Table 1 \(L^{2}\)-norm and convergence rate when \(\beta =\gamma =0.3,0.5, 0.8\) and \(\tau =h\)

1/2⁴

3.7106e−05

–

3.7573e−05

–

3.9845e−05

–

1/2⁵

1.0136e−05

1.8722

1.0213e−05

1.8793

1.0749e−05

1.8902

1/2⁶

2.6712e−06

1.9239

2.6777e−06

1.9313

2.8043e−06

1.9385

1/2⁷

6.9103e−07

1.9507

6.8902e−07

1.9584

7.1849e−07

1.9646

1/2⁸

1.7735e−07

1.9621

1.7567e−07

1.9717

1.8242e−07

1.9777