[petsc-users] Problems with PCMGSetInterpolation

Mon Sep 12 13:22:17 CDT 2022

It made some progress :-)

It would be quickest if you just sent me your code (you can use petsc-maint at mcs.anl.gov <mailto:petsc-maint at mcs.anl.gov> if you don't want it public).

> Somehow I thought that setting ComputeOperators and ComputeRHS will be enough..

I think it is failing because though you provide code to fill up the matrices you never provide the matrices; it may be implicit in the use of KSPSetComputeOperators
 that you provide a DM that can create the matrices for each of the levels automatically inside the PCSetUp_MG.

Barry

> On Sep 12, 2022, at 1:26 PM, Oleg Shatrov <shatrov.oleg.a at gmail.com> wrote:
> 
> Unfortunately it still failed.
> 
> [0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
> [0]PETSC ERROR: Must call DMShellSetGlobalVector() or DMShellSetCreateGlobalVector()
> [0]PETSC ERROR: See https://petsc.org/release/faq/ <https://petsc.org/release/faq/> for trouble shooting.
> [0]PETSC ERROR: Petsc Development GIT revision: v3.17.3-770-gceb9926454c  GIT Date: 2022-07-15 21:35:25 +0000
> [0]PETSC ERROR: ./a.out on a  named MacBook-Pro-Oleg.local by olegshatrov Mon Sep 12 19:59:34 2022
> [0]PETSC ERROR: Configure options --prefix=/usr/local CFLAGS="-m64 -O0 -g" CXXFLAGS="-m64 -O0 -g" FCFLAGS="-m64 -O0 -g -ffree-line-length-none" --with-mem-debug=1 --with-debugging=1 --with-mpi-dir=/usr/local/ --with-moab=true
> [0]PETSC ERROR: #1 DMCreateGlobalVector_Shell() at /Users/olegshatrov/Documents/GitHub/petsc/src/dm/impls/shell/dmshell.c:206
> [0]PETSC ERROR: #2 DMCreateGlobalVector() at /Users/olegshatrov/Documents/GitHub/petsc/src/dm/interface/dm.c:998
> [0]PETSC ERROR: #3 DMGetGlobalVector() at /Users/olegshatrov/Documents/GitHub/petsc/src/dm/interface/dmget.c:161
> [0]PETSC ERROR: #4 KSPCreateVecs() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/ksp/interface/iterativ.c:1616
> [0]PETSC ERROR: #5 KSPSetWorkVecs() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/ksp/interface/iterativ.c:1684
> [0]PETSC ERROR: #6 KSPSetUp_Chebyshev() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/ksp/impls/cheby/cheby.c:46
> [0]PETSC ERROR: #7 KSPSetUp() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/ksp/interface/itfunc.c:362
> [0]PETSC ERROR: #8 PCSetUp_MG() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/pc/impls/mg/mg.c:1189
> [0]PETSC ERROR: #9 PCSetUp() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/pc/interface/precon.c:991
> [0]PETSC ERROR: #10 KSPSetUp() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/ksp/interface/itfunc.c:401
> [0]PETSC ERROR: #11 main() at ex28.c:67
> [0]PETSC ERROR: No PETSc Option Table entries
> [0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint at mcs.anl.gov----------
> --------------------------------------------------------------------------
> 
> Somehow I thought that setting ComputeOperators and ComputeRHS will be enough..
> 
> Oleg.
> 
> 
> пн, 12 сент. 2022 г. в 19:23, Barry Smith <bsmith at petsc.dev <mailto:bsmith at petsc.dev>>:
> 
>     In PCSetUp_MG() it is creating needed vectors for each level. In order to create the vectors it needs to have a "template" of the vectors. It tries
> several ways to get such a template. 
> 
> If you have provided an vector for each level with PCMGSetRhs() it uses VecDuplicate for the needed vectors.
> 
> If you provided a matrix for each level with PCMGSetOperators() it uses the MatCreateVectors() using that matrix
> 
> If you have not provided either of those it tries DMCreateGlobalVector() for the DM associated with that level, if there is no DM it defaults to DMShell and then errors.
> 
> Since it errors this seems to indicate you did not provide an operator for each level, nor a right hand side vector. 
> 
> Please find attached a patch that may resolve the issue for.
> 
> In the petsc directory do
> patch -p1 < mg.patch
> make libs
> 
> then rerun your example. Please let us know if it resolves the problem and if not send the complete error message
> 
> Barry
> 
> 
> 
> 
>> On Sep 12, 2022, at 11:02 AM, Oleg Shatrov <shatrov.oleg.a at gmail.com <mailto:shatrov.oleg.a at gmail.com>> wrote:
>> 
>> Hello!
>> 
>> Can somebody explain to me what I am doing wrong here?
>> I took tutorial 28 from KSP folder and modified it a little in order to create manual DM interpolations and set them to PC.
>> When i run the application I receive an error:
>> 
>> [0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
>> [0]PETSC ERROR: Must call DMShellSetGlobalVector() or DMShellSetCreateGlobalVector()
>> [0]PETSC ERROR: See https://petsc.org/release/faq/ <https://petsc.org/release/faq/> for trouble shooting.
>> [0]PETSC ERROR: Petsc Development GIT revision: v3.17.3-770-gceb9926454c  GIT Date: 2022-07-15 21:35:25 +0000
>> [0]PETSC ERROR: ./a.out on a  named MacBook-Pro-Oleg.local by olegshatrov Mon Sep 12 17:53:13 2022
>> [0]PETSC ERROR: Configure options --prefix=/usr/local CFLAGS="-m64 -O0 -g" CXXFLAGS="-m64 -O0 -g" FCFLAGS="-m64 -O0 -g -ffree-line-length-none" --with-mem-debug=1 --with-debugging=1 --with-mpi-dir=/usr/local/ --with-moab=true
>> [0]PETSC ERROR: #1 DMCreateGlobalVector_Shell() at /Users/olegshatrov/Documents/GitHub/petsc/src/dm/impls/shell/dmshell.c:206
>> [0]PETSC ERROR: #2 DMCreateGlobalVector() at /Users/olegshatrov/Documents/GitHub/petsc/src/dm/interface/dm.c:998
>> [0]PETSC ERROR: #3 DMGetGlobalVector() at /Users/olegshatrov/Documents/GitHub/petsc/src/dm/interface/dmget.c:161
>> [0]PETSC ERROR: #4 KSPCreateVecs() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/ksp/interface/iterativ.c:1616
>> [0]PETSC ERROR: #5 PCSetUp_MG() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/pc/impls/mg/mg.c:1129
>> [0]PETSC ERROR: #6 PCSetUp() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/pc/interface/precon.c:991
>> [0]PETSC ERROR: #7 KSPSetUp() at /Users/olegshatrov/Documents/GitHub/petsc/src/ksp/ksp/interface/itfunc.c:401
>> [0]PETSC ERROR: #8 main() at ex28.c:67
>> [0]PETSC ERROR: No PETSc Option Table entries
>> [0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint at mcs.anl.gov <mailto:petsc-maint at mcs.anl.gov>----------
>> --------------------------------------------------------------------------
>> 
>> And this is strange, since I did not provide any Shell DM.
>> When i comment out lines with setting interpolation matrix to PCMG everything works fine:
>> <image.png>
>> 
>> I am testing on MacOS 12.3.
>> MPI: Open MPI: 4.1.4
>> gcc version 12.1.0
>> Program is compiled with mpicc ex28.c -I /usr/local/include/ -L /usr/local/lib -lpetsc
>> 
>> 
>> Thanks in advance,
>> Oleg
>> <ex28.c>
> 

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