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Forum: Geometry
Re: None How is Base Material Optimized? (Youming Yang)
Re: None RE: How is Base Material Optimized? (Vladimir Ivanchenko)
Date: 21 Jun, 2012
From: Youming Yang <Youming Yang>

Hello Vladimir,

Thank you for such a fast reply.
I apologize for how confusing my previous post was, I copy-pasted my code 
and it's a bit unreadable.

-I am declaring a new base material in tissues[i].  Therefore I add 
elements.
-For tissues[i+1], I am using tissues[i] as the base material, but with a 
different density.

I have about 18 different "base materials" declared in such a way (like 
tissues[i], and 4000+ additional materials defined via 
BuildMaterialWithNewDensity.

I would like to confirm two things:
1.  Does buildmaterialwithnewdensity work for custom (non NIST) materials 
such as where I add individual elements
2a.  For a parameterized geometry where the Material scan needs to create 
all the tables, how should I give it materials?  Should I give it my 18 base 
materials, or should I give it my 4000+?
2b.  Additionally, will Geant4 automatically know that tissues[i] and 
tissues[i+1]  are the same material with different density scaling?  Or will 
I need to enforce that somehow under my parameterized ComputeMaterial 
section?

Thank you again,
Ming

-----Original Message----- 
From: Vladimir Ivantchenko
Sent: Thursday, June 21, 2012 2:58 AM
To: Youming Yang ; geometry-g4hn@slac.stanford.edu
Subject: RE: How is Base Material Optimized?

Hello,

Sorry, you should not add elements to material, if it has been defined via 
base material constructor.

We will verify why there is no exception in that case but obviously logic is 
broken: one has to choose - build material from scratch or from base 
material but not both.

VI

-----Original Message-----
From: Youming Yang [mailto:ymyang@wisc.edu]
Sent: Thursday, June 21, 2012 9:54 AM
To: geometry-g4hn@slac.stanford.edu
Subject: How is Base Material Optimized?


*** Discussion title: Geometry

Hello, I am wondering how to properly leverage the benefits of the base 
material functionality.

I have a voxelized geometry which creates 4072 materials of varying density 
off of 18 base materials. I have it programmed like such:

tissues[i]= new G4Material(materialBaseName.str(),density[i]*g/cm3,9);
tissues[i]->AddElement(eH,0.036); tissues[i]->AddElement(eC,0.165); 
tissues[i]->AddElement(eN,0.042); tissues[i]->AddElement(eO,0.432); 
tissues[i]->AddElement(eNa,0.001); tissues[i]->AddElement(eMg,0.002);
tissues[i]->AddElement(eP,0.100); tissues[i]->AddElement(eS,0.003); 
tissues[i]->AddElement(eCa,0.219);

tissues[i+1]=
man->BuildMaterialWithNewDensity(materialName.str(),materialBaseName.str
man->(),density[i+1]*g/cm3);

However, my code is still very slow after run/beamon. Currently, the 
GetMaterial function runs through all 4072 materials during the materials 
scan. Does the base material only allow ease of initialization of the 
materials list, or is there an added benefit such as being able to claim I 
only have 18 materials total during the material scanner?

Thank you, Ming

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1 None: Re: How is Base Material Optimized?   (John Apostolakis - 21 Jun, 2012)
2 Idea: Re: How is Base Material Optimized?   (Vladimir Ivanchenko - 21 Jun, 2012)
3 None: Re: How is Base Material Optimized?   (Ming - 21 Jun, 2012)
1 None: Re: How is Base Material Optimized?   (John Apostolakis - 21 Jun, 2012)
1 None: Re: How is Base Material Optimized?   (Ming - 21 Jun, 2012)
2 None: Re: How is Base Material Optimized?   (Youming Yang - 22 Jun, 2012)
... 1 Message(s)
3 None: Re: How is Base Material Optimized?   (Ming - 22 Jun, 2012)
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