def get_equivalent_restricted_formula(self):
''' Return a equivalent formula in the restricted syntax.
This method returns a formula that avoids "and", "implies", "A", "F",
and "R" and that is equivalent to this formula.
:param self: this formula
:type self: E
:returns: a formula that avoids "and", "implies", "A", "F", and "R" and
that is equivalent to this formula
:rtype: StateFormula
'''
p_formula = self.subformula(0)
sf0 = p_formula.subformula(0).get_equivalent_restricted_formula()
if (isinstance(p_formula, CTLS.X)):
return EX(sf0)
if (isinstance(p_formula, CTLS.F)):
return EU(True, sf0)
if (isinstance(p_formula, CTLS.G)):
return EG(sf0)
sf1 = p_formula.subformula(1).get_equivalent_restricted_formula()
if (isinstance(p_formula, CTLS.U)):
return EU(sf0, sf1)
if (isinstance(p_formula, CTLS.R)):
neg_sf1 = LNot(sf1)
neg_sf0 = LNot(sf0)
return Or(EU(sf1, Not(Or(neg_sf0, neg_sf1))), EG(sf1))
raise TypeError('%s is not a CTL formula' % (self))
def get_closure(formula):
closure=set()
T=[formula]
Lang=sys.modules[formula.__module__]
while len(T)>0:
phi=T.pop()
if hash(phi) not in [hash(o) for o in closure]:
closure.add(phi)
T.append(LNot(phi))
if isinstance(phi,CTLS.X):
T.append(phi.subformula(0))
else:
if (isinstance(phi,CTLS.Not) and
isinstance(phi.subformula(0),CTLS.X)):
sf=phi.subformula(0).subformula(0)
T.append(Lang.X(LNot(sf)))
else:
if isinstance(phi,CTLS.Or):
T.append(phi.subformula(0))
T.append(phi.subformula(1))
else:
if isinstance(phi,CTLS.U):
T.append(phi.subformula(0))
T.append(phi.subformula(1))
T.append(Lang.X(phi))
else:
if not (isinstance(phi,CTLS.Not) or
isinstance(phi,CTLS.AtomicProposition) or
isinstance(phi,CTLS.Bool)):
raise TypeError('expected a LTL path formula ' +
'restricted to "or", "not", '+
'"U" and "X", got %s' % (phi))
return closure
def modelcheck(kripke, formula, parser=None, F=None):
''' Model checks any LTL formula on a Kripke structure.
This method performs LTL model checking of a formula on a given
Kripke structure.
:param kripke: a Kripke structure.
:type kripke: Kripke
:param formula: the formula to model check.
:type formula: a type castable in a LTL.Formula or a string representing
a LTL formula
:param parser: a parser to parse a string into a LTL.Formula.
:type parser: LTL.Parser
:param F: a list of fair states
:type F: Container
:returns: a list of the Kripke structure states that satisfy the formula.
'''
if isinstance(formula, str):
if parser is None:
parser = Parser()
formula = parser(formula)
if not (isinstance(formula, CTLS.A)):
raise TypeError('expected a LTL state formula, got {}'.format(formula))
if not isinstance(kripke, Kripke):
raise TypeError('expected a Kripke structure, got {}'.format(kripke))
try:
p_formula = LNot(formula.subformula(0))
p_formula = p_formula.get_equivalent_restricted_formula()
if F is not None:
kripke = kripke.clone()
fair_label = kripke.label_fair_states(F)
p_formula = p_formula.get_equivalent_non_fair_formula(fair_label)
p_formula = And(fair_label, p_formula)
return set(kripke.states()) - _checkE_path_formula(kripke, p_formula)
except TypeError:
raise TypeError('expected a LTL formula, got {}'.format(formula))
def modelcheck(kripke,formula,F=None):
if not (isinstance(formula,CTLS.A)):
raise TypeError('expected a LTL state formula, got %s' % (formula))
if not isinstance(kripke,Kripke):
raise TypeError('expected a Kripke structure, got %s' % (kripke))
try:
p_formula=LNot(formula.subformula(0)).get_equivalent_restricted_formula()
if F!=None:
kripke=kripke.copy()
fair_label=kripke.label_fair_states(F)
p_formula=p_formula.get_equivalent_non_fair_formula(fair_label)
p_formula=And(fair_label,p_formula)
return set(kripke.states())-checkE_path_formula(kripke,p_formula)
except TypeError:
raise TypeError('expected a LTL formula, got %s' % (formula))
def _get_closure(formula):
closure = set()
T = [formula]
Lang = sys.modules[formula.__module__]
while len(T) > 0:
phi = T.pop()
if phi not in closure:
closure.add(phi)
T.append(LNot(phi))
if isinstance(phi, CTLS.X):
T.append(phi.subformula(0))
else:
if (isinstance(phi, CTLS.Not)
