An Adaptive Nonconforming Finite Element Algorithm for Laplace Eigenvalue Problem

Table 2

The 1st and 6th eigenvalues obtained by two algorithms on slit domain with 𝐻=√2/16.

𝑘	𝑙^∗	dof𝑘,𝑙^∗	𝜆𝑘,ℎ𝑙∗	CPU𝑘,𝑙^∗(s)	𝑙	dof𝑘,𝑙	𝜆^ℎ𝑙𝑘	CPU𝑘,𝑙(s)
1	5	5229	8.329697	0.43	5	5229	8.329697	0.25
1	10	17488	8.361012	1.33	10	17491	8.361012	0.79
1	15	64863	8.368891	5.14	15	64863	8.368891	2.90
1	20	249713	8.370756	23.4	20	249713	8.370756	12.9
1	23	569429	8.371082	61.5	23	569429	8.371082	31.2
1	24	—	—	—	24	748279	8.371148	44.0
6	5	8733	30.39428	0.69	5	8721	30.39422	0.41
6	10	35253	30.50367	3.21	10	35212	30.50363	1.68
6	15	141116	30.52867	16.2	15	140930	30.52866	8.20
6	19	426746	30.53371	58.8	19	426194	30.53371	28.9
6	20	566328	30.53432	82.6	20	565526	30.53431	39.1
6	21	—	—	—	21	743261	30.53464	54.9