After update to Geant4 patch1 (31 January 2002) we are getting exception: G4VProcess::SubtractNumberOfInteractionLengthLeft() negative currentInteractionLength After tracing where it comes from I reproduced this within example N03 by changing primary generator particle to pi0. The problem becomes when in G4Decay the pi0 products (gammas) are boosted (G4DecayProducts::Boost) - after boosting one of products gets "nan" energy. I put in: /afs/cern.ch/user/i/ivana/public/g4exception the modifications I did in exampleN03 to reproduce this problem plus the output with this exception.
This G4exception occurs only by using gcc version 2.96 on Redhat 7.X. This version of gcc is a flawed version which has -never- been officially released by GNU. I recommend you to use gcc version 2.95 or gcc-egcs 2.91 which are officially supported by Geant4 group.
I can confirm that the crash occurs only with compiler gcc-2.96 (in RH 7.0/1/2). I also verified on the latest gcc-3.0.4 on a RH-7.2 system; here the test runs fine...
Ivana Hrivnakova writes: We have experienced again this problem with Geant4.4.1 + patch01 with gcc 3.1 (on RH 7.1) and gcc 3.2 (I don't know the system exactly) when using granular shared libraries with optimization; the problem disappears when source/particles/management/G4DynamicParticle.cxx source/particles/management/G4DynamicProducts.cxx are compiled without optimization.
I verified that on gcc-3.2 (RH-7.2) the problem can be reproduced (using also static libraries). Change the gun particle to 'pi0' in exampleN03.in (examples/novice/N03) and shoot a reasonable statistics (5 events) at 300 MeV ...
Christophe Delaere (delaere@fynu.ucl.ac.be) reports: > > I've the following problem for some events (~1/100) in my simulation. > ***************************************************************************** > * G4Track Information: Particle = gamma, Track ID = 3, Parent ID = 1 > ***************************************************************************** > > Step# X(mm) Y(mm) Z(mm) KinE(MeV) dE(MeV) StepLeng TrackLeng > NextVolume ProcName > 0 416 -13.8 -12 nan 0 0 0 > target initStep > 1 375 -47.2 68.3 nan 0 96 96 > expHall Transportation > G4VProcess::SubtractNumberOfInteractionLengthLeft() negative > currentInteractionLength > > *** G4Exception: Aborting execution *** > Aborted > > My configuration is quite different: > > G4 v 4.5.0 > RH 8.0 - gcc 3.2 > > I'm shooting ~20MeV neutrons on a H2O target with some B10 in it. I'm using > the LHEP_PRECO_HP physics list. > > Hope this information can help you, > Christophe.
The problem was simply a matter of a missing protection of 'sqrt' in G4DynamicParticle::Set4Momentum(). The tag partman-V05-00-06 includes the fix.
