def get_relevant_facts(proposition, assumptions=(True, ), context=global_assumptions, use_known_facts=True, exprs=None, relevant_facts=None): newexprs = set() if not exprs: keys = proposition.atoms(AppliedPredicate) # XXX: We need this since True/False are not Basic keys |= Tuple(*assumptions).atoms(AppliedPredicate) if context: keys |= And(*context).atoms(AppliedPredicate) exprs = {key.args[0] for key in keys} if not relevant_facts: relevant_facts = set([]) if use_known_facts: for expr in exprs: relevant_facts.add(get_known_facts_cnf().rcall(expr)) for expr in exprs: for fact in fact_registry[expr.func]: newfact = fact.rcall(expr) relevant_facts.add(newfact) newexprs |= set( [key.args[0] for key in newfact.atoms(AppliedPredicate)]) return relevant_facts, newexprs - exprs
def get_relevant_facts(proposition, assumptions=(True,), context=global_assumptions, use_known_facts=True, exprs=None, relevant_facts=None): newexprs = set() if not exprs: keys = proposition.atoms(AppliedPredicate) # XXX: We need this since True/False are not Basic keys |= Tuple(*assumptions).atoms(AppliedPredicate) if context: keys |= And(*context).atoms(AppliedPredicate) exprs = {key.args[0] for key in keys} if not relevant_facts: relevant_facts = set([]) if use_known_facts: for expr in exprs: relevant_facts.add(get_known_facts_cnf().rcall(expr)) for expr in exprs: for fact in fact_registry[expr.func]: newfact = fact.rcall(expr) relevant_facts.add(newfact) newexprs |= set([key.args[0] for key in newfact.atoms(AppliedPredicate)]) return relevant_facts, newexprs - exprs
def ask(proposition, assumptions=True, context=global_assumptions): """ Method for inferring properties about objects. **Syntax** * ask(proposition) * ask(proposition, assumptions) where ``proposition`` is any boolean expression Examples ======== >>> from sympy import ask, Q, pi >>> from sympy.abc import x, y >>> ask(Q.rational(pi)) False >>> ask(Q.even(x*y), Q.even(x) & Q.integer(y)) True >>> ask(Q.prime(4*x), Q.integer(x)) False **Remarks** Relations in assumptions are not implemented (yet), so the following will not give a meaningful result. >>> ask(Q.positive(x), Q.is_true(x > 0)) # doctest: +SKIP It is however a work in progress. """ from sympy.assumptions.satask import satask if not isinstance(proposition, (BooleanFunction, AppliedPredicate, bool, BooleanAtom)): raise TypeError("proposition must be a valid logical expression") if not isinstance(assumptions, (BooleanFunction, AppliedPredicate, bool, BooleanAtom)): raise TypeError("assumptions must be a valid logical expression") if isinstance(proposition, AppliedPredicate): key, expr = proposition.func, sympify(proposition.arg) else: key, expr = Q.is_true, sympify(proposition) assumptions = And(assumptions, And(*context)) assumptions = to_cnf(assumptions) local_facts = _extract_facts(assumptions, expr) known_facts_cnf = get_known_facts_cnf() known_facts_dict = get_known_facts_dict() if local_facts and satisfiable(And(local_facts, known_facts_cnf)) is False: raise ValueError("inconsistent assumptions %s" % assumptions) # direct resolution method, no logic res = key(expr)._eval_ask(assumptions) if res is not None: return bool(res) if local_facts is None: return satask(proposition, assumptions=assumptions, context=context) # See if there's a straight-forward conclusion we can make for the inference if local_facts.is_Atom: if key in known_facts_dict[local_facts]: return True if Not(key) in known_facts_dict[local_facts]: return False elif (isinstance(local_facts, And) and all(k in known_facts_dict for k in local_facts.args)): for assum in local_facts.args: if assum.is_Atom: if key in known_facts_dict[assum]: return True if Not(key) in known_facts_dict[assum]: return False elif isinstance(assum, Not) and assum.args[0].is_Atom: if key in known_facts_dict[assum]: return False if Not(key) in known_facts_dict[assum]: return True elif (isinstance(key, Predicate) and isinstance(local_facts, Not) and local_facts.args[0].is_Atom): if local_facts.args[0] in known_facts_dict[key]: return False # Failing all else, we do a full logical inference res = ask_full_inference(key, local_facts, known_facts_cnf) if res is None: return satask(proposition, assumptions=assumptions, context=context) return res
def ask(proposition, assumptions=True, context=global_assumptions): """ Method for inferring properties about objects. **Syntax** * ask(proposition) * ask(proposition, assumptions) where ``proposition`` is any boolean expression Examples ======== >>> from sympy import ask, Q, pi >>> from sympy.abc import x, y >>> ask(Q.rational(pi)) False >>> ask(Q.even(x*y), Q.even(x) & Q.integer(y)) True >>> ask(Q.prime(x*y), Q.integer(x) & Q.integer(y)) False **Remarks** Relations in assumptions are not implemented (yet), so the following will not give a meaningful result. >>> ask(Q.positive(x), Q.is_true(x > 0)) # doctest: +SKIP It is however a work in progress. """ from sympy.assumptions.satask import satask if not isinstance(proposition, (BooleanFunction, AppliedPredicate, bool, BooleanAtom)): raise TypeError("proposition must be a valid logical expression") if not isinstance(assumptions, (BooleanFunction, AppliedPredicate, bool, BooleanAtom)): raise TypeError("assumptions must be a valid logical expression") if isinstance(proposition, AppliedPredicate): key, expr = proposition.func, sympify(proposition.arg) else: key, expr = Q.is_true, sympify(proposition) assumptions = And(assumptions, And(*context)) assumptions = to_cnf(assumptions) local_facts = _extract_facts(assumptions, expr) known_facts_cnf = get_known_facts_cnf() known_facts_dict = get_known_facts_dict() if local_facts and satisfiable(And(local_facts, known_facts_cnf)) is False: raise ValueError("inconsistent assumptions %s" % assumptions) # direct resolution method, no logic res = key(expr)._eval_ask(assumptions) if res is not None: return bool(res) if local_facts is None: return satask(proposition, assumptions=assumptions, context=context) # See if there's a straight-forward conclusion we can make for the inference if local_facts.is_Atom: if key in known_facts_dict[local_facts]: return True if Not(key) in known_facts_dict[local_facts]: return False elif (local_facts.func is And and all(k in known_facts_dict for k in local_facts.args)): for assum in local_facts.args: if assum.is_Atom: if key in known_facts_dict[assum]: return True if Not(key) in known_facts_dict[assum]: return False elif assum.func is Not and assum.args[0].is_Atom: if key in known_facts_dict[assum]: return False if Not(key) in known_facts_dict[assum]: return True elif (isinstance(key, Predicate) and local_facts.func is Not and local_facts.args[0].is_Atom): if local_facts.args[0] in known_facts_dict[key]: return False # Failing all else, we do a full logical inference res = ask_full_inference(key, local_facts, known_facts_cnf) if res is None: return satask(proposition, assumptions=assumptions, context=context) return res