[petsc-users] Matrix is missing diagonal entry

[Kong, Fande]

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
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,
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