[Gate-users] problem about the new version of GATE (V3.0) (bug?)

[Sebastien JAN]

Thanks for your remark and contribution

Cheers
Sebastien JAN

yuxuan.zhang at di.mdacc.tmc.edu wrote:
> 
> Sorry I forgot to attach the test bench result in the former email,
> here it is.
> 
> 
> 
> 
> 
> Hi,
> 
> Recently I installed the new version of the GATE v3.0 into my computer
> with Geant4.8.0.p01, CLHEP2.0.2.2, and the compiler is gcc4.0.1 and
> the Linux version is Scientific Linux CERN.
> 
> After I installed the GATE, I ran the test bench of the PET and the result
> is shown here as the attachment. From the result, you will see there are
> only 7 sectors in the detector ring, which should be 8.
> Then I checked with my own camera geometry and every time the sector 
> numbers
> was short of 1 as what I have defined.
> 
> I checked the source code of GATE and find such code in 
> GateAngularRepeater.cc
> .
> .
> .
> void GateAngularRepeater::PushMyPlacements(const G4RotationMatrix& 
> currentRotationMatrix,
>                                                          const 
> G4ThreeVector& currentPosition,
>                                                          G4double )
> {
>   G4double dphi ;
>   if ( m_angularSpan == 360. *deg)
>   dphi = GetAngularPitch_1();
>   if ( m_angularSpan != 360. *deg)
>   dphi = GetAngularPitch_2();
> .
> .
> .
> 
> 
> I think that the comparision of two float type like this ( m_angularSpan 
> == 360. *deg)
> is dangeous, sometimes it works fine but sometimes it may give wrong 
> result based on what
> kind of compiler, system or cpu are used.
> 
> So I changed the code as this:
> 
>   if ( m_angularSpan < 360.0005 *deg &&  m_angularSpan > 359.9995 *deg)
>   dphi = GetAngularPitch_1();
>   else
>   dphi = GetAngularPitch_2();
> 
> After recompile the Gate, now the result seems ok.
> 
> 
> I also checked the old versions of GATE, they were all coded in the same 
> way and I didn't have
> this problem before. So I think it mostly caused by the different 
> compiler (gcc4).
> This just a reminder to you if you have the same proble in your computer.
> 
> 
> Yuxuan
> 
> ------------------------------------------------------------------------
> 
> 
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