and side function, and nonhomogeneous
      Dirichlet boundary conditions.   The state variable
      U(T,X,Y) is then constrained by:
      <pre>
        Ut - ( Uxx + Uyy ) + K(x,y,t) * U = F(x,y,t)  in the region
                                        U = G(x,y,t)  on the boundary
                                        U = H(x,y,t)  at initial time TINIT.
      </pre>
    </p>

    <p>
      To specify the right hand side function F(x,y,t), the linear
      coefficient K(x,y,t), the boundary condition f