Structure of Iode

For users who like to look under the hood, we now provide some information on the structure of Iode. We encourage users to modify Iode and create new modules.

Figure D.1 breaks Iode down into its constituent modules. Each module occurs as an m-file with the same name. For example, dfgui in the figure means the file dfgui.m that comes as part of the Iode package. If you type doctool('guidoc') at the Matlab prompt, you'll see Figure D.1 in a Matlab figure, and if you click on the name of a module, its help message will appear in Matlab's help window. This will give you an idea of what Iode's modules do and how they work together.

There are two kinds of module. The first kind are the GUI modules and auxiliaries, providing the graphical user interface. The second (and main) kind are the mathematical modules, which actually perform the calculations needed to solve the differential equations numerically, and calculate the Fourier coefficients numerically, and so on.

The mathematical modules euler.m and rk.m are particularly instructive -- they implement the Euler and Runge-Kutta methods for solving a first order ODE. You can implement different solver methods yourself, as outlined in Appendix C.

In order to develop a better understanding of what the various modules do, you can look at the file doc.txt. Together with Figure D.1, it should give you a rather complete picture of the structure of Iode. Another useful file to look at is sample.m, which contains the transcript of a short Matlab session that shows how to use the direction fields module and numerical solvers without resorting to any menus.

Any manual can only take you so far. If you have followed this manual up to this point, you are ready to go exploring on your own. Good luck, and have fun!

図 D.1: Relationships between the most important modules of the GUI version of Iode.