Elmergrid & Metis element types

Mesh generators, CAD programs, and other tools
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pamakela
Posts: 49
Joined: 06 Mar 2010, 18:37

Elmergrid & Metis element types

Post by pamakela »

I made a 3D mesh from a STP file in GMSH and the mesh seems quite ok.. but:

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Elmergrid partitioning meshes:
------------------------------
Making a Metis partitioning for 66530 elements in 3-dimensions.
Nodal Metis partition requires that all the elements are of the same type!
MeshSplitter failed - aborting
.. is the error when I try to run a parallel simulation on the Elmer side. I tried figuring out some elmergrid parameters to fix this, but to no avail.


Thanks,

-PM
pamakela
Posts: 49
Joined: 06 Mar 2010, 18:37

Re: Elmergrid & Metis element types

Post by pamakela »

The fix was quick & easy: just needed to make the whole volume into a Physical Group in Gmsh..
raback
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Re: Elmergrid & Metis element types

Post by raback »

Hi

There are a number of different algorithms used from the Metis package. These may be chosen by an additional parameter {0,1,2,3,4}. Some of the algorithms assume that all elementtypes are the same (I think 0 and 1). Others however should work for any mesh. So say, for example

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ElmerGrid 2 2 mesh -out parmesh -metis 512 2
In your case you perhaps reduced the number of different elements by just choosing one body as a physical group. Generally I prefer to use "Save As" and choose the format 2.0 and tick the box for "Save All". ElmerGrid will then automatically renumber and drop the unnecessary entities. Of course, there may really be cases where only a subset is needed, or one wants to do the numbering in gsmh. Then physical groups may of course be used.

-Peter
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