[CIG-SHORT] Change in dt means new Jacobian

[Birendra jha]

Dear developers 

I simplified my problem setup to see if no. of KSP iterations goes down. There are 46552 nodes, 42525 hex elements in a box.  In this very simple setup, both ASM and ML preconditioner takes ~90 iterations for convergence. 
Attached are the cfg files and stdout from LU and ML preconditioners. ASM stdout is not attached.

Why does the run with LU crash? I just used following 2 lines to use LU:
[pylithapp.petsc]
pc_type = lu
Is it incorrect?

For both ASM and ML, the solution looks correct in Paraview. It's just the time taken in integrating residual that I would like to reduce. 

Another question: when Pylith is running on a single multicore machine, can it use OpenMPI instead of MPI (I am assuming it's using MPI by default)? 

Thanks and regards
Birendra

--- On Tue, 9/4/12, Brad Aagaard <baagaard at usgs.gov> wrote:

> From: Brad Aagaard <baagaard at usgs.gov>
> Subject: Re: Change in dt means new Jacobian
> To: "Birendra jha" <bjha7333 at yahoo.com>
> Cc: cig-short at geodynamics.org
> Date: Tuesday, September 4, 2012, 7:59 PM
> On 09/03/2012 08:54 PM, Birendra jha
> wrote:
> > 3. How do I utilize multiple cores on a single machine?
> Sorry if this
> > question is already answered somewhere. I found
> instructions on
> > running parallel using a batch system but don't know
> how to run on 1
> > node and use multiple cores. Does this require
> re-building Pylith?
> 
> To run in parallel all you have to do is add the command
> line argument --nodes=NUM_CORES. You do not need to
> rebuild.
> 
> > 4. For HDF5 output, is it correct that the I have to
> wait until
> > finish to get the xmf file which is needed to load h5
> files in
> > Paraview? Manual says "This file is written when PyLith
> closes the
> > HDF5 file at the end of the simulation".
> 
> The Xdmf file is written when PyLith closes the HDF5 file at
> the end of a simulation. There is a python script included
> with PyLith called pylith_genxdmf that will generate the
> Xdmf file given an HDF5 file. This is handy if a simulation
> did not finish or you add additional fields to an existing
> HDF5 file. Generating the Xdmf file in the middle of a
> simulation can work but it is risky because the HDF5 file
> can get corrupted if multiple processes try to access the
> file simultaneously.
> 
>   pylith_genxdmf --file=HDF5_FILE
> 
> Brad
>
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