This class computes discrete gradient operators (matrices) that map derivatives of finite element functions into other finite element spaces. An example of where discrete gradient operators are required is the creation of algebraic multigrid solvers for H(curl) and H(div) problems. NOTE: This class is highly experimental and likely to change. It will eventually be expanded to provide the discrete curl and divergence.
Build the discrete gradient operator A that takes a w in H^1 (P1, nodal Lagrange) to v in H(curl) (lowest order Nedelec), i.e. v = Aw. V0 is the H(curl) space, and V1 is the P1 Lagrange space.
The membership flag