def generate_counter_example(fsm,
problem,
solver,
k,
descr="BMC counter example"):
"""
Generates a counter example for `problem` evaluated against `fsm` as
identified by `solver` (problem has a length `k`) but prints nothing.
.. note::
If you are looking for something more advanced, you might want to look
at :func:`pynusmv.be.encoder.BeEnc.decode_sat_model` which does the same
thing but is more complete.
:param fsm: the FSM against which problem was evaluated
:param problem: the SAT problem used to identify a counter example
:param solver: the SAT solver that identified a counter example
:param k: the length of the generated problem (length in terms of state)
:param descr: a description of what the generated counter example is about
:raises ValueError: whenever the problem or the solver is None or when the
problem bound `k` is negative.
"""
if problem is None:
raise ValueError("a problem must be given")
if solver is None:
raise ValueError("a solver must be given")
if k < 0:
raise ValueError("the problem bound `k` must be non negative")
ptr = _bmc.Bmc_Utils_generate_cntexample(
fsm.encoding._ptr, solver._as_SatSolver_ptr(), problem._ptr, k, descr,
glob.master_bool_sexp_fsm().symbols_list._ptr)
return Trace(ptr)
