Quasi-Optimal Elimination Trees for 2D Grids with Singularities

Figure 2

Exemplary basis functions spread over element supernodes: (a) basis function associated with vertex supernode 1 (black), vertex supernode 3 (dark gray), and vertex supernode 5 (light gray); (b) basis function associated with edge supernode 6 (black), edge supernode 8 (dark gray), and edge supernode 10 (light gray); (c) basis function associated with interior supernode 7 (black) and interior supernode 9 (dark gray).

(a)

(b)

(c)