Problem 1467

Summary:	checking overlaps in detector geometry issue
Product:	Geant4	Reporter:	Dan <fulea.dan>
Component:	geometry	Assignee:	Gabriele Cosmo <Gabriele.Cosmo>
Status:	RESOLVED INVALID
Severity:	normal
Priority:	P5
Version:	9.5
Hardware:	PC
OS:	Windows

Description Dan 2013-05-16 06:30:10 CEST

Running any application in interactive mode with default settings gives up a specific output, e.g. dose scoring. Running same application in batch mode using an input file, e.g. run1.mac, and the input file contains SAME settings as default settings gives up a DIFFERENT output. This happens when checking overlaps is true. If left out the checking overlap parameters in geometry, everything works fine!!!

In short:
When overlap flag is present, running detector construction twice (first time by default and second time when reading the input file, e.g. run1.mac) generates this nasty bug. When overlap flag is NOT present, running detector construction twice (first time by default and second time when reading the input file, e.g. run1.mac) generates NO bug. 

This bug can be tested running B1 example or any other geant4 example having overlap flag in detector construction class.

Comment 1 Gabriele Cosmo 2013-05-16 09:34:56 CEST

What observed is an expected behaviour, not a bug, as overlaps checking makes use of random numbers for the generation of points on the surface of volumes. This will clearly determine different sequences in the simulation either in interactive or batch modes.
Use of overlaps checking is meant to be done only for debug purposes for the geometry. It should not be used in production runs, also for reasons of efficiency.

Comment 2 Dan 2013-05-16 11:06:55 CEST

Thank you very much, it is just as I expect and therefore is not really a bug. I guessed that checking overlaps makes use of generating random number and therefore will produce different results for actual simulation.

One more thing, and maybe you can help me. As you probably know from my post, I am running 32 bit Windows 7 and Geant4.9.5. patch 02 using cmake 2.8.10 and visual studio 10. All are just fine. During last week I tried to install the new Geant4.9.6 with patch 01. It was installed fine, I changed environmental variables and I want to run any application (my own as well as some examples). None of applications work!!! I was forced to go back to Geant4.9.5. patch 02!!! The issue is opengl when trying to access visualization driver. Removing those lines of code generates other error regarding, I think, G4UImanager. I know there is a similar bug reported (openGl error)but no clear solution was given. Maybe the next patch will solve it, until then, I stick to my "old" Geant4 version.

Best regards,
Dan

Comment 3 Dan 2013-05-16 11:09:06 CEST

(In reply to comment #1)
> What observed is an expected behaviour, not a bug, as overlaps checking makes
> use of random numbers for the generation of points on the surface of volumes.
> This will clearly determine different sequences in the simulation either in
> interactive or batch modes.
> Use of overlaps checking is meant to be done only for debug purposes for the
> geometry. It should not be used in production runs, also for reasons of
> efficiency.

Thank you very much, it is just as I expect and therefore is not really a bug.
I guessed that checking overlaps makes use of generating random number and
therefore will produce different results for actual simulation.

One more thing, and maybe you can help me. As you probably know from my post, I
am running 32 bit Windows 7 and Geant4.9.5. patch 02 using cmake 2.8.10 and
visual studio 10. All are just fine. During last week I tried to install the
new Geant4.9.6 with patch 01. It was installed fine, I changed environmental
variables and I want to run any application (my own as well as some examples).
None of applications work!!! I was forced to go back to Geant4.9.5. patch 02!!!
The issue is opengl when trying to access visualization driver. Removing those
lines of code generates other error regarding, I think, G4UImanager. I know
there is a similar bug reported (openGl error)but no clear solution was given.
Maybe the next patch will solve it, until then, I stick to my "old" Geant4
version.

Best regards,
Dan

Comment 4 Gabriele Cosmo 2013-05-16 11:14:22 CEST

I am not aware of issues regarding running OpenGL visualization on Windows.
You should open a different problem report if you believe it is a real problem and not your specific configuration issue... or follow up on the problem report you refer to. Sorry...