Specification and Efficient Computation of Passage-Time Distributions in GPA

We present a significant extension to the Grouped PEPA Analyser (GPA) tool. We have augmented the tool with the ability to specify complex passage-time distributions with the Unified Stochastic Probes formalism and implemented efficient fluid analysis techniques to compute the distributions. The extension incorporates immediate signalling and weighted passive rates and permits two classes of passage time, namely global and individual passage times, to be computed. We summarise how the different classes of passage-time query can be expressed using the Unified Stochastic Probe formalism and present some results from probed GPA models.