[Libmesh-devel] reduced_basis_ex6 fails on ParallelMesh

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

And it doesn't look like it's ParallelMesh's fault.

RBEIMConstruction::evaluate_mesh_function is querying a MeshFunction
object, and that query returns the _out_of_mesh_value (an empty
DenseVector by default) if it's asked for the value of a point that's
not within any active local or active ghosted elements.

Even with SerialMesh, this would normally fail, except that
RBEIMConstruction built a serialized solution vector to hand to the
MeshFunction, so results should be correct but performance should
scale poorly.

enrich_RB_space() and update_RB_system_matrices() are doing a localize
to that serialized vector, so they must already be parallel_only
methods - would it be possible to change them to only query local
elements, and then if necessary sync the resulting data afterwards?

For now I'm going to disable reduced_basis_ex6 in the --enable-parmesh
case.
---
Roy