[Libmesh-devel] Raviart Thomas

[Rovi G. <gab...@us...>]

Hi,


I would like to implement the Raviart Thomas elements. In order to obtain a global basis function, if the global dofs of the actual element are such that:


n1 < n2 < n3 (2D) or n1 < n2 < n3 < n4 (3D)


then we have the mapping between:


 0 <——> n1

 1 <——> n2

 2 <——> n3

(3 <——> n4, 3D)



This kind of mapping can have a positive or negative determinant. So it can be that a clockwise element is mapped in the reference counterclockwise one.


Where is defined (header and source with the computation) the mapping between the reference and actual elements?

Is it defined as “counterclockwise <—>counterclockwise? If so, would be a drastic change to define another one like the one that I have now described?



To be consistent, the mapping must be  unique for all the shape functions (for example, the Lagrangian ones). Does this mean that I should change also these shape functions?


How do you suggest to proceed?


Thank you in advance


GR