[petsc-users] Is PCFactorSetZeroPivot() effective?

[Jozsef Bakosi]

On 05.31.2012 15:12, Jed Brown wrote:
> On Thu, May 31, 2012 at 3:08 PM, Jozsef Bakosi <jbakosi at lanl.gov> wrote:
> 
> > Using -sub_pc_factor_zeropivot does not seem to make any difference.
> >
> 
> Run with -ksp_view and send the output. Also send the FULL error message
> when it finds a zero pivot.

I don't seem to find any additional output from -ksp_view. Am I doing
something wrong when I simply pass -ksp_view to the exectuable?

The full file would be 48M, here is a snippet that keeps coming from all
cores:

[44]PETSC ERROR: --------------------- Error Message -----------------------------------
[44]PETSC ERROR: Detected zero pivot in LU factorization see
http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#ZeroPivot!
[44]PETSC ERROR: Zero pivot row 537 value 9.36276e-13 tolerance 1e-12!
[44]PETSC ERROR:
------------------------------------------------------------------------
[44]PETSC ERROR: Petsc Release Version 3.1.0, Patch 8, Thu Mar 17 13:37:48 CDT 2011
[44]PETSC ERROR: See docs/changes/index.html for recent updates.
[44]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
[44]PETSC ERROR: See docs/index.html for manual pages.
[44]PETSC ERROR:
------------------------------------------------------------------------
[44]PETSC ERROR: Unknown Name on a conejo-gn named mu0455.localdomain by jbakosi Thu May 31 14:26:36 2012
[44]PETSC ERROR: Libraries linked from /scratch3/jbakosi/code/hydra/tpl/gnu/lib
[44]PETSC ERROR: Configure run at Mon May 21 09:35:16 2012
[44]PETSC ERROR: Configure options PETSC_DIR=/tmp/temp/petsc-3.1-p8 PETSC_ARCH=conejo-gnu-opt --prefix=/scratch3/jbakosi/code/hydra/tpl/gnu --with-clanguage=c++ --with-x=false --with-x11=false --download-ml=/scratch3/jbakosi/code/hydra/tpl/tarballs/ml-6.2.tar.gz --with-debugging=0 -COPTFLAGS=-O3 -CXXOPTFLAGS=-O3 -FOPTFLAGS=-O3 -FFLAGS=-ffree-line-length-none
[44]PETSC ERROR:
------------------------------------------------------------------------
[44]PETSC ERROR: MatLUFactorNumeric_SeqAIJ() line 574 in src/mat/impls/aij/seq/aijfact.c
[44]PETSC ERROR: MatLUFactorNumeric() line 2587 in src/mat/interface/matrix.c
[44]PETSC ERROR: PCSetUp_LU() line 158 in src/ksp/pc/impls/factor/lu/lu.c
[44]PETSC ERROR: PCSetUp() line 795 in src/ksp/pc/interface/precon.c
[44]PETSC ERROR: KSPSetUp() line 237 in src/ksp/ksp/interface/itfunc.c
[44]PETSC ERROR: PCSetUp_Redundant() line 179 in src/ksp/pc/impls/redundant/redundant.c
[44]PETSC ERROR: PCSetUp() line 795 in src/ksp/pc/interface/precon.c
[44]PETSC ERROR: KSPSetUp() line 237 in src/ksp/ksp/interface/itfunc.c
[44]PETSC ERROR: PCSetUp_MG() line 602 in src/ksp/pc/impls/mg/mg.c
[44]PETSC ERROR: PCSetUp_ML() line 668 in src/ksp/pc/impls/ml/ml.c
[44]PETSC ERROR: PCSetUp() line 795 in src/ksp/pc/interface/precon.c
[44]PETSC ERROR: KSPSetUp() line 237 in src/ksp/ksp/interface/itfunc.c
[44]PETSC ERROR: User provided function() line 275 in "unknowndirectory/"/scratch3/jbakosi/code/hydra/src/LinearAlgebra/PetscSolver.C

> What discretization are you using?

Straightforward Galerkin FEM Poisson solver.

Jozsef