[petsc-users] How to debug PETSc error

[TAY wee-beng]

Hi,

I have a CFD code which gives an error when solving the momentum eqn at 
time step = 1109. Using KSPGetConvergedReason give < 0 using optimized 
build.

I retry using debug build and it gives the error below. I sent the job 
to a job scheduler on 32 procs. So what is best way to debug? Should I 
print out the matrix but it is very big since grid size is 13 million.

Thanks. Regards.

n12-10:13681] 31 more processes have sent help message 
help-mpi-btl-base.txt / btl:no-nics
[n12-10:13681] Set MCA parameter "orte_base_help_aggregate" to 0 to see 
all help / error messages
[17]PETSC ERROR: 
------------------------------------------------------------------------
[17]PETSC ERROR: Caught signal number 8 FPE: Floating Point 
Exception,probably divide by zero
[17]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
[17]PETSC ERROR: or see 
http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[17]PETSC 
ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to 
find memory corruption errors
[17]PETSC ERROR: likely location of problem given in stack below
[17]PETSC ERROR: ---------------------  Stack Frames 
------------------------------------
[17]PETSC ERROR: Note: The EXACT line numbers in the stack are not 
available,
[17]PETSC ERROR:       INSTEAD the line number of the start of the function
[17]PETSC ERROR:       is given.
[17]PETSC ERROR: [17] VecNorm_MPI line 57 
/home/wtay/Codes/petsc-3.4.4/src/vec/vec/impls/mpi/pvec2.c
[17]PETSC ERROR: [17] VecNorm line 224 
/home/wtay/Codes/petsc-3.4.4/src/vec/vec/interface/rvector.c
[17]PETSC ERROR: [17] KSPSolve_BCGS line 39 
/home/wtay/Codes/petsc-3.4.4/src/ksp/ksp/impls/bcgs/bcgs.c
[17]PETSC ERROR: [17] KSPSolve line 356 
/home/wtay/Codes/petsc-3.4.4/src/ksp/ksp/interface/itfunc.c

-- 
Thank you

Yours sincerely,

TAY wee-beng