Note that the guy responded with 'PEBCAK'.... meaning "Problem Exists Between 
Chair And Keyboard"... ie... user error.

I can't reproduce any problems with this.

Derek

On Feb 9, 2010, at 4:35 PM, Roy Stogner wrote:

> 
> Appending a bug report from the web tracker; I think I'm not the only
> one that prefers to worry about this stuff in email?
> 
> The _next_free_unpartitioned_elem_id code is a consequence of
> ParallelMesh: because each processor can have the need to add nodes
> that no other processor can see, but we want those nodes to have
> unique ids just the same, we use modular arithmetic to decide what new
> IDs to give everything.  With N CPUs we work mod N+1, so that for
> instance CPU 0 can add elements 0,5,10,etc. while CPU2 adds 2,7,12...
> and any elements added to all processors at once become elements
> 4,9,14, and so on.  This should temporarily give you some very messy
> and sparse numbering, but MeshBase::prepare_for_use() then renumbers
> everything nicely to give continuous ranges on each processor.
> 
> Not sure how this is causing a bug yet, though.  For one thing, we
> don't do anything that complicated on SerialMesh.
> 
> I'm busy at a conference then on vacation this week; could anyone with
> more Exodus experience see if they can replicate this bug?
> ---
> Roy
> 
> ---------- Forwarded message ----------
> Date: Wed, 27 Jan 2010 18:18:30 +0000
> From: SourceForge.net <[email protected]>
> To: [email protected]
> Subject: [Libmesh-devel] [ libmesh-Bugs-2941168 ]
>     _next_free_unpartitioned_elem_id initialization problem
> 
> Bugs item #2941168, was opened at 2010-01-27 18:18
> Message generated for change (Tracker Item Submitted) made by
> You can respond by visiting:
> https://sourceforge.net/tracker/?func=detail&atid=530254&aid=2941168&group_id=71130
> 
> Please note that this message will contain a full copy of the comment thread,
> including the initial issue submission, for this request,
> not just the latest update.
> Category: None
> Group: None
> Status: Open
> Resolution: None
> Priority: 5
> Private: No
> Submitted By: https://www.google.com/accounts ()
> Assigned to: Nobody/Anonymous (nobody)
> Summary: _next_free_unpartitioned_elem_id initialization problem
> 
> Initial Comment:
> When calling addelem on an unpartitioned element, the element id is set to 
> _next_free_unpartitioned_elem_id which is initialized to the size of the 
> communicator.  This creates a problem for some functions in libmesh that 
> assume the first element id is 0.  For instance, the following code seg 
> faults in ExodusII_IO::write:
> 
>         ::Mesh  libMesh ( 3 );
>         ::ExodusII_IO io ( libMesh );
>         io.verbose ( true );
>         io.read ( "block.e" );
>         io.write ( "out.e" );
> 
> I have attached block.e for verification.
> 
> ----------------------------------------------------------------------
> 
> You can respond by visiting:
> https://sourceforge.net/tracker/?func=detail&atid=530254&aid=2941168&group_id=71130
> 
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