adding indexes and solving 2nd order ode

The project is simple! I have a nice working program. I need to add a function to the program which is 2nd order ode. I have arrays p2, u2 1*101 valued as can be checked from attaches. I need to add a second order differential equation to an existing program I need to find f. e_2*f_xx = p2-p0 where p0 say 0 for [login to view URL] is like a cycle. f should be inside u2 , u2 should be inside p2, p2 should be used for f. The boundary conditions for f are f(x=0) = f(x=1) = 0. f is coming into play in an if condition in the main program when t-1<x<t where x represents space and t represents time. f is called constriction function to be found.