Degrees of Freedom

This module groups classes and namespace that have to do with handling degrees of freedom. The central class of this group is the DoFHandler class: it is built on top of a triangulation and a finite element class and allocated degrees of freedom on each cell of the triangulation as required for the finite element space described by the finite element object.

DoFHandlers extend Triangulation objects (and the other classes in the Grid classes module) in that they, too, offer iterators that run over all cells, faces, or other geometric objects that make up a triangulation. These iterators are derived from the triangulation iterators and therefore offer the same functionality, but they also offer additional functions. For example, they allow to query the indices of the degrees of freedom associated with the present cell.

In addition to the DoFHandler class, this module holds a number of auxiliary classes not commonly used in application programs, as well as three classes that are not directly associated with the data structures of the DoFHandler class. The first of these is the ConstraintMatrix class that stores and treats the constraints associated with hanging nodes. Secondly, the DoFRenumbering namespace offers functions that can reorder degrees of freedom; among its functions are ones that sort degrees of freedom in downstream direction, for example, and ones that sort degrees of freedom in such a way that the bandwidth of associated matrices is minimized. Finally, the DoFTools class offers a variety of algorithms around handling degrees of freedom.


deal.II documentation generated on Tue Mar 15 2011 18:45:22 by doxygen 1.7.3