[Getdp] [GetDP] Calculation of an Integral quantity

[Matt Koch]

Hi there,

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[]?

Thanks,

Matt Koch


Christophe Geuzaine wrote:

>Olivier Castany wrote:
>  
>
>>Hello,
>>
>>    
>>
>>>Yes. Both XS[] and $XS can normally be used, but I recommend using XS[], 
>>>as $XS has not been tested and is not guaranteed to be valid in all 
>>>expressions.
>>>      
>>>
>>If I change $XS into XS[], I always get the error :
>>
>>GetDP   : Error ('torus.pro' line 142): Unknown Function: XS
>>    
>>
>
>Weird... Maybe XS[] was not defined in the last official release. Can 
>you try with the "nightly-source" version? (cf. http://geuz.org/getdp/src/)
>
>
>
>  
>
>>>The "sign reversal" in D_inf comes from the fact that the elements in 
>>>your mesh are reversed in that region... Be careful to create your mesh 
>>>with normals pointing in the correct direction.
>>>      
>>>
>>Well... there is no reason why the result should depend on the 
>>orientation of that region...
>>
>>but your remark lead me to the solution !!!
>>
>>FUCK AN EGG !!! I found my mistake !
>>
>>I was using Normal[] instead of NormalSource[] !!!
>>
>>Now it works (with $XS...)
>>
>>Thanks,
>>
>>O.C.
>>
>>
>>    
>>
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