In the design of ODE/DAE software the robustness of the internal controls is of great importance to the users. Not only will it influence the efficiency in computation but also the quality of the overall solution. The design of the control algorithms must be analysed carefully in order to obtain succesfull implementations. Software design is moving from art to science and the availability of software that is designed for testing of ODE-solvers has fascilitated the analysis of different algorithms in unified environments. Examples of control algorithms in use in state of the art software that lead to chaotic behaviour will be presented and compared to examples of more robust algorithms. The examples are analysed and numerical tests will be presented.

MINISIMPOSIUM SESSION: 17. Software isues in ODEs