h

$l^{\infty }$ -error

order

$l^2$ -error

order

$\frac{1}{8}$

1.11e−03

−

5.55e−04

−

$\frac{1}{16}$

6.45e−05

4.10

3.23e−05

4.10

$\frac{1}{32}$

3.98e−06

4.02

1.99e−06

4.02

$\frac{1}{64}$

2.48e−07

4.00

1.24e−07

4.00

$\frac{1}{128}$

1.55e−08

4.00

7.76e−09

4.00