Am Dienstag, den 30.08.2011, 10:08 -0600 schrieb John Peterson:
> On Tue, Aug 30, 2011 at 9:56 AM, robert <[email protected]> wrote:
> >
> > The mesh.uniformly_refine(1) takes some minutes when I do it in serial
> > on my PC. However, on the BlueGene/P it doesn't come to an end (I
> > aborted after 15 min). Do I have to prepare my mesh in a special way for
> > use in parallel? One thing I have tried was to call the
> > prepare_for_use() before the refinement. I thought this makes sense
> > because the mesh is partitioned before. But, the problem remains.
> 
> Your mesh is serial unless you specifically compiled libmesh with
> --enable-parmesh.

Ok, but nevertheless it shouldn't be slower than on my PC, or am I
wrong?

Would this option just work with the existing code or do I have to
change to ParallelMesh?

> 
> What this means is that the mesh data structure (and any refinements,
> etc.) is duplicated on all processors -- convenient for writing code,
> not great for conserving memory.
> 
> And it's particularly bad on multicore shared memory architectures:
> you will have one copy of the mesh per MPI process, typically that
> means one per core.
> 
> > Mesh Information:
> >  Mesh Information:
> >  mesh_dimension()=3
> >  spatial_dimension()=3
> >  n_nodes()=447273
> >    n_local_nodes()=447273
> >  n_elem()=2994336
> >    n_local_elem()=2994336
> >    n_active_elem()=2661632
> >  n_subdomains()=2
> >  n_processors()=1
> >  processor_id()=0
> 
> You may be going into swap depending on how little memory is available
> per core on this machine, but 3M elements isn't particularly huge....
> so
> 
> .) How much memory do you have per core?

–  SMP mode : 4 GB of physical memory available to the MPI task
   running on each node (4 cores/node)

For testing and learning I only use a partition of 32 nodes.

> .) What is going on in 'top' or the equivalent on BGL when your code is 
> running?
What do you mean by this? Excuse my question - I am just not the most
experienced person with computers.  



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