A Twisted Block Tangential Filtering Decomposition Preconditioner

Table 7

Results for Case 5: anisotropic layers. 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	99	5.88𝑒−8	53	9.38𝑒−9	47	1.61𝑒−8	11	2.44𝑒−8	10	3.78𝑒−8
100	190	6.73𝑒−7	76	6.22𝑒−8	72	1.22𝑒−8	17	6.23𝑒−7	16	7.38𝑒−8
200	×	×	110	3.30𝑒−8	103	3.45𝑒−8	29	2.30𝑒−6	27	1.05𝑒−7
300	×	×	136	7.95𝑒−9	127	2.08𝑒−8	40	1.04𝑒−7	37	1.22𝑒−7
20	27	1.43𝑒−7	24	2.22𝑒−8	22	2.66𝑒−8	10	1.43𝑒−8	9	1.22𝑒−8
30	34	2.55𝑒−7	27	3.31𝑒−8	26	3.97𝑒−8	11	4.87𝑒−8	10	5.98𝑒−8
40	40	8.14𝑒−7	28	1.98𝑒−8	29	4.97𝑒−8	11	1.75𝑒−7	11	7.12𝑒−8