[petsc-users] testing scalability for ksp/ex22.c

[Barry Smith]

On Feb 24, 2012, at 9:54 AM, Francis Poulin wrote:

> Hello again,
> 
> I am now running v3.2p6 and working with ksp/ex45.c, as suggested.
> 
> When I try running ex22 like Jed suggested it works fine.
> 
> When I try running ex45 like Barry suggested it runs but it does not seem to recognize two options.
> 
> WARNING! There are options you set that were not used!
> WARNING! could be spelling mistake, etc!
> Option left: name:-mg_levels_ksp_type value: richardson
> Option left: name:-mg_levels_pc_type value: sor

   You likely need -pc_type mg   Also run with -ksp_view to see what solver it is using NEVER assume you know what solver it is using without explicitly checking with -ksp_view


> 
> Also, I am getting an message saying that it is running it with the debugger and I should rerun ./configure to turn it off and it will run 2 or 3 times faster.  Does that mean that the installation always uses the debugger or never uses it?  I thought I would like it keep it for testing, assuming i figure out how it works, but then turn it off for serious runs.

   By default we build the debug version which has more error checking and all the debug symbols. You should use this for ALL code development and testing of correctness. For production runs and testing of SPEED you should run ./configure WITH A DIFFERENT string name for PETSC_ARCH with the ./configure option --with-debugging=0

   Barry

> 
> Thanks again,
> Francis
> 
> On 2012-02-23, at 11:30 PM, Barry Smith wrote:
> 
>> 
>> On Feb 23, 2012, at 8:24 PM, Jed Brown wrote:
>> 
>>> On Thu, Feb 23, 2012 at 18:58, Francis Poulin <fpoulin at uwaterloo.ca> wrote:
>>> I can do it for each of them if that helps but I suspect the method is the same so I'm sending the information for the first 3, n = 2, 4, 8.  In the mean  time I will figure out how to change the number of levels..
>>> 
>>> There are only three levels. The coarsest level has 32k degrees of freedom, which is very expensive to solve (redundantly) with a direct solver.
>>> 
>>> Run this, it's higher resolution and will be much faster than what you had.
>>> 
>>> mpiexec -n 2 ./ex22 -da_grid_x 5 -da_grid_y 5 -da_grid_z 5 -dmmg_nlevels 6 -ksp_monitor -mg_levels_ksp_type richardson -mg_levels_pc_type sor -log_summary
>>> 
>>> 
>>> Also, please switch to a more recent release of PETSc as soon as possible and do not develop new code using DMMG since that component has been removed (and its functionality incorporated into SNES and KSP).
>> 
>> Using Petsc Release Version 3.1.0, Patch 4, Fri Jul 30 14:42:02 CDT 2010
>> 
>> Goodness gracious, you won't run performance tests on your grandpa's desk calculator would you? Switch to petsc-dev immediately http://www.mcs.anl.gov/petsc/developers/index.html and use src/ksp/ksp/examples/tutorials/ex45.c and use the options -ksp_monitor -mg_levels_ksp_type richardson -mg_levels_pc_type sor -log_summary -da_refine 6
>> 
>>  Barry
>> 
>