Re: [petsc-users] Petsc ILU PC Change between 3.6.4 and 3.7.x?

2017-08-23 Thread Barry Smith
In complicated scenarios with deep nesting of solvers it is sometimes not possible to set the options for the deeply nested solvers directly from the code with function calls. Thus we recommend using the options database for such cases. Note that one can provide options on the command line,

Re: [petsc-users] Petsc with OpenMP

2017-08-23 Thread Matthew Knepley
On Wed, Aug 23, 2017 at 6:42 AM, Khai Pham wrote: > Hi All, > > I searched for the information about Petsc with OpenMP support. I came > cross Danyang Su question a couple of month ago at > https://lists.mcs.anl.gov/pipermail/petsc-users/2017-June/032975.html >

[petsc-users] Petsc with OpenMP

2017-08-23 Thread Khai Pham
Hi All, I searched for the information about Petsc with OpenMP support. I came cross Danyang Su question a couple of month ago at https://lists.mcs.anl.gov/pipermail/petsc-users/2017-June/032975.htmlhttps://lists.mcs.anl.gov/pipermail/petsc-users/2017-June/032975.html . I tried to configure

Re: [petsc-users] Petsc ILU PC Change between 3.6.4 and 3.7.x?

2017-08-23 Thread Lawrence Mitchell
On 23/08/17 07:51, Klaij, Christiaan wrote: > Lawrence, > > Well, I was looking for something like SubPCFactorSetShiftType, > or is it supposed to somehow "trickle down" to the sub pc's? Ah, I see. No, the approach below is what you need. Imagine that you used a sub_pc inside a multigrid

Re: [petsc-users] Petsc ILU PC Change between 3.6.4 and 3.7.x?

2017-08-23 Thread Klaij, Christiaan
Lawrence, Well, I was looking for something like SubPCFactorSetShiftType, or is it supposed to somehow "trickle down" to the sub pc's? Or should I setup the pc, get the sub-pc's and then apply PCFactorSetShiftType on the sub pc's, something like CALL KSPSetup(ksp) CALL PCBJacobiGetSubKSP(ksp,

Re: [petsc-users] Petsc ILU PC Change between 3.6.4 and 3.7.x?

2017-08-23 Thread Matthew Knepley
On Wed, Aug 23, 2017 at 2:30 AM, Barry Smith wrote: > >Some argue that the preconditioned residual is "closer to" the norm of > the error than the unpreconditioned norm. I don't have a solid mathematical > reason to prefer left preconditioning with the preconditioned

Re: [petsc-users] Petsc ILU PC Change between 3.6.4 and 3.7.x?

2017-08-23 Thread Barry Smith
Some argue that the preconditioned residual is "closer to" the norm of the error than the unpreconditioned norm. I don't have a solid mathematical reason to prefer left preconditioning with the preconditioned norm. Barry > On Aug 22, 2017, at 11:27 PM, Klaij, Christiaan

Re: [petsc-users] Petsc ILU PC Change between 3.6.4 and 3.7.x?

2017-08-23 Thread Klaij, Christiaan
Barry, Thanks for the explanation. We do have some rare cases that give false convergence, but decided to use CALL KSPSetNormType(ksp,KSP_NORM_UNPRECONDITIONED,ierr) so that convergence is always based on the true residual. Our results are much more consistent now. So that could have been