%% Data Sturcture for Degree of Freedom (DOF) 
%
% For various elements, dofs could be associated to vertices, edges, or
% faces with apporipate orientation. In this doc, we collect data
% structures for commonly used elements.
%
% * <dofedgedoc.html Dof on edges: 2-D>
% * <dof3edgedoc.html Dof on edges: 3-D>
% * <dofP2doc.html Dof of P2 elements>