On Fri, Jun 28, 2013 at 11:55 PM, Subramanya Gautam Sadasiva <ssadasiv@purdue.edu> wrote:
1. ABAQUS elsets are not unique.. elements can belong to multiple elsets. However as far as I can see,
libmesh elements can belong to only one subdomain.. being able to be part of multiple subdomains would be very useful though..

This is not an ABAQUS thing... most of our mesh formats (both input and output) require this (elements only being in one subdomain)... in particular ExodusII.  This assumption is made in a LOT of places through the code and wouldn't be easy to change.

If anything - I would say that what you need is maybe something closer to BoundaryInfo for element sets.  Leave subdomain_id alone... and use a richer data structure to allow you have arbitrary groupings of elements.  This is actually something we already do in our code... but we are reading our own proprietary formats for those element groupings and keeping track of that stuff ourselves.
2. MeshBase only allows a unique subdomain name  - subdomain id mapping.. and giving subdomains ids depending on both elset name and element type makes this very hard to use the subdomain_name() function. I do not understand the original motivation for the implementation and I think a simpler scheme should not pose too many problems.

Why do you want your elements set names to have anything to do with element type?  This really shouldn't be necessary with libMesh.
I have implemented code to enable the reader to handle generated element and node  sets (start, end , step)  as well as surfaces that are defined through element sets.

Did you try to attach the code - or is the code somewhere we can take a look at it?