Approximation of the pth Roots of a Matrix by Using Trapezoid Rule

Table 3

Comparison absolute error for different numbers of points for different matrices.

No. of points	Schur decomposition	Eigenvalue decomposition	Hessenberg decomposition
2	4.235476891477593	3.617696711330309	9.018271218363070
4	7.642822555078070	2.268548808462573	85.569768110351674
8	6.509731621793472	16.059530670734521	0.951463218971532
16	0.035910610643974	0.342929548483509	0.001435059307873
32	0.000002770887073	0.342929548483509	0.000000210760699
64	0.000000000000375	0.003429295484835	0.000000000000349
128	0.000000000000002	0.003429295484835	0.000000000000002
256	0.000000000000002	0.003429295484835	0.000000000000002
512	0.000000000000004	0.003429295484835	0.000000000000003
1024	0.000000000000001	0.000342929548484	0.000000000000000