7 Neumann 3 Dirichlet boundary algorithm

1D Gauge Wave, $\hat W$ system, $\ell_\infty$ error in $g_{xx}$ convergence plots.

The convergence rate for the error in $g_{xx}$, measured at t=50 and t=500, for 7 Neuman 3 Dirichlet boundary algorithm, is:

$${\tilde c_r^{(50)}} = 1.804, {\tilde c_r^{(500)}} = 2.228$$ (19)