[petsc-users] Matrix is missing diagonal entry

[Kong, Fande]

Thanks, Hong and Jed.

I am going to explicitly add a few zeros into the matrix.


Regards,

Fande,

On Tue, Oct 18, 2016 at 9:46 AM, Hong <hzhang at mcs.anl.gov> wrote:

> You need set 0.0 to the diagonals.
> Diagonal storage is used in PETSc library.
>
> Hong
>
>
> On Tue, Oct 18, 2016 at 10:11 AM, Kong, Fande <fande.kong at inl.gov> wrote:
>
>> Hi Developers,
>>
>> Any reason to force users provide a matrix which does not miss any
>> diagonal entries when using a LU-type solver?
>>
>> Sometime, it is impossible to have all diagonal entries in a matrix, that
>> is, the matrix has to miss some diagonal entries. For example, there is a
>> saddle-point matrix from the discretization of incomprehensible equations,
>> and the lower part of the matrix is a zero block. The matrix usually looks
>> like:
>>
>> | A   B^T  |
>> | B    0     |
>>
>>
>>
>>
>>
>> [56]PETSC ERROR: Object is in wrong state
>> [56]PETSC ERROR: Matrix is missing diagonal entry 33
>> [56]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html
>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mcs.anl.gov_petsc_documentation_faq.html&d=CwMFaQ&c=54IZrppPQZKX9mLzcGdPfFD1hxrcB__aEkJFOKJFd00&r=DUUt3SRGI0_JgtNaS3udV68GRkgV4ts7XKfj2opmiCY&m=rGGzwQ3YeqAfah8-uPSZwxM_Rf91WEU1UKQesi8UMi0&s=MvjUyc6lhioQlvGYpWhxtc8rWrFV4gbQjYOmBYlIyiA&e=>
>> for trouble shooting.
>> [56]PETSC ERROR: Petsc Release Version 3.6.2, unknown
>> [56]PETSC ERROR: ./fluid on a arch-linux2-cxx-opt named ys0755 by fandek
>> Mon Oct 17 17:06:08 2016
>> [56]PETSC ERROR: Configure options --with-clanguage=cxx
>> --with-shared-libraries=1 --download-fblaslapack=1 --with-mpi=1
>> --download-parmetis=1 --download-metis=1 --with-netcdf=1
>> --download-exodusii=1 --with-hdf5=1 --with-debugging=no --with-c2html=0
>> --with-64-bit-indices=1 --download-hypre=1 --download-superlu_dist=1
>> [56]PETSC ERROR: #1 MatILUFactorSymbolic_SeqAIJ() line 1729 in
>> /petsc_installed/petsc/src/mat/impls/aij/seq/aijfact.c
>> [56]PETSC ERROR: #2 MatILUFactorSymbolic() line 6457 in
>> /petsc_installed/petsc/src/mat/interface/matrix.c
>> [56]PETSC ERROR: #3 PCSetUp_ILU() line 204 in
>> /petsc_installed/petsc/src/ksp/pc/impls/factor/ilu/ilu.c
>> [56]PETSC ERROR: #4 PCSetUp() line 983 in /petsc_installed/petsc/src/ksp
>> /pc/interface/precon.c
>> [56]PETSC ERROR: #5 KSPSetUp() line 332 in /petsc_installed/petsc/src/ksp
>> /ksp/interface/itfunc.c
>> [56]PETSC ERROR: #6 PCSetUpOnBlocks_ASM() line 405 in
>> /petsc_installed/petsc/src/ksp/pc/impls/asm/asm.c
>> [56]PETSC ERROR: #7 PCSetUpOnBlocks() line 1016 in
>> /petsc_installed/petsc/src/ksp/pc/interface/precon.c
>> [56]PETSC ERROR: #8 KSPSetUpOnBlocks() line 167 in
>> /petsc_installed/petsc/src/ksp/ksp/interface/itfunc.c
>> [56]PETSC ERROR: #9 KSPSolve() line 552 in /petsc_installed/petsc/src/ksp
>> /ksp/interface/itfunc.c
>> [56]PETSC ERROR: #10 PCApply_LSC() line 83 in
>> /petsc_installed/petsc/src/ksp/pc/impls/lsc/lsc.c
>> [56]PETSC ERROR: #11 PCApply() line 483 in /petsc_installed/petsc/src/ksp
>> /pc/interface/precon.c
>> [56]PETSC ERROR: #12 KSP_PCApply() line 242 in
>> /petsc_installed/petsc/include/petsc/private/kspimpl.h
>> [56]PETSC ERROR: #13 KSPSolve_PREONLY() line 26 in
>> /petsc_installed/petsc/src/ksp/ksp/impls/preonly/preonly.c
>> [56]PETSC ERROR: #14 KSPSolve() line 604 in /petsc_installed/petsc/src/ksp
>> /ksp/interface/itfunc.c
>> [56]PETSC ERROR: #15 PCApply_FieldSplit_Schur() line 904 in
>> /petsc_installed/petsc/src/ksp/pc/impls/fieldsplit/fieldsplit.c
>> [56]PETSC ERROR: #16 PCApply() line 483 in /petsc_installed/petsc/src/ksp
>> /pc/interface/precon.c
>> [56]PETSC ERROR: #17 KSP_PCApply() line 242 in
>> /petsc_installed/petsc/include/petsc/private/kspimpl.h
>> [56]PETSC ERROR: #18 KSPInitialResidual() line 63 in
>> /petsc_installed/petsc/src/ksp/ksp/interface/itres.c
>> [56]PETSC ERROR: #19 KSPSolve_GMRES() line 235 in
>> /petsc_installed/petsc/src/ksp/ksp/impls/gmres/gmres.c
>> [56]PETSC ERROR: #20 KSPSolve() line 604 in /petsc_installed/petsc/src/ksp
>> /ksp/interface/itfunc.c
>> [56]PETSC ERROR: #21 SNESSolve_NEWTONLS() line 233 in
>> /petsc_installed/petsc/src/snes/impls/ls/ls.c
>> [56]PETSC ERROR: #22 SNESSolve() line 3906 in
>> /petsc_installed/petsc/src/snes/interface/snes.c
>>
>>
>> Thanks,
>>
>> Fande Kong,
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20161018/cc2e4db6/attachment-0001.html>