A Twisted Block Tangential Filtering Decomposition Preconditioner

Table 3

Results for Case 3: skyscraper problems. Top results are in 2D and 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	152	2.01𝑒−7	×	×	×	×	16	4.20𝑒−8	15	3.93𝑒−8
100	×	×	×	×	×	×	26	2.63𝑒−7	24	4.86𝑒−7
200	×	×	×	×	×	×	39	9.50𝑒−7	37	1.90𝑒−6
300	×	×	×	×	×	×	47	2.77𝑒−6	44	2.64𝑒−6
10	19	4.57𝑒−12	16	2.40𝑒−12	17	1.86𝑒−12	8	7.08𝑒−13	7	1.66𝑒−11
15	190	1.07𝑒−8	×	×	×	×	13	9.91𝑒−9	25	8.92𝑒−9
20	132	2.57𝑒−8	×	×	×	×	11	5.13𝑒−9	20	6.21𝑒−9
30	×	×	×	×	×	×	14	6.91𝑒−8	13	8.84𝑒−8