[petsc-users] Floating point exception

[Danyang Su]

Hi All,

One of my case crashes because of floating point exception when using 4 
processors, as shown below. But if I run this case with 1 processor, it 
works fine. I have tested the codes with around 100 cases up to 768 
processors, all other cases work fine. I just wonder if this kind of 
error is caused because of NaN in jacobi matrix, RHS or preconditioner? 
I can check all the entries of jacobi matrix to see if the value is 
valid, but this seems not a good idea as it takes a long time to reach 
this point. If I restart the simulation from a specified time (e.g., 
7.685 in this case), then the error does not occur.

Would you please give me any suggestion on debugging this case?

Thanks and Regards,

Danyang


  timestep:    2730 time: 7.665E+00 years   delt: 1.000E-02 years iter:  
1 max.sia: 0.000E+00 tol.sia: 0.000E+00
  timestep:    2731 time: 7.675E+00 years   delt: 1.000E-02 years iter:  
1 max.sia: 0.000E+00 tol.sia: 0.000E+00
  timestep:    2732 time: 7.685E+00 years   delt: 1.000E-02 years iter:  
1 max.sia: 0.000E+00 tol.sia: 0.000E+00
  timestep:    2733 time: 7.695E+00 years   delt: 1.000E-02 years iter:  
1 max.sia: 0.000E+00 tol.sia: 0.000E+00
  timestep:    2734 time: 7.705E+00 years   delt: 1.000E-02 years iter:  
1 max.sia: 0.000E+00 tol.sia: 0.000E+00
  Reduce time step for reactive transport
  timestep:    2734 time: 7.700E+00 years   delt: 5.000E-03 years iter:  
1 max.sia: 0.000E+00 tol.sia: 0.000E+00
  Reduce time step for reactive transport
  timestep:    2734 time: 7.697E+00 years   delt: 2.500E-03 years iter:  
1 max.sia: 0.000E+00 tol.sia: 0.000E+00
[1]PETSC ERROR: --------------------- Error Message 
--------------------------------------------------------------
[1]PETSC ERROR: Floating point exception
[2]PETSC ERROR: --------------------- Error Message 
--------------------------------------------------------------
[2]PETSC ERROR: Floating point exception
[2]PETSC ERROR: Vec entry at local location 0 is not-a-number or 
infinite at end of function: Parameter number 3
[2]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html 
for trouble shooting.
[2]PETSC ERROR: Petsc Release Version 3.5.2, Sep, 08, 2014
[2]PETSC ERROR: [1]PETSC ERROR: Vec entry at local location 0 is 
not-a-number or infinite at end of function: Parameter number 3
[1]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html 
for trouble shooting.
[1]PETSC ERROR: Petsc Release Version 3.5.2, Sep, 08, 2014
[1]PETSC ERROR: ../min3p_thcm_petsc_dbg on a linux-gnu-dbg named nwmop 
by dsu Thu Apr 23 15:38:52 2015
[1]PETSC ERROR: Configure options PETSC_ARCH=linux-gnu-dbg --with-cc=gcc 
--with-cxx=g++ --with-fc=gfortran --download-fblaslapack 
--download-mpich --download-mumps --download-hypre 
--download-superlu_dist --download-metis --download-parmetis 
--download-scalapack
[1]PETSC ERROR: #1 VecValidValues() line 34 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/vec/vec/interface/rvector.c
../min3p_thcm_petsc_dbg on a linux-gnu-dbg named nwmop by dsu Thu Apr 23 
15:38:52 2015
[2]PETSC ERROR: Configure options PETSC_ARCH=linux-gnu-dbg --with-cc=gcc 
--with-cxx=g++ --with-fc=gfortran --download-fblaslapack 
--download-mpich --download-mumps --download-hypre 
--download-superlu_dist --download-metis --download-parmetis 
--download-scalapack
[2]PETSC ERROR: #1 VecValidValues() line 34 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/vec/vec/interface/rvector.c
[2]PETSC ERROR: [1]PETSC ERROR: #2 PCApply() line 442 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/ksp/pc/interface/precon.c
[1]PETSC ERROR: #2 PCApply() line 442 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/ksp/pc/interface/precon.c
[2]PETSC ERROR: #3 KSP_PCApply() line 230 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/include/petsc-private/kspimpl.h
#3 KSP_PCApply() line 230 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/include/petsc-private/kspimpl.h
[1]PETSC ERROR: #4 KSPInitialResidual() line 63 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/ksp/ksp/interface/itres.c
[2]PETSC ERROR: #4 KSPInitialResidual() line 63 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/ksp/ksp/interface/itres.c
[1]PETSC ERROR: #5 KSPSolve_GMRES() line 234 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/ksp/ksp/impls/gmres/gmres.c
[2]PETSC ERROR: #5 KSPSolve_GMRES() line 234 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/ksp/ksp/impls/gmres/gmres.c
[2]PETSC ERROR: #6 KSPSolve() line 459 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/ksp/ksp/interface/itfunc.c
[1]PETSC ERROR: #6 KSPSolve() line 459 in 
/home/dsu/Soft/PETSc/petsc-3.5.2/src/ksp/ksp/interface/itfunc.c
^C[mpiexec at nwmop] Sending Ctrl-C to processes as requested
[mpiexec at nwmop] Press Ctrl-C again to force abort