xifoam..floating point error..any interpretations?
Hello,
I am using a version of XiFoam and i get the following error: ----------------------------- [2] #0 Foam::error::printStack(Foam::Ostream&) in "/gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" [2] #1 Foam::sigFpe::sigHandler(int) in "/gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" [2] #2 __restore_rt at sigaction.c:0 [2] #3 Foam::sqrt(Foam::Field<double>&, Foam::UList<double> const&) in "/gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" [2] #4 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::sqrt<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<doub le, Foam::fvPatchField, Foam::volMesh> > const&) in "/gt/home/h250241/OpenFOAM/h250241-2.1.1/platforms/linux64GccDPOpt/bin/myXiFoam1" [2] #5 main in "/gt/home/h250241/OpenFOAM/h250241-2.1.1/platforms/linux64GccDPOpt/bin/myXiFoam1" [2] #6 __libc_start_main in "/lib64/tls/libc.so.6" [2] #7 _start in "/gt/home/h250241/OpenFOAM/h250241-2.1.1/platforms/linux64GccDPOpt/bin/myXiFoam1" [cubad10290:01470] *** Process received signal *** [cubad10290:01470] Signal: Floating point exception (8) [cubad10290:01470] Signal code: (-6) -------------------------------------------- Any idea what it means? Could anybody tell where the error is originating. The solver runs fine for 2500 time steps and then diverges showing this error!!! Kind regards, A V |
Greetings Achinta,
See the line in bold below? Quote:
If you want to isolate better the problem, you'll need to do a debug build. Here's an old thread on this subject: Debug version of OpenFOAM-1.6 Best regards, Bruno |
Thanks for the reply Bruno. Some some equations are giving wrong results i guess. I will check. Btw, when i use 'foamToVTK' command to covert OpenFoam files to VTK format, i get the following error
----- Internal : "/gt/home/h250241/OpenFOAM/h250241-2.1.1/run/tub_sst_piso1/VTK/t ub_sst_piso1_500.vtk" #0 Foam::error::printStack(Foam::Ostream&) in "/gt/home/h250241/OpenFOAM/OpenFO AM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #1 Foam::sigFpe::sigHandler(int) in "/gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/p latforms/linux64GccDPOpt/lib/libOpenFOAM.so" #2 __restore_rt at sigaction.c:0 #3 Foam::writeFuns::insert(double, Foam::DynamicList<float, 0u, 2u, 1u>&) in "/ gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/foamToVTK" #4 void Foam::writeFuns::insert<double>(Foam::List<double> const&, Foam::Dynami cList<float, 0u, 2u, 1u>&) in "/gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platform s/linux64GccDPOpt/bin/foamToVTK" #5 void Foam::writeFuns::write<double>(std::ostream&, bool, Foam::GeometricFiel d<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::vtkMesh const&) in "/ gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/foamToVTK" #6 void Foam::internalWriter::write<double, Foam::fvPatchField, Foam::volMesh>( Foam::PtrList<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > const&) in "/gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/b in/foamToVTK" #7 main in "/gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/ bin/foamToVTK" #8 __libc_start_main in "/lib64/tls/libc.so.6" #9 _start in "/gt/home/h250241/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOp t/bin/foamToVTK" Floating point exception ------------------- Well, it seems some operations are bad. But, i am just converting files. I am not doing any calculations. Do you know why this error is happening? Kind regards, Achinta |
Hi Achinta,
I think that error implies that the saved fields are already contaminated with either NaN or inf values. If the option in "controlDict" is to use "ascii", you can open the field files for the "500" folder and check if there are values that are not numbers. If you find those values, then it's only natural that you can't export them to VTK. Best regards, Bruno |
Hi Bruno,
I checked all the files of that folder and i didn't find any NaN or inf. I have paraFoam installed on my laptop and i can open those files using paraFoam. But, i couldn't install paraFoam on my Desktop but I have paraview. So, to view the results on my desktop i have to use foamToVTK command. But it gives this error when i try to convert. In fact, foamToVTK converted the files of other cases, but it's causing problem with this specific case only. Do i have to change any setting in system folder or something? Thanks again, Kind regards, Achinta |
Hi Achinta,
OK, I would suggest the following ideas:
Good luck! Bruno |
Hi Bruno,
Sorry for the late reply. Other issues with OpenFoam had kept me busy :( btw, i tried your suggestions and here are the results: Method 1) It was giving same error with other folders too!! Method 2) It works!! when i post-process results, all the parameters were within reasonable limits. No idea why it was giving sigFpe error i have a question related to: unset FOAM_SIGFPE unset FOAM_SETNAN Does it allow OpenFoam to run even if there are NaNs or Infs? The solver gives similar sigFpe error related to mutWallFunction with XiFoam and i would like the solver to run even if such error happens ( i guess few bad cells in my 'industrial' mesh are causing such errors and may not effect the overall solution. So i want to ignore such errors) Thank you very much Kind regards, Achinta |
Hi Achinta,
When FOAM_SIGFPE is turned on, it will not allow erroneous values to go around. But there are some situations where you can turn this off, at least until you can figure out the source of the problem. It could even be an initialization that later on is dumped because new proper values are calculated. This can be a fallacy, because you might be allowing crazy values to go into your simulation domain and wreck havoc sooner or later. The right way to do this would be to diagnose where exactly the problem is and fix it properly. As for FOAM_SETNAN, when turned on (not the default), I think it has to do with a method for initializing all fields with NAN, to help diagnose situations where non-initialized fields are being used and which can lead to crazy or unreproducible results. Best regards, Bruno |
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