[petsc-users] Floating point exception

Danyang Su danyang.su at gmail.com
Fri Apr 24 15:54:18 CDT 2015 

On 15-04-24 01:23 PM, Satish Balay wrote:
>   c           4   1.0976214263087059E-067
>
> I don't think this number can be stored in a real*4.
>
> Satish
Thanks, Satish. It is caused by this number.
>
> On Fri, 24 Apr 2015, Danyang Su wrote:
>
>>
>> On 15-04-24 11:12 AM, Barry Smith wrote:
>>>> On Apr 24, 2015, at 1:05 PM, Danyang Su <danyang.su at gmail.com> wrote:
>>>>
>>>> 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?
>>>      Yes, almost for sure it is one of these places.
>>>
>>>      First run the bad case with -fp_trap  if all goes well you'll see the
>>> function where the FPE is generated. Then run also with -start_in_debugger
>>> and
>>> type cont in all four debugger windows. When the FPE happens the debugger
>>> should stop showing exactly where the FPE happens.
>>>
>>>     Barry
>> Hi Barry,
>>
>> If run with -fp_trap -start_in_debugger, I got the following error
>>
>> [0]PETSC ERROR: *** unknown floating point error occurred ***
>> [0]PETSC ERROR: The specific exception can be determined by running in a
>> debugger.  When the
>> [0]PETSC ERROR: debugger traps the signal, the exception can be found with
>> fetestexcept(0x3d)
>> [0]PETSC ERROR: where the result is a bitwise OR of the following flags:
>> [0]PETSC ERROR: FE_INVALID=0x1 FE_DIVBYZERO=0x4 FE_OVERFLOW=0x8
>> FE_UNDERFLOW=0x10 FE_INEXACT=0x20
>> [0]PETSC ERROR: Try option -start_in_debugger
>> [0]PETSC ERROR: likely location of problem given in stack below
>> [0]PETSC ERROR: ---------------------  Stack Frames
>> ------------------------------------
>> [0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,
>> [0]PETSC ERROR:       INSTEAD the line number of the start of the function
>> [0]PETSC ERROR:       is given.
>> [0]PETSC ERROR: [0] PetscDefaultFPTrap line 379
>> /home/dsu/Soft/PETSc/petsc-3.5.2/src/sys/error/fp.c
>> [0]PETSC ERROR: User provided function() line 0 in Unknown file trapped
>> floating point error
>>
>> Program received signal SIGABRT: Process abort signal.
>>
>> Backtrace for this error:
>> #0  0x7F4FEAB1C7D7
>> #1  0x7F4FEAB1CDDE
>> #2  0x7F4FE9E1AD3F
>> #3  0x7F4FE9E1ACC9
>> #4  0x7F4FE9E1E0D7
>> #5  0x7F4FEB0B6DCB
>> #6  0x7F4FEB0B1825
>> #7  0x7F4FEB0B817F
>> #8  0x7F4FE9E1AD3F
>> #9  0x6972C8 in tprfrtlc_ at tprfrtlc.F90:2393 (discriminator 3)
>> #10  0x4C6C87 in gcreact_ at gcreact.F90:678
>> #11  0x707E19 in initicrt_ at initicrt.F90:589
>> #12  0x4F42D0 in initprob_ at initprob.F90:430
>> #13  0x5AAF72 in driver_pc at driver_pc.F90:438
>>
>> I checked the code at  tprfrtlc.F90:2393,
>>
>>          realbuffer_gb(1:nvars) = (/time,(c(ic),ic=1,nc-1),     &
>>                                     (cx(ix),ix=1,nxout)/)
>>
>> All the values (time, c, cx) are reasonable, as shown below. The only
>> possibility is that realbuffer_gb is in declared as real*4 if using sing
>> precision output while time, c, cx are declared in real*8. I have a lot of
>> similar data conversion from real*8 to real*4 output, other code does not
>> return error.
>>
>>   time   0.0000000000000000
>>   c           1   9.9999999999999995E-008
>>   c           2   3.1555251077549618E-003
>>   c           3   7.1657814842179362E-008
>>   c           4   1.0976214263087059E-067
>>   c           5   5.2879822292305797E-004
>>   c           6   9.9999999999999964E-005
>>   c           7   6.4055731968811337E-005
>>   c           8   3.4607572892578404E-020
>>   cx           1   3.4376650636008101E-005
>>   cx           2   7.3989678854017763E-012
>>   cx           3   9.5317170613607207E-012
>>   cx           4   2.2344525794718353E-015
>>   cx           5   3.0624685689695889E-008
>>   cx           6   1.0046157902783967E-007
>>   cx           7   1.5320169154914984E-004
>>   cx           8   8.6930292776346176E-014
>>   cx           9   3.5944267559348721E-005
>>   cx          10   3.0072645866951157E-018
>>   cx          11   2.3592486321095017E-013
>>
>> Thanks,
>>
>> Danyang
>>
>>>> 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
>>>> timestep:    max.sia: 0.000E+00 tol.sia: 0.000E+00
>>>> timestep:    2731 time: 7.675E+00 years   delt: 1.000E-02 years iter:  1
>>>> timestep:    max.sia: 0.000E+00 tol.sia: 0.000E+00
>>>> timestep:    2732 time: 7.685E+00 years   delt: 1.000E-02 years iter:  1
>>>> timestep:    max.sia: 0.000E+00 tol.sia: 0.000E+00
>>>> timestep:    2733 time: 7.695E+00 years   delt: 1.000E-02 years iter:  1
>>>> timestep:    max.sia: 0.000E+00 tol.sia: 0.000E+00
>>>> timestep:    2734 time: 7.705E+00 years   delt: 1.000E-02 years iter:  1
>>>> timestep:    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
>>>> timestep:    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
>>>> timestep:    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
>>
>>

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