Notes

1. a, b, eta are parameters of the equation.
2. delta is a "small" parameter that sets when a simplified iteration scheme is used that is good only for small values of one of the fields (the scheme is used when the value is less than delta). Increasing delta to 10^-2 increases the speed at the cost of faithfulness to the original equations.
3. amp is the amplitude of a sinusoidal forcing at one corner with frequency 0.5
4. speed is a benign way of increasing the speed at the cost of jerkiness of the plotting: the iteration is done speed times between each plot update.
5. Plot type 1 shows the u variable and 2 the v variable.

The system size is 32 along each edge. The mesh size h for the finite difference code is 0.5 and the time step dt=0.1 h²=0.025.