The Gauss-Seidel and Successive Over Relaxation (SOR) Methods for the Laplace Finite Difference Equation:
Omega is the relaxation parameter. If omega is 1.0, the Gauss-Seidel method is implemented. Choosing the optimal omega yields the maximum convergence rate in the SOR method.

Try experimenting with omega by adjusting it as the iterations proceed. Values of omega between 0.0 and 1.0 correspond to "under relaxation". How does under relaxation affect the convergence rate?