4.1 Key Demands on the Assembly Module

From the perspective of a simulator, which can be an arbitrary code requiring assembling and solving of linear equation systems, the key demands on the assembly module can be summarized as follows:

1. Application Programming Interface (API) providing methods for:
   • Adding values to the equation system.
   • Deleting equations.
   • Invoking the solving process.
   • Retrieving the solution.
2. Usability.
3. Performance.
4. Conditioning of the equation system for solving.
5. Handling of real-valued and complex-valued equation systems.

Hence, the assembly module employed by the simulator shall be responsible for storing the contributions of the various physical models of the simulator. In addition, for the sake of consistence and simplicity the API shall embrace also the interface to the solver module. This allows also the conditioning of the assembled equation system in order to improve its solvability.

By providing these abstracted features the simulator can be designed and implemented in a very efficient way. This has the following reasons:

• The model developer is able to focus on the model implementation only, because the respective contributions can be conveniently added without taking any aspects regarding the implementation (allocation, access, deallocation etc.) of the assembly module into account.
• The further development of the simulator is not limited by the assembly module in case this module is generally designed and does not impose restrictions for its application.