A Twisted Block Tangential Filtering Decomposition Preconditioner

Table 5

Results for Case 4: convective skyscraper problems. Top results are in 2D, bottom results are in 3D, 𝐭=(𝟏,𝟏,…,𝟏)^𝐓.

	𝑀𝐼𝐿𝑈		𝑀𝑇𝐹𝐹𝐷		𝑀𝑇𝐵𝑇𝐷		𝑀𝐼𝑇𝐹		𝑀𝐼𝑇𝐵
1/ℎ	iters	error	iters	error	iters	error	iters	error	iters	error
50	95	3.84𝑒−9	139	3.43𝑒−9	×	×	13	2.96𝑒−10	13	2.92−10
100	173	2.81𝑒−8	×	×	×	×	18	1.26𝑒−9	21	5.08𝑒−9
200	×	×	×	×	×	×	26	2.31𝑒−9	28	3.05𝑒−8
300	×	×	×	×	×	×	27	3.22𝑒−8	34	8.32𝑒−8
10	13	2.80𝑒−9	12	1.24𝑒−9	12	1.82𝑒−9	6	4.65𝑒−10	5	6.61𝑒−9
15	92	3.03𝑒−10	54	4.61𝑒−10	×	×	30	8.45𝑒−11	17	6.55𝑒−11
20	71	2.60𝑒−10	34	7.25𝑒−10	117	1.67𝑒−9	9	7.99𝑒−12	18	9.51𝑒−10
30	116	1.59𝑒−9	105	2.15𝑒−9	×	×	33	1.0𝑒−10	14	1.30𝑒−9