Hi everyone. I have the following system of PDE's: ut = vx vt = (-3)*ux + 4*vx, with initial conditions u(x,0) = sin (x), v(x,0) = 0. I am only considering the region 0<x<2*pi and 0<t<4*pi. The solution is assumed to be periodic in space. Using MATLAB, I want to discretize in space using a central difference quotient, and then apply the 4:th order Runge-Kutta method in time. Being new to both numerical methods as well as MATLAB I have been unable to manage this task. I found this m-file for system of ODE's: http://matlabdb.mathematik.uni-stuttgart.de/runge_kutta4.m?MP_ID=405 I tried modifying it to suit my purpose but it wouldn't work. Is there an easy way to modify it when I include the space discretization? Or does anyone have a better idea? Thanks for taking a look.