Hi Matt We are trying to do a simple FE using DMPlex, but when assemble the global stiffness matrix we get in problems when running NP>1 - that is the global matrix differs when we move to a distributed system, where it should not.
In pseudo-code our CreateGlobalStiffnessMatrix does the following create a local stiffness matrix ke with some values for each local cell/element e (using result from DMPlexGetHeightStratum(..,0,..) for each of its vertices (using DMPlexGetTransitiveClosure(..,e,..) set local/global mapping to edof update the global stiffness matrix K using the local mapping edof and values ke The code we have sent is a simplified version, which just builds a dummy stiffness matrix - but we believe this matrix should still the same independent of NP. (That is why we use trace). I'm not familiar with MatSetValuesClosure(). Is that the missing piece? Kind regards, Morten ________________________________ From: Matthew Knepley [knep...@gmail.com] Sent: Monday, September 26, 2016 2:19 PM To: Morten Nobel-Jørgensen Cc: PETSc [petsc-users@mcs.anl.gov] Subject: Re: [petsc-users] DMPlex problem On Mon, Sep 26, 2016 at 7:00 AM, Morten Nobel-Jørgensen <m...@dtu.dk<mailto:m...@dtu.dk>> wrote: Hi Matthew It seems like the problem is not fully fixed. I have changed the code to now run on with both 2,3 and 4 cells. When I run the code using NP = 1..3 I get different result both for NP=1 to NP=2/3 when cell count is larger than 2. Do you mean the trace? I have no idea what you are actually putting in. I have a lot of debugging when you use, MatSetValuesClosure(), but when you directly use MatSetValuesLocal(), you are handling things yourself. Thanks, Matt Kind regards, Morten ____ mpiexec -np 1 ./ex18k cells 2 Loc size: 36 Trace of matrix: 132.000000 cells 3 Loc size: 48 Trace of matrix: 192.000000 cells 4 Loc size: 60 Trace of matrix: 258.000000 mpiexec -np 2 ./ex18k cells 2 Loc size: 24 Loc size: 24 Trace of matrix: 132.000000 cells 3 Loc size: 36 Loc size: 24 Trace of matrix: 198.000000 cells 4 Loc size: 36 Loc size: 36 Trace of matrix: 264.000000 mpiexec -np 3 ./ex18k cells 2 Loc size: 24 Loc size: 24 Loc size: 0 Trace of matrix: 132.000000 cells 3 Loc size: 24 Loc size: 24 Loc size: 24 Trace of matrix: 198.000000 cells 4 Loc size: 36 Loc size: 24 Loc size: 24 Trace of matrix: 264.000000 ________________________________ From: petsc-users-boun...@mcs.anl.gov<mailto:petsc-users-boun...@mcs.anl.gov> [petsc-users-boun...@mcs.anl.gov<mailto:petsc-users-boun...@mcs.anl.gov>] on behalf of Morten Nobel-Jørgensen [m...@dtu.dk<mailto:m...@dtu.dk>] Sent: Sunday, September 25, 2016 11:15 AM To: Matthew Knepley Cc: PETSc [petsc-users@mcs.anl.gov<mailto:petsc-users@mcs.anl.gov>] Subject: Re: [petsc-users] DMPlex problem Hi Matthew Thank you for the bug-fix :) I can confirm that it works :) And thanks for your hard work on PETSc - your work is very much appreciated! Kind regards, Morten ________________________________ From: Matthew Knepley [knep...@gmail.com<mailto:knep...@gmail.com>] Sent: Friday, September 23, 2016 2:46 PM To: Morten Nobel-Jørgensen Cc: PETSc [petsc-users@mcs.anl.gov<mailto:petsc-users@mcs.anl.gov>] Subject: Re: [petsc-users] DMPlex problem On Fri, Sep 23, 2016 at 7:45 AM, Matthew Knepley <knep...@gmail.com<mailto:knep...@gmail.com>> wrote: On Fri, Sep 23, 2016 at 3:48 AM, Morten Nobel-Jørgensen <m...@dtu.dk<mailto:m...@dtu.dk>> wrote: Dear PETSc developers Any update on this issue regarding DMPlex? Or is there any obvious workaround that we are unaware of? I have fixed this bug. It did not come up in nightly tests because we are not using MatSetValuesLocal(). Instead we use MatSetValuesClosure() which translates differently. Here is the branch https://bitbucket.org/petsc/petsc/branch/knepley/fix-dm-ltog-bs and I have merged it to next. It will go to master in a day or two. Also, here is the cleaned up source with no memory leaks. Matt Also should we additionally register the issue on Bitbucket or is reporting the issue on the mailing list enough? Normally we are faster, but the start of the semester was hard this year. Thanks, Matt Kind regards, Morten ________________________________ From: Matthew Knepley [knep...@gmail.com<mailto:knep...@gmail.com>] Sent: Friday, September 09, 2016 12:21 PM To: Morten Nobel-Jørgensen Cc: PETSc [petsc-users@mcs.anl.gov<mailto:petsc-users@mcs.anl.gov>] Subject: Re: [petsc-users] DMPlex problem On Fri, Sep 9, 2016 at 4:04 AM, Morten Nobel-Jørgensen <m...@dtu.dk<mailto:m...@dtu.dk>> wrote: Dear PETSc developers and users, Last week we posted a question regarding an error with DMPlex and multiple dofs and have not gotten any feedback yet. This is uncharted waters for us, since we have gotten used to an extremely fast feedback from the PETSc crew. So - with the chance of sounding impatient and ungrateful - we would like to hear if anybody has any ideas that could point us in the right direction? This is my fault. You have not gotten a response because everyone else was waiting for me, and I have been slow because I just moved houses at the same time as term started here. Sorry about that. The example ran for me and I saw your problem. The local-tp-global map is missing for some reason. I am tracking it down now. It should be made by DMCreateMatrix(), so this is mysterious. I hope to have this fixed by early next week. Thanks, Matt We have created a small example problem that demonstrates the error in the matrix assembly. Thanks, Morten -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener