[Getdp] [GetDP] Calculation of an Integral quantity

Matt Koch mattkoch at scitex.us
Sat May 5 16:49:28 CEST 2007


Hello Olivier,

thank you kindly for your reply. I took some time this morning to  
review your "Torus3D" example, trying to see if I could figure out  
what X vs. XS is. I noticed a couple of things that are not clear to me:

1) In FunctionSpace, you define function spaces on "D_tot" and  
"CoilSection", in Formulation, you define an Equation in these, but  
you also use that FunctionSpace to define two Quantities that work on  
"Coil", namely "a2" and "B2". How can a Quantity be defined on a  
region ("Coil") when it has no function space there?

2) I did note your use of X vs XS, but I still do not understand. To  
begin with, you seem to use J_s only, defined on X, and not  
J_s_source, defined on XS. So what is the point of working with XS?  
And then, how does one know when one is on X and when one is on XS? Or  
in other words, I sort of know that X are just the coordinates in the  
domain (they probably fall right out of the mesh), but what does XS  
represent? Does XS only become meaningful if I use certain functions?  
Can I define where I want my XS to be? If so, how?

3) The expression "Q(X,...) = \int_{XS,...} q(X,XS,...)" you mention  
below is pretty much what I am after, but I did not see where or how  
you implemented this in "Torus3D"?

Any thoughts here would be very much appreciated

Regards,

Matt Koch


----- Message from castany at quatramaran.ens.fr ---------
     Date: Thu, 3 May 2007 23:57:08 +0200
     From: Olivier Castany <castany at quatramaran.ens.fr>
Reply-To: Olivier Castany <castany at quatramaran.ens.fr>
  Subject: Re: [Getdp] [GetDP] Calculation of an Integral quantity
       To: getdp at geuz.org


>> since the discussion seems to be about XS[] or $XS, perhaps I can ask a
>> dumb question. I was trying to figure out what the difference is between
>> XS[] or $XS on one hand, and X[] or $X on the other hand, but I failed.
>> I was hoping XS could be defined on one surface, and X on an other, but
>> probably not. Can you tell me, in a nutshell, the meaning of XS vs. X?
>> And for that matter, of Normal[] vs. NormalSource[]?
>
> Hi,
>
> I created wiki pages. See :
> http://www.geuz.org/getdp/wiki/TorusCurrent3D
>
> - XS[] and $XS are probably the same but XS[] should be used in future
> versions. However, only $XS works with the current official version.
>
> - an integral quantity is calculated the following way :
> Q(X,...) = \int_{XS,...} q(X,XS,...)
>
> Regards,
>
> O.C.
>
> _______________________________________________
> getdp mailing list
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> http://www.geuz.org/mailman/listinfo/getdp
>


----- End message from castany at quatramaran.ens.fr -----