USER-DEFINED SYSTEMS

This section describes how to create a user-defined system by deriving a class from the abstract class System. There are three mandatory steps:

1. Declare a new class from System. Grant public inheritance access.

         class UserSystem : public System
          {
           ...
          };

2. Write a constructor for the derived class that constructs an object of the class System by means of an initialization list. Make sure that the constructor calls InitSS at the end of the body. The constructor may be used to initialize the parameters of the system.

          UserSystem :: UserSystem() : 
          System(step, species, rates, input_species, output_rate)
           {
            ...
            InitSS();
           }

Remember that the parameters of the constructor of System are

3. Provide the method EvaluateSystem. This method should evaluate the velocities and the derivatives of the concentrations (i.e. the differential equations of the system). Here is where the system is actually defined

          void UserSystem :: EvaluateSystem(void)
           {
            // Evaluation of the velocities
            v[0]      = ...;
            ...
            v[numv-1] = ...;

            // Differential equations
            dc[0]      = ...;
            ...
            dc[numc-1] = ...;
           }

In addition, the user may want to define additional data types and methods that support the constructor and EvaluateSystem, and that provide additional functionality. For example, methods may be defined that evaluate a rate equation from a set of parameters and concentrations.

Copyright © 2003-2013 Antonio Sánchez Torralba
Last modified:
Monday, 04-Mar-2013 11:58:25 CET