[Libmesh-users] Question about unique_ids

[David K. <dav...@ak...>]

I'd like to use unique_ids to identify elements and nodes without worrying
about renumbering, but before I do that I'd like to understand a bit more
about how unique_ids are defined.

In particular, what is the idea behind how we generate the unique_ids? From
the code in replicated_mesh.C, for example, it looks like the unique_ids
are set in add_node and add_elem, with _next_unique_id being incremented
each time a new ID is set. This looks simple enough, but I was wondering if
there's anything else to it?

One concrete question I have is if I create two Mesh objects by reading in
the same mesh exodus file twice, will those two meshes have matching
unique_ids? I guess they will simply because "add_node" and "add_elem" will
be called in the same order during those two read operations.

Thanks!
David