Hello,

I wanted to thank everyone for the help and say that I managed to get it 
running on the cluster and I have done some efficiency calculations. To run the 
code I used,

mpirun -np # ./ex45 -da_grid_x 5 -da_grid_y 5 -da_grid_z 5 -da_refine 6 
-ksp_monitor -pc_type mg -mg_levels_ksp_type richardson -mg_levels_pc_type sor 
-log_summary

as suggested and found the following

p(#cpu) Tp (parallel)           T1 (serial)     Efficiency [ = Tp/(p*T1) ]
--------------------------------------------------------------------------------------
1               904                             904                     1.00
2               553                             904                     0.82
4               274                             904                     0.83
8               138                             904                     0.82
16              70                              904                     0.81
32              36                              904                     0.78

It seems to scale beautifully starting at 2 but there is a big drop from 1 to 
2.  I suspect there's a very good reason for this, I just don't know what.

Thanks again for all of your help,
Francis

On 2012-02-24, at 12:59 PM, Jed Brown wrote:

> On Fri, Feb 24, 2012 at 11:49, Francis Poulin <fpoulin at uwaterloo.ca> wrote:
> I don't seem to have the hydra in my bin folder but I do have petscmpiexec 
> that I've been using.
> 
> That's just the name of my mpiexec. Use whichever one is used with your build 
> of PETSc.
>  
> 
>> 
>> Use these, it will run the same method and sizes as the options I gave for 
>> ex22 before.
>> 
>> mpiexec.hydra -n 2 ./ex45 -da_grid_x 5 -da_grid_y 5 -da_grid_z 5 -da_refine 
>> 5 -ksp_monitor -pc_type mg -mg_levels_ksp_type richardson -mg_levels_pc_type 
>> sor -log_summary
>>  
> 
> Also, I want to install PetSc on an SGI machine that I have access to.  I 
> have been told that using MPT would give better performance compared to 
> mpich2.  When I configure petsc on this server I don't suppose
> 
> -with-mpi-dir=/opt/sgi/mpt
> 
>  the above would work because of the different name.  Do you have a 
> suggestion as to what I could try?  
> 
> It's just the way you launch parallel jobs.

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