[petsc-users] On PCFIELDSPLIT and its implementation

[Edoardo alinovi]

To be clear,

You are suggesting to use ufields(0)=0, ufields(1)=1 and so on?

Il Mer 9 Nov 2022, 13:54 Edoardo alinovi <edoardo.alinovi at gmail.com> ha
scritto:

> Even in the fortran interface?
>
> Il Mer 9 Nov 2022, 13:52 Matthew Knepley <knepley at gmail.com> ha scritto:
>
>> Fields are numbered from 0.
>>
>>   Thanks,
>>
>>      Matt
>>
>> On Wed, Nov 9, 2022 at 2:20 AM Edoardo alinovi <edoardo.alinovi at gmail.com>
>> wrote:
>>
>>> Hello guys,
>>>
>>> I am getting this error while using fieldsplit:
>>>
>>> [3]PETSC ERROR: --------------------- Error Message
>>> --------------------------------------------------------------
>>>
>>> *[3]PETSC ERROR: Nonconforming object sizes[3]PETSC ERROR: Local column
>>> sizes 6132 do not add up to total number of columns 9200*
>>> [3]PETSC ERROR: See https://petsc.org/release/faq/ for trouble shooting.
>>> [3]PETSC ERROR: Petsc Development GIT revision: v3.18.1-191-g32ed6ae2ff2
>>>  GIT Date: 2022-11-08 12:22:17 -0500
>>> [3]PETSC ERROR: flubio_coupled on a gnu named alienware by edo Wed Nov
>>>  9 08:16:29 2022
>>> [3]PETSC ERROR: Configure options PETSC_ARCH=gnu FOPTFLAGS=-O3
>>> COPTFLAGS=-O3 CXXOPTFLAGS=-O3 -with-debugging=no -download-fblaslapack=1
>>> -download-superlu_dist -download-mumps -download-hypre -download-metis
>>> -download-parmetis -download-scalapack -download-ml -download-slepc
>>> -download-hpddm -download-cmake
>>> -with-mpi-dir=/home/edo/software/openmpi-4.1.1/build/
>>> [3]PETSC ERROR: #1 MatCreateSubMatrix_MPIBAIJ_Private() at
>>> /home/edo/software/petsc/src/mat/impls/baij/mpi/mpibaij.c:1987
>>> [3]PETSC ERROR: #2 MatCreateSubMatrix_MPIBAIJ() at
>>> /home/edo/software/petsc/src/mat/impls/baij/mpi/mpibaij.c:1911
>>> [3]PETSC ERROR: #3 MatCreateSubMatrix() at
>>> /home/edo/software/petsc/src/mat/interface/matrix.c:8340
>>> [3]PETSC ERROR: #4 PCSetUp_FieldSplit() at
>>> /home/edo/software/petsc/src/ksp/pc/impls/fieldsplit/fieldsplit.c:657
>>> [3]PETSC ERROR: #5 PCSetUp() at
>>> /home/edo/software/petsc/src/ksp/pc/interface/precon.c:994
>>> [3]PETSC ERROR: #6 KSPSetUp() at
>>> /home/edo/software/petsc/src/ksp/ksp/interface/itfunc.c:406
>>> [3]PETSC ERROR: #7 KSPSolve_Private() at
>>> /home/edo/software/petsc/src/ksp/ksp/interface/itfunc.c:825
>>> [3]PETSC ERROR: #8 KSPSolve() at
>>> /home/edo/software/petsc/src/ksp/ksp/interface/itfunc.c:1071
>>>
>>> Do you have any ideas? Probably something missing in my brief
>>> implementation here:
>>>
>>>
>>>
>>>
>>> *            call PCSetType(mypc, PCFIELDSPLIT, ierr)              call
>>> PCFieldSplitSetBlockSize(mypc, 4-bdim, ierr)           *
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> *            !2D, 3x3 block            if(bdim==1) then
>>> ufields(1) = 0                ufields(2) = 1                pfields(1) = 2
>>>               call PCFieldSplitSetFields(mypc, "u", 2, ufields, ufields,
>>> ierr)                call PCFieldSplitSetFields(mypc, "p", 1, pfields,
>>> pfields, ierr)             ! 3D 4x4 block            else
>>> ufields(1) = 0                ufields(2) = 1                ufields(3) = 2
>>>               pfields(1) = 3                call
>>> PCFieldSplitSetFields(mypc, "u", 3, ufields, ufields, ierr)
>>> call PCFieldSplitSetFields(mypc, "p", 1, pfields, pfields, ierr)
>>> endif                         ! Field split type ADDITIVE, MULTIPLICATIVE
>>> (default), SYMMETRIC_MULTIPLICATIVE, SPECIAL, SCHUR            call
>>> PCFieldSplitSetType(mypc, PC_COMPOSITE_SCHUR, ierr)*
>>>
>>> Thanks for the help!
>>>
>>
>>
>> --
>> 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
>>
>> https://www.cse.buffalo.edu/~knepley/
>> <http://www.cse.buffalo.edu/~knepley/>
>>
>
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