Propagating Pulse |

**a**,**b**,**eta**are parameters of the equation.**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*increases the speed at the cost of faithfulness to the original equations.^{-2}**amp**is the amplitude of a sinusoidal forcing at one corner with frequency*0.5***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.**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 h ^{2}=0.025*.