I told you this yesterday. It is probably stopping here on a harmless underflow. You need to edit the PETSc code to not worry about underflow.
Edit the file /home/dsu/Soft/PETSc/petsc-3.5.2/src/sys/error/fp.c and locate #elif defined PETSC_HAVE_XMMINTRIN_H _MM_SET_EXCEPTION_MASK(_MM_MASK_INEXACT); #else change it to #elif defined PETSC_HAVE_XMMINTRIN_H _MM_SET_EXCEPTION_MASK(_MM_MASK_INEXACT | _MM_MASK_UNDERFLOW); #else Then run make gnumake in the PETSc directory to compile the new version. Now link and run the program again with -fp_trap and see where it gets stuck this time. Did you do this? Barry > On Apr 25, 2015, at 1:05 AM, Danyang Su <[email protected]> wrote: > > Hi Barry and Satish, > > How can I get rid of unknown floating point error when a very small value is > multiplied. > > e.g., > cinfrt_dg(i1) and diff(ic,idim) are 1.0250235986806329E-008 > 8.6178408169776945E-317 respectively, > > cinfrt = cinfrt_dg(i1) * diff(ic,idim) > > I get the following error when run with "-fp_trap -start_in_debugger". > > Backtrace for this error: > *** unknown floating point error occurred *** > [2]PETSC ERROR: The specific exception can be determined by running in a > debugger. When the > [2]PETSC ERROR: debugger traps the signal, the exception can be found with > fetestexcept(0x3d) > [2]PETSC ERROR: cinfrt_dg(i1),diff(ic,idim) 1.0250235986806329E-008 > 8.6178408169776945E-317 > where the result is a bitwise OR of the following flags: > [2]PETSC ERROR: FE_INVALID=0x1 FE_DIVBYZERO=0x4 FE_OVERFLOW=0x8 > FE_UNDERFLOW=0x10 FE_INEXACT=0x20 > [2]PETSC ERROR: Try option -start_in_debugger > [2]PETSC ERROR: likely location of problem given in stack below > > Thanks, > > Danyang > > On 15-04-24 01:54 PM, Danyang Su wrote: >> 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 <[email protected]> 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@nwmop] Sending Ctrl-C to processes as requested >>>>>> [mpiexec@nwmop] Press Ctrl-C again to force abort
