Git reference: Benchmark lshape.
This is a standard adaptivity benchmark whose exact solution is smooth but contains singular gradient in a re-entrant corner.
(2)u(x, y) = r^{2/3}\sin(2a/3 + \pi/3)
where r(x,y) = \sqrt{x^2 + y^2} and a(x,y) = \mbox{atan}(x/y).
Nonconstant Dirichlet, matching the exact solution.
Final mesh (h-FEM with linear elements):
Final mesh (h-FEM with quadratic elements):
Final mesh (hp-FEM):
DOF convergence graphs:
CPU time convergence graphs: