There are 3 script files (programs) heat3.m, heat4.m, and heat5.m

     heat3 integrates the heat equation on [0, 10] with Dirichlet
boundary conditions. User must provide an mfile f.m for the initial data.
It must be array smart.  right.m and left.m are function mfiles (to be 
provided by user) which give the data at x = 0 and at x = 10 for the
boundary conditions.  When the boundary conditions are u = 0 at 
x = 0, or u = 0 at x = 10,  right.m and left.m should be y = 0.  

     heat4 integrates the heat equation on [0,10] with homogeneous
Neumann boundary conditions. f.m is again the initial data. q.m is
the source function (right hand side) for this program.

     heat5 solves the heat equation on [0,10] with different diffusion
constants on [0,5] and [5,10]. f.m is again the initial data.