bigg.m is a function mfile to be used as a wave profile.

     program robin.m calculates the reflection of the incident wave
     profile bigg.m from the left boundary x = 0 with the Robin boundary
     condition.

     programs trans.m  calculates the reflection and transmission 
     of an incident wave wave profile, given by bigg.m.
    
     
     program wave1.m integrates the linear wave equation on [0,10]
     with u = 0 at x = 0 and x = 10.  The function files f.m and 
     g.m are the initial data.

     program wave2.m integrates a nonlinear wave equation on [0,10]
     with boundary conditions u = 0 at x = 0 and x = 10. It uses 
     the files  
              newton.m   l.m    dl.m

     User must provide mfiles f.m and g.m for the initial data. 
     wave2.m calls on the script file newton.m to advance each time
     step by solving a nonlinear system. l.m and dl.m are function
     mfiles, used by newton.m, which specify the nonlinearity.  
     Currently the nonlinearity is   gamma * u^3  where gamma
     is a scalar chosen at run time.

     program film_reflect is a script file which makes a 40 frame movie
     of the reflection of the incident wave profile, given in bigg.m, 
     with boundary condition u = 0 at the left boundary x = 0.