Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Kong, Fande
Thanks, Barry, On Wed, Nov 15, 2017 at 4:04 PM, Smith, Barry F. wrote: > > Do the ASM runs for thousands of time-steps produce the same final > "physical results" as the MUMPS run for thousands of timesteps? While with > SuperLU you get a very different "physical

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Smith, Barry F.
Do the ASM runs for thousands of time-steps produce the same final "physical results" as the MUMPS run for thousands of timesteps? While with SuperLU you get a very different "physical results"? Barry > On Nov 15, 2017, at 4:52 PM, Kong, Fande wrote: > > > > On

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Kong, Fande
On Wed, Nov 15, 2017 at 3:35 PM, Smith, Barry F. wrote: > > Since the convergence labeled linear does not converge to 14 digits in > one iteration I am assuming you are using lagged preconditioning and or > lagged Jacobian? > We are using Jacobian-free Newton. So Jacobian

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Smith, Barry F.
Since the convergence labeled linear does not converge to 14 digits in one iteration I am assuming you are using lagged preconditioning and or lagged Jacobian? What happens if you do no lagging and solve each linear solve with a new LU factorization? Barry > On Nov 15, 2017, at

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Kong, Fande
On Wed, Nov 15, 2017 at 2:52 PM, Smith, Barry F. wrote: > > > > On Nov 15, 2017, at 3:36 PM, Kong, Fande wrote: > > > > Hi Barry, > > > > Thanks for your reply. I was wondering why this happens only when we use > superlu_dist. I am trying to understand

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Mark Adams
To be clear: these differences completely go away with MUMPS? Can you valgrind this? We have seen some valgrind warning from MUMPS from BLAS routines. It could be that your BLAS is buggy (and SuperLU uses some BLAS routines that MUMPS does not). I think SuperLU does more/different pivoting than

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Matthew Knepley
On Wed, Nov 15, 2017 at 4:36 PM, Kong, Fande wrote: > Hi Barry, > > Thanks for your reply. I was wondering why this happens only when we use > superlu_dist. I am trying to understand the algorithm in superlu_dist. If > we use ASM or MUMPS, we do not produce these differences.

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Smith, Barry F.
> On Nov 15, 2017, at 3:36 PM, Kong, Fande wrote: > > Hi Barry, > > Thanks for your reply. I was wondering why this happens only when we use > superlu_dist. I am trying to understand the algorithm in superlu_dist. If we > use ASM or MUMPS, we do not produce these

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Kong, Fande
Hi Barry, Thanks for your reply. I was wondering why this happens only when we use superlu_dist. I am trying to understand the algorithm in superlu_dist. If we use ASM or MUMPS, we do not produce these differences. The differences actually are NOT meaningless. In fact, we have a real transient

Re: [petsc-users] superlu_dist produces random results

2017-11-15 Thread Smith, Barry F.
Meaningless differences > On Nov 15, 2017, at 2:26 PM, Kong, Fande wrote: > > Hi, > > There is a heat conduction problem. When superlu_dist is used as a > preconditioner, we have random results from different runs. Is there a random > algorithm in superlu_dist? If we

[petsc-users] superlu_dist produces random results

2017-11-15 Thread Kong, Fande
Hi, There is a heat conduction problem. When superlu_dist is used as a preconditioner, we have random results from different runs. Is there a random algorithm in superlu_dist? If we use ASM or MUMPS as the preconditioner, we then don't have this issue. run 1: 0 Nonlinear |R| = 9.447423e+03