def checkMathPredicates(name, atom):
args = get_args(atom)
if is_variable(args[0]) or is_variable(args[1]):
return False
a = get_value(args[0])
b = get_value(args[1])
if name == 'isBigger':
return a >= b
elif name == 'equal':
return a == b
elif name == 'sum':
if is_constant(args[2]) and (a + b == get_value(args[2])):
return True
elif is_variable(args[2]):
args[2] = substitute(args[2],
{get_name(args[2]): make_const(a + b)})
return True
elif name == 'dif':
if is_constant(args[2]) and (a - b == get_value(args[2])):
return True
elif is_variable(args[2]):
args[2] = substitute(args[2],
{get_name(args[2]): make_const(a - b)})
return True
return False
def checkMathPredicates(name, atom, subst = None): args = get_args(atom) if is_variable(args[0]) or is_variable(args[1]): return False a = get_value(args[0]) b = get_value(args[1]) if name == 'isBigger': return a >= b elif name == 'isSmaller': return a < b elif name == 'equal': return a == b elif name == 'sum': if is_constant(args[2]) and (a + b == get_value(args[2])): return True elif is_variable(args[2]): subst[get_name(args[2])] = make_const(a + b) return True elif name == 'dif': if is_constant(args[2]) and (a - b == get_value(args[2])): return True elif is_variable(args[2]): subst[get_name(args[2])] = make_const(a - b) return True return False
def equal_terms(t1, t2):
if is_constant(t1) and is_constant(t2):
return get_value(t1) == get_value(t2)
if is_variable(t1) and is_variable(t2):
return get_name(t1) == get_name(t2)
if is_function_call(t1) and is_function(t2):
if get_head(t1) != get_head(t2):
return all([equal_terms(get_args(t1)[i], get_args(t2)[i]) for i in range(len(get_args(t1)))])
return False
def forward_chaining(kb, theorem, verbose=True):
# Salvăm baza de date originală, lucrăm cu o copie
local_kb = deepcopy(kb)
# Două variabile care descriu starea căutării
got_new_facts = True # s-au găsit fapte noi la ultima căutare
is_proved = False # a fost demostrată teorema
# Verificăm dacă teorema este deja demonstrată
for fact in filter(is_fact, local_kb):
if unify(fact, theorem):
if verbose:
print("This already in KB: " + print_formula(fact, True))
is_proved = True
break
while (not is_proved) and got_new_facts:
got_new_facts = False
for rule in filter(is_rule, local_kb):
# Pentru fiecare regulă
new_facts = apply_rule(rule, list(filter(is_fact, local_kb)))
new_facts = list(
filter(
lambda fact: not any(
list(
filter(lambda orig: is_equal_to(fact, orig),
local_kb))), new_facts))
if new_facts:
if verbose:
print("Applied rule: " + print_formula(rule, True) +
", obtained " + str(len(new_facts)) + " new facts.")
if any(filter(lambda t: is_variable(t), get_args(get_conclusion(rule)))) and \
any(filter(lambda fact: is_equal_to(fact, get_conclusion(rule)), new_facts)):
print(
"Demonstration is too general, the conclusion is not instantiated (facts obtained:",
",".join([print_formula(f, True)
for f in new_facts]), ").")
return False
got_new_facts = True
for fact in new_facts:
#if verbose: print("New fact: " + print_formula(fact, True))
if unify(fact, theorem) != False:
is_proved = True
add_statement(local_kb, fact)
if verbose:
print("Now in KB: " + print_formula(fact, True))
break
add_statement(local_kb, fact)
if is_proved:
break
if verbose:
if is_proved:
print("The theorem is TRUE!")
else:
print("The theorem is FALSE!")
return is_proved