Re: [Libmesh-users] enforce to partition mesh on each processor locally

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

On Tue, 13 Mar 2018, Vasileios Vavourakis wrote:

> oh, I thought that the default setting in the Parallel::Communicator (i.e. see default
> constructor: http://libmesh.github.io/doxygen/classlibMesh_1_1Parallel_1_1Communicator.html#a697f8e599333609a45761828e14659c1) for the
> “communicator” is: MPI_COMM_SELF

It is, but init.comm() isn't a default-constructor communicator, it's
a default-for-most-users communicator.  Typically when someone runs on
N processors it's because they want everything parallelized between N
processors, so we make it easy to get an All-N-Processors
communicator.

> unless it gets initialised to MPI_COMM_WORLD somewhere in the
> LibMeshInit - apologies, i’m not always successful looking for some
> details in the library documentation :(

That's a very polite way to say "Why don't you even have a single line
of documentation for LibMeshInit::comm()?"  I would have been tempted
to phrase that with much more cursing.

I'll put together a PR with better comments now, so it'll get into the
online Doxygen eventually.

> I will give it a spin and update libmesh-users asap...

Thanks,
---
Roy