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Re: MeshDistribute() and Chaco

1) Please send these to petsc-maint@xxxxxxxxxxx

On 6/14/07, Shi Jin <jinzishuai@xxxxxxxxx> wrote: 
Hi,

I am trying to study the new unstructured mesh part
provided by the new Petsc. I have one particular
question  with regard to the function call
MeshDistribute(serialMesh, PETSC_NULL, &parallelMesh);


2) The PETSC_NULL can be used to specify another partitioner like "parmetis"

3) Not sure about the argument. You would have to refer to the package.

  Matt

This call obviously needs the chaco package to run in
parallel since otherwise I will get a warning to
configure with --download-chaco.
So I ran it with chaco installed. The code works but
the domain decomposition is valid but far from good.
In the attached image, I am showing the domain
decomposition for  a 2-dimensional 1x1 box with two
processes, using the following statements:
MeshCreatePCICE(comm, 3,
"bratu_2d.nodes","bratu_2d.lcon",PETSC_FALSE,PETSC_FALSE,
&serialMesh);
MeshDistribute(serialMesh, PETSC_NULL, &parallelMesh);

I am wondering if it is possible to improve the domain
decomposition by passing some command arguments. I
realized that there are Chaco options such as
-mat_partitioning_chaco_global (found at
http://www-unix.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/MatOrderings/MAT_PARTITIONING_Chaco.html)
. However, when I pass these options to my code, it is
not recognized. I wonder how chaco is used in Petsc
and how I can change its behavior.

In addition, is it possible to use other graph
decomposition packages such as ParMetis to implement
MeshDistribute()? I tried to enable ParMetis without
chaco but the code didn't run and warned me to install
chaco.

Any advice is valuable. Thank you very much.

Shi



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