and isinstance(phi.subformula(0), CTLS.X)):
sf = phi.subformula(0).subformula(0)
T.append(Lang.X(LNot(sf)))
else:
if isinstance(phi, CTLS.Or):
for sf in phi.subformulas():
T.append(sf)
else:
if isinstance(phi, CTLS.U):
T.append(phi.subformula(0))
T.append(phi.subformula(1))
T.append(Lang.X(phi))
else:
if not (isinstance(phi, CTLS.Not)
or isinstance(phi, CTLS.AtomicProposition)
or isinstance(phi, CTLS.Bool)):
raise TypeError('expected a LTL path ' +
'formula restricted to ' +
'"or", "not", ' +
'"U" and "X", got ' +
'{}'.format(phi))
return closure
def get_equivalent_non_fair_formula(self, fairAP):
p_formula = self.subformula(0)
sf0 = p_formula.subformula(0).get_equivalent_non_fair_formula(fairAP)
if (isinstance(p_formula, CTLS.X)):
return EX(And(sf0, fairAP))
if (isinstance(p_formula, CTLS.F)):
return EU(True, And(sf0, fairAP))
if (isinstance(p_formula, CTLS.G)):
return EG(And(sf0, fairAP))
sf1 = p_formula.subformula(1).get_equivalent_non_fair_formula(fairAP)
if (isinstance(p_formula, CTLS.U)):
return EU(sf0, And(sf1, fairAP))
if (isinstance(p_formula, CTLS.R)):
neg_sf1 = LNot(sf1)
neg_sf0 = LNot(sf0)
return Or(EU(sf1, And(Not(Or(neg_sf0, neg_sf1))), fairAP),
EG(And(sf1, fairAP)))
raise TypeError('%s is not a CTL formula' % (self))
def _build_atoms(K, closure):
A = []
for state in K.states():
A.append(_TableuAtom(state))
# this is to avoid issues with the "not X" case
cl_list = sorted(list(closure),
key=(lambda a: a.height
if not (isinstance(a, CTLS.Not) and isinstance(
a.subformula(0), CTLS.X)) else a.height - 1))
for phi in cl_list:
Lang = sys.modules[phi.__module__]
if phi != Lang.Not(True) and phi != Lang.Bool(False):
neg_phi = LNot(phi)
A_tail = []
if isinstance(phi, CTLS.Bool):
for atom in A:
atom.add(phi)
else:
if isinstance(phi, CTLS.AtomicProposition):
for atom in A:
if phi in K.labels(atom.state):
atom.add(phi)
else:
atom.add(neg_phi)
if (isinstance(phi, CTLS.Or)):
sf = phi.subformulas()
for atom in A:
if sum([f in atom for f in sf]):
atom.add(phi)
else:
atom.add(neg_phi)
if (isinstance(phi, CTLS.Not)
and isinstance(phi.subformula(0), CTLS.X)):
sf = phi.subformula(0).subformula(0)
for atom in A:
if phi.subformula(0) not in atom:
if phi not in atom:
new_atom = atom | set([phi, Lang.X(LNot(sf))])
A_tail.append(new_atom)
atom.add(phi.subformula(0))
else:
atom.add(Lang.X(LNot(sf)))
if isinstance(phi, CTLS.U):
sf = phi.subformulas()
for atom in A:
if (sf[1] in atom):
atom.add(phi)
A_tail.append(atom | set([Lang.X(phi)]))
else:
if (sf[0] in atom):
A_tail.append(atom | set([phi, Lang.X(phi)]))
atom.add(neg_phi)
atom.add(Lang.Not(Lang.X(phi)))
A.extend(A_tail)
for atom in A:
if phi not in atom and neg_phi not in atom:
A.append(atom | set([phi]))
atom.add(neg_phi)
return A
def build_atoms(K, closure):
A = []
for state in K.states():
A.append(TableuAtom(state))
for phi in sorted(list(closure), key=lambda a: a.height):
Lang = sys.modules[phi.__module__]
if phi != Lang.Not(True) and phi != Lang.Bool(False):
neg_phi = LNot(phi)
A_tail = []
if isinstance(phi, CTLS.Bool):
for atom in A:
atom.add(phi)
else:
if isinstance(phi, CTLS.AtomicProposition):
for atom in A:
if phi in K.labels(atom.state):
atom.add(phi)
else:
atom.add(neg_phi)
if (isinstance(phi, CTLS.Or)):
sf = phi.subformulas()
neg_sf = [LNot(p) for p in sf]
for atom in A:
if (sf[0] in atom or sf[1] in atom):
atom.add(phi)
else:
atom.add(neg_phi)
if (isinstance(phi, CTLS.Not)
and isinstance(phi.subformula(0), CTLS.X)):
sf = phi.subformula(0).subformula(0)
for atom in A:
if phi.subformula(0) not in atom:
if phi not in atom:
new_atom = atom | set([phi, Lang.X(LNot(sf))])
A_tail.append(new_atom)
atom.add(phi.subformula(0))
else:
atom.add(Lang.X(LNot(sf)))
if isinstance(phi, CTLS.U):
sf = phi.subformulas()
neg_sf = [LNot(p) for p in sf]
for atom in A:
if (sf[1] in atom):
atom.add(phi)
A_tail.append(atom | set([Lang.X(phi)]))
else:
if (sf[0] in atom):
A_tail.append(atom | set([phi, Lang.X(phi)]))
atom.add(neg_phi)
atom.add(Lang.Not(Lang.X(phi)))
A.extend(A_tail)
for atom in A:
if phi not in atom and neg_phi not in atom:
A.append(atom | set([phi]))
atom.add(neg_phi)
return A
