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

Table 3

Number of CG/MPCG iterations (using stopping criterion (4.6) for 𝜀=10⁻⁶) for various nested uniform mesh levels.

Level	Mesh size ℎ	Problem size	CG iterations	MPCG iterations
0	1	5	2	2
1	2^−1	16	5	5
2	2^−2	56	15	8
3	2^−3	208	45	10
4	2^−4	800	108	11
5	2^−5	3136	219	11
6	2^−6	12416	349	11
7	2^−7	49408	877	11
8	2^−8	197120	1773	11
9	2^−9	787456	3506	11