Re: [Libmesh-users] question about read-in mesh

[Stogner, R. H <roy...@ic...>]

On Mon, 6 May 2019, Povolotskyi, Mykhailo wrote:

> I'm having difficulties in reading mesh in parallel and using it after.
>
> The documentation says:
>
> void libMesh::GmshIO::read_mesh     (     std::istream & in    )
>
> {
>
> // This is a serial-only process for now;
>
> // the Mesh should be read on processor 0 and
>
> // broadcast later
>
>
> }
>
> How should the mesh be broadcast? After prepare_for_use() or before?

During, automatically.  Just prepare_for_use() should handle it; you
shouldn't have to do anything else.  If you are it's a bug, and let us
know details!

> If I want to  solve and output the system mesh with VTKIO, do I have to
> serialize the mesh?

I forget whether our VTKIO class handles parallel VTK output properly
automatically or not.  I do know that we handle DistributedMesh
serialization automatically for those MeshOutput classes which require
it, but we do spit out a warning which shouldn't be ignored: generally
for any problem big enough to prompt use of a DistributedMesh, being
forced to serialize it is a performance disaster.
---
Roy