Software Requirements

Since the parallel particle framework is a library to be used by developers of large physics problems where correctness and efficiency is crucial, the library must have the following attributes.

• Ease of Use: PPF must provide a simple interface that is intuitive to a developer with no experience in parallel computing. All code dealing with parallelization technology must be transparent to the developer.
• Efficiency: Large scale problems running billions of iterations on thousands of nodes can continuously accumulate small efficiency problems eventually leading to a significant increase to the running time of the problem. For this reason the PPF must be extremely efficient in message passing and performance.
• Stability: Problems run by radiation transport particle packages may take days to complete. For this reason it is imperative that PPF be stable by ensuring no runtime errors nor memory leaks. This is more important for PPF than other small scale applications because a faulty run can cost the developers days at a time. In the advent of a crash PPF should be able to resume operation at the last time step completed.
• Scalability: The platforms used for large scale radiation transport problems are continuously growing in size, therefore in order for PPF to be of use in the future it must be scalable to an arbitrary number of nodes efficiently.
• Longevity: PPF must ensure the integrity of all its requirements for the life of the package which implements it. The KULL framework is expected to be a 20 year code, the PPF should retain functionality for at least this time period.