The PRISM language can be used to describe three types of probabilistic models:
discrete-time Markov chains (DTMCs), continuous-time Markov chains (CTMCs)
and Markov decision processes (MDPs).
To indicate which type is being described, a PRISM model includes one of the keywords
dtmc
, ctmc
or mdp
.
This is typically at the very start of the file (as in Example 1),
but can actually occur anywhere in the file (except inside modules and other declarations).
The keywords probabilistic
, stochastic
and nondeterministic
can be used as alternatives for dtmc
, dtmc
and mdp
, respectively.
If no such model type declaration is included, the model is by default assumed to be an MDP.