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items: Geant 3 crashes on hadron events
items: Re: Geant 3 crashes on hadron events

Geant 3 crashes on hadron events
type: item
description: Hello, G3-G4-VMC experts! I have the following problem running simulation. I throw particles on my detector and collect edep. When I use electromagnetic particles i get no problems at all. But if i use hadrons (neutrons, pions) Geant3 crashes at some event number... In Geant4 I don't have such a problem (the results are funny in g4, but at least it works ). Here is the output of my sim script: ----------------------------------------------------------- PSaid instance created... access via gSaid->f() - RTDB container factory CbmBaseContFact - RTDB container factory CbmFieldContFact - RTDB container factory CbmPassiveContFact SetStoreTraj1 -I CbmAsciiGenerator: Opening input file output2.evt ============== CbmRunSim: Initialising simulation run ============== Info in <TGeoManager::TGeoManager>: Geometry CBMGeom, CBM geometry created Loading Geant3 libraries ... Loading Geant3 libraries ... finished CbmMCApplication::InitMC MZSTOR. ZEBRA table base TAB(0) in /MZCC/ at adr 42186663 283B7A7 HEX MZSTOR. Initialize Store 0 in /GCBANK/ with Store/Table at absolute adrs 42209213 42186663 HEX 2840FBD 283B7A7 HEX 5662 0 relative adrs 22114 0 with 1 Str. in 2 Links in 5300 Low words in 4999970 words. This store has a fence of 16 words. MZLOGL. Set Log Level 0 for store 0 1***** GEANT Version 3.21/11 Released on 100298 0***** Correction Cradle Version 0.1100 MZDIV. Initialize Division Constant in Store 0 NW/NWMAX= 20004000000, MODE/KIND= 1 2 Division 20 initialized. MZLINK. Initialize Link Area /GCLINK/ for Store 0 NL/NS= 20 20 MZLINK. Initialize Link Area /GCSLNK/ for Store 0 NL/NS= 100 100 -I- G3Config: Geant3 with TGeo has been created. Info in <TGeoManager::SetTopVolume>: Top volume is cave. Master volume is cave Mixture Air Aeff=15.1708 Zeff=7.52797 rho=0.00125 radlen=28819.7 index=1 Element #0 : O Z= 8.00 A= 16.00 w= 0.229 Element #1 : N Z= 7.00 A= 14.01 w= 0.744 Element #2 : AR Z= 18.00 A= 39.95 w= 0.027 Mixture Polysterene Aeff=11.1591 Zeff=5.61287 rho=1.032 radlen=42.04…
creator: Dmitry Morozov
date: 2007-05-30T07:35:09-00:00

Re: Geant 3 crashes on hadron events
type: item
description: Hi I have actually the same problem when I try to run my simulation (strange baryons) in geant3. any ideas? Maybe it is related with the set up process in the g3config.C. I don't know. cheers Alicia
creator: asanchez
date: 2007-05-30T08:20:02-00:00

Re: Geant 3 crashes on hadron events
type: item
description: Hi Dmitry May I ask you which generator are you using? I get the same error by using Ascii and Particle generator. cheers Alicia.
creator: asanchez
date: 2007-05-30T08:27:15-00:00

Re: Geant 3 crashes on hadron events
type: item
description: Hi Dimitry, I suggest you to add printouts in the ProcessHit function of your subdetector, to understand in which point the simulation crashes. For debug purposes I found very useful also the lines usually commented in base/CbmMCApplication.cxx line 386 Debug for Geant tracking (inside CbmMCApplication::Stepping function) if you uncomment the sprintf you get the volumes tracked for each geant step and you might understand in which material happens the crash. In my experience with the straw tubes I simulated also pions and protons but I did not see such a crash. I do not know if this information helps you... ciao, Pablo
creator: Pablo Genova
date: 2007-05-30T10:55:37-00:00

Re: Geant 3 crashes on hadron events
type: item
description: Alicia,it does not depend on generator. Only on Geant version. Pablo, thanks for the info! I'll try to check this. Dmitry.
creator: Dmitry Morozov
date: 2007-05-31T06:41:47-00:00

Re: Geant 3 crashes on hadron events
type: item
description: Hi everybody You can look at the actual line where it happens. FACFLU = DME*(Z*DENS/A) Since it is a floting point exception i would assume that there is a devision by zero. This mean that you have defined some strange material with A=0. Looking in the media file i didn't find anything except the vacuum which has A=1.e-16. Maybe there is a problem with the accuracy. But here the information about the material would help. Ciao Florian
creator: Florian Uhlig
date: 2007-05-31T16:17:33-00:00

Re: Geant 3 crashes on hadron events
type: item
description: I found the bug. Thank you everybody for the useful comments. Since in my subdetector i use TGeoManager to create geometry, volumes and media - I did not use "media.geo" file in sim macro: fRun->SetMaterials("media.geo"). But i forgot that CAVE uses this file! So my cave did not have any media.... G4 was eating it without problem, but G3 is more scrupulous. I think this is because you always have sig fault deviding by zero in Fortran (G3) but not in C++ (G4). Thank you again! Dmitry.
creator: Dmitry Morozov
date: 2007-06-05T13:34:29-00:00