This m-file explores the transient response of a single node P, when adjacent nodes E and W are held fixed. There are 3 levels of discretization:

• no discretization - an analytical solution (cosine series) is evaluated and history phi_P(t) is found.
• The spatial domain is discretized so that fluxes at volume boundaries are proportional to (phi_P - phi_E)/dx_e etc. Time is still continuous in the plotted analytical solution.
• Both time and space are discretized. Plot shows the value phi_P(dt) for different step sizeds dt.