[Gate-users] Some news about the strange behaviour
Chen, Yu
Yu.Chen at umassmed.edu
Fri Dec 21 16:57:56 CET 2007
Thank Simon for thorough investigation.
However, it seems that the thing does not become clearer but even more confusing. See below.
Simon Stute wrote:
> Hi all,
>
> I dug more to find the reason of the strange behaviour in energy spectra
> and found those results :
>
> - I first installed Gate3.0.0, 3.1.0, 3.1.1 and 3.1.2 on both 32 and 64
> bits architectures,and both cluster and single PC.
> - I ran PET and SPECT benchmark on all configurations and compared both
> energy spectra and results from benchmark.C with root : everything was
> identical between all different config.
1, It suggests that either no significant difference between GATE versions or
benchmark configuration is not able to reveal any difference.
> - Then I ran the single_layer.mac simulation on all config and obtained
> the same difference in energy spectra as Irene and Jasmine reported.
2, different behaviors come from different comfigurations.
I found that major differences between benchmarkPET.mac and single_layer.mac are:
1) physics list,
benchmarkPET:
# EM P R O C E S S
/gate/physics/gamma/selectRayleigh lowenergy
/gate/physics/gamma/selectPhotoelectric standard
/gate/physics/gamma/selectCompton standard
# I N A C T I V E S E C O N D A R Y E L E C T R O N S
/gate/physics/setElectronCut 30. cm
# I N A C T I V E X - R A Y S
/gate/physics/setXRayCut 1. GeV
/gate/physics/setDeltaRayCut 1. GeV
/gate/physics/verbose 2
single_layer:
/gate/physics/gamma/selectPhotoelectric standard
/gate/physics/gamma/selectCompton standard
/gate/physics/gamma/selectRayleigh inactive
# High cuts for fast simulation
/gate/physics/setElectronCut 3. m
/gate/physics/setXRayCut 1. GeV
/gate/physics/setDeltaRayCut 1. GeV
/gate/physics/verbose 0
2), setDepth 1 for benchmarkPET and 5 for single_layer.
> Then I found that the change in energy spectra occurs between Gate3.0.0
> and 3.1.0. Results from 3.1.0, 3.1.1 and 3.1.2 were the same. (see
> attached images)
> - I realised then that between Gate3.0.0 and 3.1.0, the associated
> Geant4 versions are 8.0.p01 and 8.1.p02. And between these two different
> Geant4 versions one of the main changes was the upgrade of the most
> important data package G4EMLOW, that move from 3.0 to 4.0, and that
> includes major changes.
3, G4EMLOW is a data lib used by EM Low Energy model in Geant4.
As we can see, only benchmarkPET used low energy Rayleigh and single_layer used
all standard model physics processes for PE and Compton. Any change in G4EMLOW
should only affect benchmarkPET not single_layer.
Any major change of standard EM model between Geant4 8.0.p01 and 8.1.p02?
> - I decided then to run the single_layer.mac simulation with Gate3.1.0,
> Geant4.8.1.p02 and to change the G4EMLOW4.0 package with G4EMLOW3.0
> package from the older version. Then the energy spectra obtained was
> more similar than this obtained with Gate3.0.0, but still different (see
> energy_3.1.0.EMLOW3.0.jpg image). So I think this little difference is
> due to other main changes between Geant4.8.0.p01 and Geant4.8.1.p02, it
> is statistical I think.
4, This is really confusing!
> - The change in behaviour do not come from any digitizer module (adder,
> readout, any blurring ...), they are still the same since Gate3.0.0 and
> even before, I compared all files and algorithms.
5, This may be true. But as parameter setDepth is different, the function of multiple pulses
per rsector in readout module may not be tested thoroughly in different configurations.
> - For me it is not possible too to have such differences only due to gcc
> version or stdlib version. But here I ask myself a question : MJ, you
> said you get results with 3.1.2 similar to 3.0.0 but what G4 data
> packages do you use ?? Then if you use the good packages version, I do
> not understand anything anymore ... Let me know your thoughts about that.
6, That is still the first thing we should know:
Is the strange behavior from physics basis (Geant4 etc) or from coding?
Since MJ is the only one reported no difference, we do need a definite answer from you!
> - I will now try to reproduce the problem in intersector coincidences
> with the Gate coincidence sorter to see where this problem come from and
> to see if it is relative to the energy spectra problem too.
>
7, Good.
> But now, it is time to go on holidays :-)
> Dig, dig, dig and dig more as say MJ !
8. More homework for Irene and Jasmine:
Always set bluring to 0.01:
1) set the exact physics from benchmarkPET in your single_layer (even verbose level); run to see ?
2) setDepth 1; same as benchmarkPET now?
3) other assignments yesterday.
Have a wonderful holidays!
> Cheers,
> Simon
>
> PS : sorry but I send the images in different mails due the size limitation.
>
> ------------------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Gate-users mailing list
> Gate-users at lists.healthgrid.org
> http://lists.healthgrid.org/mailman/listinfo/gate-users
Yu Chen, Ph.D.
University of Massachusetts Medical School
Division of Nuclear Medicine
55 Lake Avenue North
Worcester, MA 01655-0243
Phone: (508) 856-6123
Fax: (508) 856-4572
-----Original Message-----
From: gate-users-bounces at lists.healthgrid.org on behalf of Simon Stute
Sent: Fri 12/21/2007 6:15 AM
To: gate-users
Subject: [Gate-users] Some news about the strange behaviour
Hi all,
I dug more to find the reason of the strange behaviour in energy spectra and
found those results :
- I first installed Gate3.0.0, 3.1.0, 3.1.1 and 3.1.2 on both 32 and 64 bits
architectures,and both cluster and single PC.
- I ran PET and SPECT benchmark on all configurations and compared both
energy spectra and results from benchmark.C with root : everything was
identical between all different config.
- Then I ran the single_layer.mac simulation on all config and obtained the
same difference in energy spectra as Irene and Jasmine reported. Then I
found that the change in energy spectra occurs between Gate3.0.0 and 3.1.0.
Results from 3.1.0, 3.1.1 and 3.1.2 were the same. (see attached images)
- I realised then that between Gate3.0.0 and 3.1.0, the associated Geant4
versions are 8.0.p01 and 8.1.p02. And between these two different Geant4
versions one of the main changes was the upgrade of the most important data
package G4EMLOW, that move from 3.0 to 4.0, and that includes major changes.
- I decided then to run the single_layer.mac simulation with Gate3.1.0,
Geant4.8.1.p02 and to change the G4EMLOW4.0 package with G4EMLOW3.0 package
from the older version. Then the energy spectra obtained was more similar
than this obtained with Gate3.0.0, but still different (see
energy_3.1.0.EMLOW3.0.jpg image). So I think this little difference is due
to other main changes between Geant4.8.0.p01 and Geant4.8.1.p02, it is
statistical I think.
- The change in behaviour do not come from any digitizer module (adder,
readout, any blurring ...), they are still the same since Gate3.0.0 and even
before, I compared all files and algorithms.
- For me it is not possible too to have such differences only due to gcc
version or stdlib version. But here I ask myself a question : MJ, you said
you get results with 3.1.2 similar to 3.0.0 but what G4 data packages do you
use ?? Then if you use the good packages version, I do not understand
anything anymore ... Let me know your thoughts about that.
- I will now try to reproduce the problem in intersector coincidences with
the Gate coincidence sorter to see where this problem come from and to see
if it is relative to the energy spectra problem too.
But now, it is time to go on holidays :-)
Dig, dig, dig and dig more as say MJ !
Cheers,
Simon
PS : sorry but I send the images in different mails due the size limitation.
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