ffc team mailing list archive

["Garth N. Wells" <g.n.wells@xxxxxxxxxx>]

Dag Lindbo wrote:
> Hi all,
> 
> I'm using an appropriate mixture of continous and discontinuous elements
> in my FFC/DOLFIN work (with a great deal of sucess). Now, I'd like to know
> how the degrees of freedom are arranged for discontinuous elements and how
> that goes into the DOLFIN Vectors.
> 
> For a 'Discontinuous Lagrange' order 0 triangular element, is it correct
> that the degree(s) of freedom is just the value on the edge? I.e. a Vector
> in DOLFIN for a Function on this element would contain [value at edge 0,
> value at edge 1, ... ]?
> 

No, it's for elements, not edges. The position i in the vector
corresponds to the degree of freedom belong to element i.

> For a 'Discontinuous Lagrange' order 1 triangular element, I can't really
> guess what the logical ordering is. Please help.
> 

The ordering is per element. Hence, for a discontinuous linear function,
positions 0, 1 & 2 in the vector correspond to element 0, and positions
3, 4 & 5 correspond to the degrees of freedom of element 2, etc.

Garth

> Thanks a lot!
> Dag Lindbo
> 
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