First http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind
then ask again > On Dec 13, 2017, at 10:07 AM, Hao Zhang <[email protected]> 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 <[email protected]> wrote: > Thanks. Barry. > > > > On Tue, Dec 12, 2017 at 2:03 PM, Smith, Barry F. <[email protected]> wrote: > > > > On Dec 12, 2017, at 12:04 PM, Hao Zhang <[email protected]> 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 [email protected]). > > 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
