[deal.ii] problems with build_patches() and transform_covariant()

[Baerbel Janssen]

Dear all,

I am in some trouble. My questions arise because I try to implement the 
Adini and Bogner-Fox-Schmit finite elements for deal.II. These are 2D 
elements that use partial derivatives as degrees of freedom. The 
associated polynomials have an oder up to three.

I would like to be able to use these elements on parallelograms. Therefore 
I wrote a mapping similar to the MappingQ1. This transforms quadrature 
points as well as the four corner points.

Some problems occur due to the transform_covariant() method. Can someone 
briefly introduce me to the changes that have been made in MappingQ1? For 
example: Why has the DeclException0 (ExcAccessToUninitializedField) disappeared? And 
why do I have to use the update_covariant_transformation as a user flag?

Next problem is the graphical output. I use the method build_patches() in 
DataOut. Is there a problem because I use poynomials of order three and 
three subdivisions in build_patches? How is the interpolation made on the 
"subcells"?

Thak you very much for any little hint :-)

Cheers,
Bärbel Janssen_______________________________________________