[petsc-users] VecValidValues() reports NaN found

[Matthew Knepley]

On Mon, May 5, 2014 at 7:25 AM, linjing bo <francium87 at hotmail.com> wrote:

>  Hi, I'm trying to use PETSc's ksp method to solve a linear system. When
> running, Error is reported by VecValidValues() that NaN or Inf is found
> with error message listed below
>
>
> [3]PETSC ERROR: --------------------- Error Message
> ------------------------------------
> [3]PETSC ERROR: Floating point
> exception!
> [3]PETSC ERROR: Vec entry at local location 0 is not-a-number or infinite
> at beginning of function: Parameter number
> 2!
>
> [3]PETSC ERROR:
> ------------------------------------------------------------------------
>
> [3]PETSC ERROR: Petsc Release Version 3.4.4, Mar, 13,
> 2014
> [3]PETSC ERROR: See docs/changes/index.html for recent
> updates.
> [3]PETSC ERROR: See docs/faq.html for hints about trouble
> shooting.
> [3]PETSC ERROR: See docs/index.html for manual
> pages.
> [3]PETSC ERROR:
> ------------------------------------------------------------------------
>
> [3]PETSC ERROR: ./gtc on a arch-linux2-c-debug named node2.indac.info by
> jlin Mon May  5 20:03:20
> 2014
>
> [3]PETSC ERROR: Libraries linked from
> /opt/sfw/petsc/3.4.4/intel/openmpi/lib
> [3]PETSC ERROR: Configure run at Sat Apr 26 20:19:41
> 2014
> [3]PETSC ERROR: Configure options
> --prefix=/opt/sfw/petsc/3.4.4/intel/openmpi
> --with-mpi-dir=/opt/sfw/openmpi/1.6.3/intel
> --with-blas-lapack-dir=/opt/sfw/intel/composer_xe_2011_sp1.7.256/mkl/lib/intel64
> --with-mpiexec=mpiexec
>
> [3]PETSC ERROR:
> ------------------------------------------------------------------------
>
> [3]PETSC ERROR: VecValidValues() line 28 in
> /tmp/petsc-3.4.4/src/vec/vec/interface/rvector.c
>

It looks like the vector after preconditioner application is bad. What is
the preconditioner?

  Matt


>
> [3]PETSC ERROR: PCApply() line 436 in
> /tmp/petsc-3.4.4/src/ksp/pc/interface/precon.c
> [3]PETSC ERROR: KSP_PCApply() line 227 in
> /tmp/petsc-3.4.4/include/petsc-private/kspimpl.h
> [3]PETSC ERROR: KSPInitialResidual() line 64 in
> /tmp/petsc-3.4.4/src/ksp/ksp/interface/itres.c
> [3]PETSC ERROR: KSPSolve_GMRES() line 239 in
> /tmp/petsc-3.4.4/src/ksp/ksp/impls/gmres/gmres.c
> [3]PETSC ERROR: KSPSolve() line 441 in
> /tmp/petsc-3.4.4/src/ksp/ksp/interface/itfunc.c
>
>
> After read the source code shown by backtrack informations, I realize the
> problem is in the right hand side vector. So I make a trial of set right
> hand side vector to ONE by VecSet, But the program still shows error
> message above, and using VecView or VecGetValue to investigate the first
> value of rhs vec shows the value is 1.0 as I set it to. Hope I clearly
> describe the problem. The code related is listed below
>
> ---------------------------Solver section--------------------------
>
>   call VecSet( pet_bp_b, one, ierr)
>
>   vecidx=[0,1]
>   call VecGetValues( pet_bp_b, 2, vecidx, first, ierr)
>   write(*,*) ' first two values ', first(1), first(2)
>
>   call KSPSetInitialGuessNonzero(solver_bp,Petsc_True,ierr)
>   call KSPSolve(solver_bp,pet_bp_b,pet_bp_x,ierr)
>   call KSPView(solver_bp, PETSC_VIEWER_STDOUT_SELF,ierr)
>   CHKERRQ(ierr)
>
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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