[petsc-users] On PCFIELDSPLIT and its implementation

[Matthew Knepley]

On Wed, Nov 9, 2022 at 7:57 AM Edoardo alinovi <edoardo.alinovi at gmail.com>
wrote:

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

I think you are right. Those should start from 1. However, your ISes do not
seem to cover
the whole matrix. Can you start with a very small problem so that you can
print them to
the screen?

  Thanks,

     Matt


> 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/>
>>>
>>

-- 
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/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20221109/b1ee7bad/attachment-0001.html>