An Adaptive Nonconforming Finite Element Algorithm for Laplace Eigenvalue Problem

Table 1

The 1st and 5th eigenvalues obtained by two algorithms on 𝐿-shaped domain with 𝐻=√2/16.

𝑘	𝑙^∗	dof𝑘,𝑙^∗	𝜆𝑘,ℎ𝑙∗	CPU𝑘,𝑙^∗(s)	𝑙	dof𝑘,𝑙	𝜆^ℎ𝑙𝑘	CPU𝑘,𝑙(s)
1	5	6615	9.624308	0.43	5	6615	9.624308	0.26
1	10	28350	9.636503	1.83	10	28350	9.636503	0.99
1	15	122122	9.638997	9.27	15	122122	9.638997	5.17
1	19	387527	9.639505	35.6	19	387527	9.639505	19.3
1	20	520999	9.639556	52.0	20	520999	9.639556	26.6
1	21	—	—	—	21	692323	9.639608	38.2
5	5	8319	31.83478	0.62	5	8319	31.83478	0.35
5	10	38601	31.89705	3.07	10	38601	31.89705	1.75
5	15	171591	31.90928	17.1	15	171591	31.90928	9.79
5	18	414327	31.91127	47.9	18	414327	31.91127	26.7
5	19	550331	31.91156	68.6	19	550331	31.91156	37.0
5	20	—	—	—	20	743563	31.91187	53.0