Re: [Libmesh-users] Mesh decomposition and node duplication

[Roy S. <roy...@ic...>]

On Mon, 1 Jun 2009, Mengda Wu wrote:

>   I am trying to understand the mesh decomposition and parallelism in
> libmesh.

You might read our paper in Engineering With Computers:
http://www.springerlink.com/content/u753j35775168843/

It's a bit out of date on some things, but I think the SerialMesh
parallelism info is pretty much still accurate.

> (1) The nodes on the decomposition boundaries seem not to duplicate on all
> processors which have elements use those nodes. Is that correct?

Each node or element is duplicated on every processor in a SerialMesh, but is only
owned by one processor.

> (2) For a given element on some processor, How can I know which node is on
> this processor and which is on another?

Check Node::processor_id()

> (3) How libmesh use ghost? ghost on nodes or elements?

Each nonlocal element whose boundary touches the boundary of a
processor's local element will be available locally as a ghost
element.  Every non-local degree of freedom coefficient with support
on such an element will be available as a ghost dof.
---
Roy