EPODE

Interface facilities

In order

to create a database of ODE problems on which the application works (which can be seen also as a database of application examples),
to create an interface with other software products for solving differential equations;
to work on a previous saved problem,

problem input/output facilities must be stipulated. It is preferable to use a general format for files; for example, we can use text files.

In order to

correct the user typing errors,
remember previous defined expressions and values,

an user-interactive, permanently ready, interface must be created. For simplification of the search procedure, the problem variables, the problem equations, the integration values, and the initial values can be described in different control panels.

Example.

The user can store a defined problem and reload it after some time. In this manner, a problem database can be created. In EpODE's directory ODES, one can be find approximately 100 problems (including those from STIFF DETEST for which an approximate solution has been calculated in test stage (a successful solving of a problem permits to the user to save the problem, the method, the computing parameters, and the display parameters for the results in a 'Session', which can be reloaded in order to review the old results).

The item menu 'Problem' conduct to the control panels for describing a new problem, loading one or saving the current described one (the submenu items are; 'New problem', 'Load problem', 'Save problem', 'Show control panels' for 'Dimension and variables', 'Equations', 'Initial values', 'Integration interval', 'Problem properties'). Each control panel can be accessed separately. Shortcomings are possible using the toolbar.

Variable and expression checks are made for each user-input. The input status ('Complete' or not) is also showed.

In the computer-expert mode, the user can obtain the approximate solution immediately after the problem description. The solving method is automatically selected.