A PDE2D program is created by the GUI, or the Interactive Driver, and all documentation, including examples, is available on-line. All the user has to do is answer a series of questions about the region, partial differential equations and boundary conditions, and select solution method and graphical output options. The Interactive Driver or GUI automatically writes a FORTRAN program, based on the user's answers, which is then compiled and linked to the PDE2D library routines it calls. However, the user does NOT need to be a FORTRAN programmer to use PDE2D ; for most problems, he/she only needs to know how to write basic FORTRAN expressions such as X*Y+Z. Neverthess, the PDE2D user has all the flexibility of FORTRAN at his/her disposal; for example, any PDE or boundary condition coefficient can be defined by a user-written FORTRAN function subprogram, and it is very easy to add calls to user-supplied subroutines to plot or otherwise postprocess the PDE2D solution. In fact, PDE2D now automatically outputs the solution to a MATLAB m-file, from which you have easy access to all of MATLAB's graphical abilities.
The GUI can only be used to access the PDE2D collocation methods, so if you have a complex 2D region you must use the Interactive Driver interface, to access the Galerkin method. But for 0D and 1D problems, and for problems in a wide range of simple 2D and 3D regions, you can set up your problem using the GUI in an exceptionally short amount of time.
The author of PDE2D, Granville Sewell, has written 4 numerical analysis books, and has been working continuously on this program for over 40 years.