Re: [petsc-dev] WTF

2016-06-30 Thread Yang, Ulrike Meier
That might be the way to go ☺ Ulrike From: Jeff Hammond [mailto:jeff.scie...@gmail.com] Sent: Thursday, June 30, 2016 11:49 AM To: Yang, Ulrike Meier Cc: Barry Smith ; Justin Chang ; PETSc ; Falgout Rob (rfalg...@llnl.gov) Subject: Re: [petsc-dev] WTF > The default settings often don’t work we

Re: [petsc-dev] WTF

2016-06-30 Thread Jeff Hammond
> The default settings often don’t work well for 3D problems. Are 2D (1D?) problems really the common case for PDE solvers? Aren't interesting problems 3D? Shouldn't the defaults be set to optimize for 3D? Jeff -- Jeff Hammond jeff.scie...@gmail.com http://jeffhammond.github.io/

Re: [petsc-dev] WTF

2016-06-30 Thread Yang, Ulrike Meier
Hi Barry, It would not be possible to detect whether this is 3D, but we could add a function like hypre_BoomerAMGSet3D or so which would change the default settings or we could change the default settings (I have been hesitant to do so, since the current settings still seem to work better for 2

Re: [petsc-dev] WTF

2016-06-30 Thread Barry Smith
> On Jun 30, 2016, at 9:55 AM, Yang, Ulrike Meier wrote: > > Do you know which settings were used for BoomerAMG? > The default settings often don’t work well for 3D problems. Ulrike, Would it be possible for BoomerAMG to detect the dimension, or use dimension information provided by the

Re: [petsc-dev] WTF

2016-06-30 Thread Matthew Knepley
On Thu, Jun 30, 2016 at 4:55 PM, Yang, Ulrike Meier wrote: > Do you know which settings were used for BoomerAMG? > > The default settings often don’t work well for 3D problems. > > Ulrike, the default setting were not coarsening aggressively enough. The FireDrake guys used these which seem to wor

Re: [petsc-dev] WTF

2016-06-30 Thread Yang, Ulrike Meier
Do you know which settings were used for BoomerAMG? The default settings often don’t work well for 3D problems. Ulrike From: Justin Chang [mailto:jychan...@gmail.com] Sent: Thursday, June 30, 2016 12:40 AM To: Barry Smith Cc: Jeff Hammond ; Yang, Ulrike Meier ; PETSc ; Falgout Rob (rfalg...@lln

Re: [petsc-dev] WTF

2016-06-30 Thread Jeff Hammond
On Wed, Jun 29, 2016 at 8:18 PM, Barry Smith wrote: > > > On Jun 29, 2016, at 10:06 PM, Jeff Hammond > wrote: > > > > > > > > On Wednesday, June 29, 2016, Barry Smith wrote: > > > >Who are these people and why to they have this webpage? > > > > > > Pop up 2-3 directories and you'll see this

Re: [petsc-dev] WTF

2016-06-30 Thread Andrew McRae
Justin, Note that the Firedrake authors did their own Poisson scaling in the firedrake paper (arXiv ), and they needed to set custom BoomerAMG options to get good performance. See pages 6 and 16-18. If I recall correctly, with the out-of-the-box options, far too

Re: [petsc-dev] WTF

2016-06-30 Thread Justin Chang
That guy's results actually make sense to me. I also get poor strong-scaling for the FEM version of the poisson equation (via firedrake) using HYPRE's boomerAMG. The studies were done on Intel E5-2670 machines and had proper OpenMPI bindings.No HYPRE configure options were set via command line so