[petsc-users] HYPRE BOOMERAMG no output

[Smith, Barry F.]

> 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