BDSIM segfaulting on first event for AWAKE spectrometer example in 10.3
Running the AWAKE spectrometer.gmad example. BDSIM hangs at the first event. The problem does not occur at head of branch awake-develop-old-3.
Comments (11)
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- changed title to BDSIM hanging after firing one event for AWAKE spectrometer example
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I'm trying to make our dipole integrator more robust. In the case of the AWAKE spectrometer, you could safely use:
option, integratorSet="geant4";
to use all G4ClassicalRK4. The required accuracy is still relatively high and I rarely see anything fail with the RK4 integrator. I avoid this as a default as it's not good for tracking through longer lattices. This is a bit of a presumption though until I reproduce the warnings / hanging. It's a commonly observed failure mode though.
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@ldeacon : which Geant4 version was used? With Geant4.10.3 I get following segfault:
53: -------- WWWW ------- G4Exception-START -------- WWWW ------- 53: *** G4Exception : GeomNav0003 53: issued by : G4Navigator::GetLocalExitNormal() 53: Function called when *NOT* at a Boundary. 53: Exit Normal not calculated. 53: 53: *** This is just a warning message. *** 53: -------- WWWW -------- G4Exception-END --------- WWWW ------- 53: 53: 53: -------- EEEE ------- G4Exception-START -------- EEEE ------- 53: *** G4Exception : OpBoun01 53: issued by : G4OpBoundaryProcess::PostStepDoIt 53: G4OpBoundaryProcess/PostStepDoIt(): The Navigator reports that it returned an invalid normal 53: Invalid Surface Normal - Geometry must return valid surface normal 53: 53: *** Event Must Be Aborted *** 53: -------- EEEE -------- G4Exception-END --------- EEEE ------- 53:
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I am using Geant4.10.03, and I get the same result when running in batch mode.
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Okay. So one temporary solution could be to use 4.10.2, where I haven't seen this.
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In 10.3 I see the same segfault. This is definitely to do with optical boundaries. It happens in mySpectrometer_0_pv volume - or at least that's the last volume with --verbose_G4stepping=5.
The error only happens when "optical" physics is used.
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I would suggest we try to find a minimal example of this fault to understand it. We have a simple optical physics test and a simple screen example. Perhaps it would be good to make a multilayer screen example.
We have bdsim/examples/features/components/screen.gmad and bdsim/examples/processes/4_optical/optical.gmad. The last one though is 6MeV gamma rays, so it may be good to add a visible wavelength example, perhaps also with the multilayer screen.
For the AWAKE example it would be good to isolate which element this is happening in - perhaps it's an implementation problem or geometry (optical boundary) problem.
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- changed status to resolved
Resolved along with Issue
#186by fixing BDSTrajectory::MergeTrajectory implementation. - Log in to comment
@ldeacon : in which branch is this? I don't get that in develop for examples/AWAKE/awake.gmad or for examples/features/components/awakespectrometer.gmad