Problem 1923

Summary: G4WilsonRadius class using a wrong formula of root-mean-square radius
Product: Geant4 Reporter: Chen ShanQiang <chenshanqiang>
Component: processes/hadronic/models/utilAssignee: Alberto.Ribon
Status: RESOLVED FIXED    
Severity: minor CC: Gunter.Folger
Priority: P4    
Version: 10.2   
Hardware: All   
OS: All   

Description Chen ShanQiang 2016-12-03 14:29:18 CET
In G4WilsonRadius.cc file,GetWilsonRMSRadius(double A) fuction want to  calculates The root-mean-square radius.But, this fuction return the radius of a nucleus. According to Tripathi, Cucinnota and Wilson,Nucl Instrum Meth Phys Res B, 152, pp425-431, 1999, RMS RADIUS = 0.84*A**(1./3.)+0.55.
I am not sure that this is a bug,please check and send me an e-mail. thank you.
Comment 1 Alberto.Ribon 2016-12-14 14:51:18 CET
Although I am not the author of the code, by inspecting the code it seems fine to me. In fact, the method you refer to, G4WilsonRadius::GetWilsonRMSRadius, does correctly compute the RMS of the radius - not the radius.
Perhaps you got confused by the "bad" choice of the name of the local variable used inside the method: it is named "radius", instead of using a better-looking name as, for instance, "rmsRadius", but the name does not play any role!
The name of the method, instead, correctly refers to the RMS of the radius.
Comment 2 Chen ShanQiang 2016-12-14 17:11:34 CET
(In reply to Alberto.Ribon from comment #1)
> Although I am not the author of the code, by inspecting the code it seems
> fine to me. In fact, the method you refer to,
> G4WilsonRadius::GetWilsonRMSRadius, does correctly compute the RMS of the
> radius - not the radius.
> Perhaps you got confused by the "bad" choice of the name of the local
> variable used inside the method: it is named "radius", instead of using a
> better-looking name as, for instance, "rmsRadius", but the name does not
> play any role!
> The name of the method, instead, correctly refers to the RMS of the radius.
I'm not sure that RMS RADIUS = 0.84*A**(1./3.)+0.55 or 
RMS RADIUS = 1.29*0.84*A**(1./3.)+0.55?
Maybe I misunderstand the formula in the reference. and thanks for your reply.
Comment 3 Chen ShanQiang 2016-12-14 18:04:20 CET
(In reply to Alberto.Ribon from comment #1)
> Although I am not the author of the code, by inspecting the code it seems
> fine to me. In fact, the method you refer to,
> G4WilsonRadius::GetWilsonRMSRadius, does correctly compute the RMS of the
> radius - not the radius.
> Perhaps you got confused by the "bad" choice of the name of the local
> variable used inside the method: it is named "radius", instead of using a
> better-looking name as, for instance, "rmsRadius", but the name does not
> play any role!
> The name of the method, instead, correctly refers to the RMS of the radius.


I'm not sure that RMS RADIUS = 0.84*A**(1./3.)+0.55 or 
RMS RADIUS = 1.29*(0.84*A**(1./3.)+0.55)?
Maybe I misunderstand the formula in the reference. and thanks for your reply.
Comment 4 Chen ShanQiang 2016-12-14 18:04:42 CET
(In reply to Alberto.Ribon from comment #1)
> Although I am not the author of the code, by inspecting the code it seems
> fine to me. In fact, the method you refer to,
> G4WilsonRadius::GetWilsonRMSRadius, does correctly compute the RMS of the
> radius - not the radius.
> Perhaps you got confused by the "bad" choice of the name of the local
> variable used inside the method: it is named "radius", instead of using a
> better-looking name as, for instance, "rmsRadius", but the name does not
> play any role!
> The name of the method, instead, correctly refers to the RMS of the radius.


I'm not sure that RMS RADIUS = 0.84*A**(1./3.)+0.55 or 
RMS RADIUS = 1.29*(0.84*A**(1./3.)+0.55)?
Maybe I misunderstand the formula in the reference. and thanks for your reply.