[petsc-users] HYPRE BOOMERAMG no output

[Smith, Barry F.]

First 

http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind

then ask again


> On Dec 13, 2017, at 10:07 AM, Hao Zhang <hbcbh1999 at gmail.com> wrote:
> 
> CFD is 3D with problem size 150 X 20 X 400 for X, Y and Z direction. : If I'm using less total number of processors conducting parallel simulation, the code runs but at late simulating time, my matrix will have 0 max and min singular value out of nowhere, which confuses me deeply. when I double the total number of processors, my simulations halt at late simulating time. I have petsc running options on but no more output no error message. It's been 12 hours. very weird.
> 
> to sum up, 3 problems are:
> (1) max(min) singular value  of matrix is 0s starting at late time out of nowhere with or without BOOMERAMG
> (2) different number of processors BOOMERAMG behaves very differently
> (3) petsc part halt for unknown reason without crashing or any information
> 
> On Tue, Dec 12, 2017 at 9:09 PM, Hao Zhang <hbcbh1999 at gmail.com> wrote:
> Thanks. Barry.
> 
> 
> 
> On Tue, Dec 12, 2017 at 2:03 PM, Smith, Barry F. <bsmith at mcs.anl.gov> wrote:
> 
> 
> > On Dec 12, 2017, at 12:04 PM, Hao Zhang <hbcbh1999 at gmail.com> wrote:
> >
> > hi,
> >
> > before I introduce HYPRE with BOOMERAMG to my CFD code, I will have output with good convergence rate. with BOOMERAMG, the same code will take longer time to run and there's a good chance that no output will be produced whatsoever.
> 
>   Are you running with -ksp_monitor -ksp_view_pre -ksp_converged_reason ?
> 
>   If you are using -ksp_monitor and getting no output it could be that hypre is taking a very long time to form the AMG preconditioner, but I won't expect to see this unless the problem is very very big.
> 
>    You can always run with -start_in_debugger and then type cont in the debugger wait a couple minutes and then use control C in the debugger and type where to determine what it is doing at the time (you can email the output to petsc-maint at mcs.anl.gov).
> 
>    Boomeramg is not good for all classes of matrices, it is fine for elliptic/parabolic generally but if you hand it something that is hyperbolically dominated it will not work well.
> 
>    Barry
> 
> >
> > what happened? thanks!
> >
> > --
> > Hao Zhang
> > Dept. of Applid Mathematics and Statistics,
> > Stony Brook University,
> > Stony Brook, New York, 11790
> 
> 
> 
> 
> -- 
> Hao Zhang
> Dept. of Applid Mathematics and Statistics,
> Stony Brook University, 
> Stony Brook, New York, 11790
> 
> 
> 
> -- 
> Hao Zhang
> Dept. of Applid Mathematics and Statistics,
> Stony Brook University, 
> Stony Brook, New York, 11790