[petsc-users] Erro in solution

[dan at ltu.se]

Hi,

I checked my code and there is no zero on the diagonal. I also modified the code
so if there is any zero on the diagonal it will be stored anyway. After this
change the problem still exists! I am not sure if I have called PETSc functions
correctly or in correct sequence. But anyway, it returns the error:

[0]PETSC ERROR: Object is in wrong state!


that and the rest of the error message is exactly as I posted before. Any idea
to solve this problem?

Thanks,

D.



Quoting Barry Smith <bsmith at mcs.anl.gov>:

> 
>    Danesh,
> 
>     Some of the PETSc solvers (like the default ILU) require that you put
> entries on all the diagonal locations of the matrix, even if they are zero.
> So you should explicitly put a 0 on the diagonal locations that have 0 and
> the issue will go away.
> 
>     Barry
> 
> On May 6, 2011, at 1:15 PM, Danesh Daroui wrote:
> 
> > 
> > Dear PETSc users,
> > 
> > I have recently started to use PETSc in our code. As the first try, I
> > assemble the matrix row by row and then put each non-zero element in
> > each row into PETSc matrix. Then I start to solve the equation. I use
> > PETSc on a multi-core machine, so I will not use MPI in my program. I
> > compiled PETSc without MPI. The PETSc parts of my code are:
> > 
> > 
> >        Mat Mp;
> >        Vec xp, bp;
> >        KSP ksp;
> >        PetscErrorCode ierr;
> > 
> >        ierr=MatCreate(PETSC_COMM_WORLD, &Mp);
> >        ierr=MatSetSizes(Mp, Msize, Msize, Msize, Msize);
> >        ierr=MatSetType(Mp, MATSEQAIJ);
> >        ierr=MatSetUp(Mp);
> > 
> >        ierr=VecCreate(PETSC_COMM_WORLD, &xp);
> >        ierr=VecSetSizes(xp, Msize, Msize);
> >        ierr=VecSetFromOptions(xp);
> > 
> >        ierr=VecCreate(PETSC_COMM_WORLD, &bp);
> >        ierr=VecSetSizes(bp, Msize, Msize);
> >        ierr=VecSetFromOptions(bp);
> > 
> > 	.
> > 	.
> > 	.
> > 
> > 	// each non zero element of row "i" and column "k" is put in 
> > 	// PETSc matrix
> > 	if (M_row[k]!=0.0)
> > 		ierr=MatSetValues(Mp, 1, &i, 1, &k, &M_row[k],
> > 					ADD_VALUES);
> > 
> > 
> > 	ierr=MatAssemblyBegin(Mp, MAT_FINAL_ASSEMBLY);
> > 	ierr=MatAssemblyEnd(Mp, MAT_FINAL_ASSEMBLY);
> > 
> > 	.
> > 	.
> > 	.
> > 
> > 	// copy right-hand-side to PETSc vector
> > 	for (int i=0; i<Msize; ++i)
> > 		VecSetValue(bp, i, b[i], INSERT_VALUES);
> > 
> > 	VecAssemblyBegin(bp);
> > 	VecAssemblyEnd(bp);
> > 
> > 	ierr=KSPCreate(PETSC_COMM_WORLD, &ksp);
> > 	ierr=KSPSetOperators(ksp, Mp, Mp, DIFFERENT_NONZERO_PATTERN);
> > 	ierr=KSPSetTolerances(ksp, 1.e-2/Msize, 1.e-50, PETSC_DEFAULT, 
> > 				PETSC_DEFAULT);
> > 	ierr=KSPSetFromOptions(ksp);
> > 	ierr=KSPSolve(ksp, bp, xp);
> > 
> > 
> > 
> > 
> > 
> > The problem is that whenever I run the code I get following output:
> > 
> > 
> > 
> > 
> > [0]PETSC ERROR: --------------------- Error Message
> > ------------------------------------
> > [0]PETSC ERROR: Object is in wrong state!
> > [0]PETSC ERROR: Matrix is missing diagonal entry 309!
> > [0]PETSC ERROR:
> > ------------------------------------------------------------------------
> > [0]PETSC ERROR: Petsc Release Version 3.1.0, Patch 8, Thu Mar 17
> > 13:37:48 CDT 2011
> > [0]PETSC ERROR: See docs/changes/index.html for recent updates.
> > [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
> > [0]PETSC ERROR: See docs/index.html for manual pages.
> > [0]PETSC ERROR:
> > ------------------------------------------------------------------------
> > [0]PETSC ERROR: Unknown Name on a linux-gnu named linux-sclt.site by dan
> > Fri May  6 19:34:19 2011
> > [0]PETSC ERROR: Libraries linked
> > from /home/danesh/petsc-3.1-p8/linux-gnu-intel/lib
> > [0]PETSC ERROR: Configure run at Fri May  6 15:50:26 2011
> > [0]PETSC ERROR: Configure options PETSC_ARCH=linux-gnu-intel
> > --with-scalar-type=complex --with-clanguage=c++ --with-mpi=0
> > --with-cc=icc --with-fc=gfortran --with-cxx=icpc
> > --with-blas-lapack-dir=/home/danesh/intel/mkl/lib/intel64/
> > [0]PETSC ERROR:
> > ------------------------------------------------------------------------
> > [0]PETSC ERROR: MatILUFactorSymbolic_SeqAIJ_ilu0() line 1627 in
> > src/mat/impls/aij/seq/aijfact.c
> > [0]PETSC ERROR: MatILUFactorSymbolic_SeqAIJ() line 1731 in
> > src/mat/impls/aij/seq/aijfact.c
> > [0]PETSC ERROR: MatILUFactorSymbolic() line 5464 in
> > src/mat/interface/matrix.c
> > [0]PETSC ERROR: PCSetUp_ILU() line 204 in
> > src/ksp/pc/impls/factor/ilu/ilu.c
> > [0]PETSC ERROR: PCSetUp() line 795 in src/ksp/pc/interface/precon.c
> > [0]PETSC ERROR: KSPSetUp() line 237 in src/ksp/ksp/interface/itfunc.c
> > [0]PETSC ERROR: KSPSolve() line 353 in src/ksp/ksp/interface/itfunc.c
> > 
> > 
> > 
> > I am sure that the matrix is correct and the system is not singular
> > because the system can be solved using LAPACK's direct solver. I
> > probably format the PETSc matrix incorrectly or some PETSc parameters
> > are wrong. I would appreciate if you give me any clue about possible
> > problem(s).
> > 
> > Regards,
> > 
> > Danesh
> > 
> > 
> 
> 
>