[petsc-users] Problem with least squares commutators(LSC)

[keguoyi]

Dear Users,

The following is the full error message. Thank you so much!

 *************** Linear iteration 1 ***********
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR: Object is in wrong state
[0]PETSC ERROR: Matrix is missing diagonal entry 0
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.6.1, unknown
[0]PETSC ERROR: ./PCFieldSplit_ex13 on a arch-linux2-cxx-opt named linux-394h by coyigg Wed Feb  3 14:57:21 2016
[0]PETSC
 ERROR: Configure options --with-clanguage=cxx --with-debugging=0 
--download-fblaslapack=1 --download-hdf5=1 --download-openmpi=1 
--download-metis=1 --download-parmetis=1 --with-shared-libraries=1 
--with-cc=gcc --with-fc=gfortran --with-cxx=g++ --download-blacs=1 
--download-scalapack=1 --download-mumps=1
[0]PETSC ERROR: #1 MatILUFactorSymbolic_SeqAIJ() line 1729 in /home/eaulisa/software/petsc/src/mat/impls/aij/seq/aijfact.c
[0]PETSC ERROR: #2 MatILUFactorSymbolic() line 6457 in /home/eaulisa/software/petsc/src/mat/interface/matrix.c
[0]PETSC ERROR: #3 PCSetUp_ILU() line 204 in /home/eaulisa/software/petsc/src/ksp/pc/impls/factor/ilu/ilu.c
[0]PETSC ERROR: #4 PCSetUp() line 983 in /home/eaulisa/software/petsc/src/ksp/pc/interface/precon.c
[0]PETSC ERROR: #5 KSPSetUp() line 332 in /home/eaulisa/software/petsc/src/ksp/ksp/interface/itfunc.c
[0]PETSC ERROR: #6 KSPSolve() line 546 in /home/eaulisa/software/petsc/src/ksp/ksp/interface/itfunc.c
[0]PETSC ERROR: #7 PCApply_LSC() line 83 in /home/eaulisa/software/petsc/src/ksp/pc/impls/lsc/lsc.c
[0]PETSC ERROR: #8 PCApply() line 483 in /home/eaulisa/software/petsc/src/ksp/pc/interface/precon.c
[0]PETSC ERROR: #9 KSP_PCApply() line 242 in /home/eaulisa/software/petsc/include/petsc/private/kspimpl.h
[0]PETSC ERROR: #10 KSPSolve_PREONLY() line 26 in /home/eaulisa/software/petsc/src/ksp/ksp/impls/preonly/preonly.c
[0]PETSC ERROR: #11 KSPSolve() line 604 in /home/eaulisa/software/petsc/src/ksp/ksp/interface/itfunc.c
[0]PETSC ERROR: #12 PCApply_FieldSplit_Schur() line 874 in /home/eaulisa/software/petsc/src/ksp/pc/impls/fieldsplit/fieldsplit.c
[0]PETSC ERROR: #13 PCApply() line 483 in /home/eaulisa/software/petsc/src/ksp/pc/interface/precon.c
[0]PETSC ERROR: #14 KSP_PCApply() line 242 in /home/eaulisa/software/petsc/include/petsc/private/kspimpl.h
[0]PETSC ERROR: #15 KSPInitialResidual() line 63 in /home/eaulisa/software/petsc/src/ksp/ksp/interface/itres.c
[0]PETSC ERROR: #16 KSPSolve_GMRES() line 235 in /home/eaulisa/software/petsc/src/ksp/ksp/impls/gmres/gmres.c
[0]PETSC ERROR: #17 KSPSolve() line 604 in /home/eaulisa/software/petsc/src/ksp/ksp/interface/itfunc.c
[0]PETSC ERROR: #18 PCMGMCycle_Private() line 19 in /home/eaulisa/software/petsc/src/ksp/pc/impls/mg/mg.c
[0]PETSC ERROR: #19 PCApply_MG() line 340 in /home/eaulisa/software/petsc/src/ksp/pc/impls/mg/mg.c
[0]PETSC ERROR: #20 PCApply() line 483 in /home/eaulisa/software/petsc/src/ksp/pc/interface/precon.c
[0]PETSC ERROR: #21 KSPSolve() line 582 in /home/eaulisa/software/petsc/src/ksp/ksp/interface/itfunc.c
 *************** MG linear solver time:    0.002
 *************** Number of outer ksp solver iterations = 0
 *************** Convergence reason = 0
 *************** Residual norm =          0
 *************** Level Max 2  Linear Res  L2norm U = 4.033131e-02
 *************** Level Max 2  Linear Res  L2norm V = 5.330749e-02
 *************** Level Max 2  Linear Res  L2norm P = 1.396813e-01


> Subject: Re: [petsc-users] Problem with least squares commutators(LSC)
> From: bsmith at mcs.anl.gov
> Date: Wed, 3 Feb 2016 22:26:42 -0600
> CC: petsc-users at mcs.anl.gov
> To: coyigg at hotmail.com
> 
> 
>   We'd need the full error message to determine what is happening.
> 
>   But note that since the lower right block is all 0 any attempt to use a factorization of that inside a preconditioner will fail with zero pivot. 
> 
> 
> > On Feb 2, 2016, at 10:40 PM, keguoyi <coyigg at hotmail.com> wrote:
> > 
> > Dear PETSc users,
> > 
> > This is Guoyi Ke, a graduate student of Texas Tech University. I have a 2D Navier Stokes problem that has block matrices: J=[F    B^T; B    0]. I use Schur complement preconditioner for block J. The code was set as:
> > 
> >       PCFieldSplitSetType( pc, PC_COMPOSITE_SCHUR );
> >       PCFieldSplitSetSchurFactType(pc, PC_FIELDSPLIT_SCHUR_FACT_LOWER);
> >       PCFieldSplitSetSchurPre(pc,PC_FIELDSPLIT_SCHUR_PRE_SELFP,NULL);
> > 
> > For both velocity block (fieldsplit: 0) and pressure block (fieldsplit: 1) , we set the KSP as KSPPREONLY and PC as PCILU. For this case, it works fine for us. 
> > However, in order to use LSC we change the code as:
> > 
> >       PCFieldSplitSetType( pc, PC_COMPOSITE_SCHUR );
> >       PCFieldSplitSetSchurFactType(pc, PC_FIELDSPLIT_SCHUR_FACT_LOWER);
> >       PCFieldSplitSetSchurPre(pc,PC_FIELDSPLIT_SCHUR_PRE_SELF,NULL);
> > 
> > We keep the same setup for velocity block (fieldsplit: 0) as above. For pressure block (fieldsplit: 1), we set the KSP as KSPGMRES and PC as PCLSU. I got the following errors:
> > 
> > [0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
> > [0]PETSC ERROR: Object is in wrong state
> > [0]PETSC ERROR: Matrix is missing diagonal entry 0
> > 
> > 
> > Any suggestion and help will be highly appreciated. Thank you so much!
> > 
> > Best,
> > Guoyi 
> 
 		 	   		  
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