch/examples/tests/ex1.c. And then follow the code /dm/examples/tutorials/ex65dm.c. Is this approach the right way to my goal?

    In addition, I need to use not only the nodes but also the cells including nodes.  Should I use DMMesh to create the cells? I noticed DMMesh is mainly for unstructured grid, but I didn't find other class that implements structured cells.  Can anybody give me some suggestions on multi-level grid or let me know which examples I should start with? Thanks.

 		 	   		  

No, that is not appropriate.
It sounds like you want structured AMR. PETSc does not do this, and there are packages that do it.:

a) Chombo
b) SAMRAI
which are both patch-based AMR. If you want octree-style AMR you could use p4est, but it would mean
a lot of coding along the lines of http://arxiv.org/abs/1308.1472, or Deal.II which is a complete package.I think Deal is the closest to using PETSc solvers.

  Thanks,
     Matt
-- 
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.

-- Norbert Wiener
 		 	   		  
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