Minimization of Functional Majorant in a Posteriori Error Analysis Based on 𝐻(div) Multigrid-Preconditioned CG Method

Table 2

Comparison of the square of exact error ‖∇(𝑢−𝑣)‖²_Ω and majorant values ℳ and on various uniform meshes levels.

Level	DOF 𝑣	‖∇(𝑢−𝑣)‖^2Ω	DOF 𝑦	Majorant ℳ	𝐼eff
1	9	8.873457e-03	16	2.135435e-02	1.55
2	25	3.240138e-03	56	9.050160e-03	1.67
3	81	8.950033e-04	208	2.635564e-03	1.72
4	289	2.295153e-04	800	6.858397e-04	1.73
5	1089	5.774695e-05	3136	1.732119e-04	1.73
6	4225	1.445987e-05	12416	4.341359e-05	1.73
7	16641	3.616415e-06	49408	1.086033e-05	1.73
8	66049	9.041944e-07	197120	2.715516e-06	1.73