How it works

The equations are evolved entirely using the method of lines thorn. So all we have to provide (for the evolution) is a method of calculating the right hand side of equation (F8.2) and boundary conditions. The boundary conditions are standard from wavetoy itself. The right hand side is calculated using second order centred finite differences.

To be compatible with the method of lines thorn we must let it know that the GFs $(\phi, \Pi, \Phi^j)$ exist and where they are stored. They should all have at least two time levels (although the addition of extra time levels may not cause problems it's just wasting space). The GFs corresponding to the right hand sides must also be registered with the MoL thorn. These should only have one time level. MoL is informed of the existence of these grid functions through the accumulator parameters and the aliased functions.