3.4 Quantity Server

During simulation a large amount of physical quantities needs to be handled. These quantities serve as input for certain models or are created as output by other models. Quantities are for instance the electron current density, the electric field, or the dielectric permittivity.

The demands on the classes describing the quantities are manifold and the system which manages quantities must fulfill several requirements:

• A powerful, easy to use interface to enable a straight forward and consistent way to use and access information stored in the quantities. The functionality of the interface must be appropriate for handling of all situations in every module of the simulator.
• The access to values must be very fast.
• The management of quantities as well as the communication with the input libraries must be completely encapsulated.
• The list of quantities which are needed by the solver module of Minimos-NT and contribute to the system matrix have to be automatically created depending on the equation set used.

Therefore, a quantity server has been implemented in Minimos-NT which makes use of several hierarchically structured classes. The classes have been designed for several different application fields and are explained in the following sections.

The design of the quantity server is shown in Fig. 3.4. The main module is the quantity module. It manages all quantities and controls access to their information. The Quantity List Assembly module is responsible for creating appropriate lists of quantities which are needed for the physical models. The IO module contains modules which encapsulates functions and libraries needed for input/output. In addition modules are implemented which handle the PIF-Libraries and a native file format.

Figure 3.4: The structure of the quantity server.

The application interface is formed by a set of global functions and by class interface functions provided by the quantity server. The global functions are mainly used for initialization.