def pdfa(start: State,
label: Callable[[State], Letter],
transition: Callable[[State, Action], State],
env_dist: EnvDist = None,
inputs: Alphabet = None,
env_inputs: Alphabet = None,
outputs: Alphabet = None) -> PDFA:
"""Main entrypoint for construction a Probablistic Automaton."""
if inputs is None:
inputs = SupAlphabet()
if outputs is None:
outputs = {True, False}
if env_inputs is None and env_dist is None:
env_inputs = {None}
env_dist = uniform(env_inputs)
inputs = ProductAlphabet(inputs, env_inputs)
return PDFA(
env_dist=env_dist,
dfa=DFA(
start=start,
label=label,
inputs=inputs,
outputs=outputs,
transition=transition,
),
)
def randomize(dyn: DFA) -> PDFA:
"""Lifts a DFA into a PDFA where original inputs are applied
uniformly at random.
"""
return PDFA(
dfa=attr.evolve(
dyn,
inputs=ProductAlphabet({None}, dyn.inputs),
transition=lambda s, c: dyn._transition(s, c[1]),
),
env_dist=uniform(dyn.inputs),
)
def lift(dyn: Union[DFA, PDFA]) -> PDFA:
"""Lifts a DFA into a deterministic PDFA."""
if isinstance(dyn, PDFA):
return dyn
return PDFA(
dfa=attr.evolve(
dyn,
inputs=ProductAlphabet(dyn.inputs, {None}),
transition=lambda s, c: dyn._transition(s, c[0]),
),
env_dist=uniform({None}),
)