PRISM-games is an extension of PRISM for probabilistic model checking of stochastic multi-player games.

See the website and read the papers for more information.

PRISM is a probabilistic model checker, a tool for formal modelling and analysis of systems that exhibit random or probabilistic behaviour. It has been used to analyse systems from many different application domains, including communication and multimedia protocols, randomised distributed algorithms, security protocols, biological systems and many others.

Example PRISM graph PRISM can build and analyse several types of probabilistic models:

  • discrete-time Markov chains (DTMCs)
  • continuous-time Markov chains (CTMCs)
  • Markov decision processes (MDPs)
  • probabilistic automata (PAs)
  • probabilistic timed automata (PTAs)
plus extensions of these models with costs and rewards.

Models are described using the PRISM language, a simple, state-based language. PRISM provides support for automated analysis of a wide range of quantitative properties of these models, e.g. "what is the probability of a failure causing the system to shut down within 4 hours?", "what is the worst-case probability of the protocol terminating in error, over all possible initial configurations?", "what is the expected size of the message queue after 30 minutes?", or "what is the worst-case expected time taken for the algorithm to terminate?". The property specification language incorporates the temporal logics PCTL, CSL, LTL and PCTL*, as well as extensions for quantitative specifications and costs/rewards.

PRISM incorporates state-of-the art symbolic data structures and algorithms, based on BDDs (Binary Decision Diagrams) and MTBDDs (Multi-Terminal Binary Decision Diagrams) [KNP04b, Par02]. It also includes a discrete-event simulation engine, providing support for approximate/statistical model checking, and implementations of various different analysis techniques, such as quantitative abstraction refinement and symmetry reduction.

PRISM is free and open source, released under the GNU General Public License (GPL).

To cite PRISM, please use the most recent tool paper, from CAV'11:

Latest News

February 2016: We are delighted to announce that PRISM has again been selected to participate in Google Summer of Code. Contribute to PRISM and get paid for it! More details here and a news item here.
November 2015: We are pleased to report that PRISM has now been downloaded more than 50,000 times. Thanks for your support!
October 2015: Version 2.0 of PRISM-games is out, featuring new reward properties, multi-objective strategy synthesis and assume-guarantee reasoning. More info here.
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