def test():
snCnf=sncnf()
sol=[];
sol.append(to_cnf(snCnf[1] & ~snCnf[3]))
sol.append(to_cnf(~snCnf[2] & snCnf[3]))
lCnf=[]
for i in range(0,len(snCnf)):
lCnf.append( cnfstr2list( snCnf[i] ) )
lCnfSol=[]
for i in range(0,len(sol)):
lCnf.append( cnfstr2list( sol[i] ) )
def sncnf():
sn = sndef()
n = len(sn) - 1 # number of levels
cnformula = []
formula = []
for output in xrange(0,4):
formula.append( snF(sn, n, output ) )
cnformula.append( to_cnf( formula[output] ) )
#print output, '-->', cnformula[output]
return formula
def res(formula):
formula = rewrite_implication(formula)
formula = logic.to_cnf(logic.expr(formula))
clauses = logic.conjuncts(formula)
print "CNF: " + cnf(formula)
m = 1
for c in clauses:
if logic.tt_true(c):
clauses.remove(c)
else:
a = remove_double_bracket(cnf(c))
print str(m) + ": " + a
m += 1
new = set()
while True:
n = len(clauses)
pairs = [(clauses[i], clauses[j]) for i in range(n)
for j in range(i + 1, n)]
for (ci, cj) in pairs:
resolvents = logic.pl_resolve(ci, cj)
if (len(resolvents) != 0):
if (resolvents[0] not in new):
if (resolvents[0] is logic.FALSE):
print str(m) + ": {}"
else:
print str(m) + ": " + remove_double_bracket(
cnf(resolvents[0])) + " --- (" + str(
clauses.index(ci) +
1) + ", " + str(clauses.index(cj) + 1) + ")"
m += 1
if logic.FALSE in resolvents:
return True
new.update(set(resolvents))
if new.issubset(clauses):
return False
for c in new:
if c not in clauses:
clauses.append(c)
def cnf(formula):
result = "{"
formula = str(formula)
formula = rewrite_implication(formula)
formula = logic.to_cnf(logic.expr(formula))
clauses = logic.conjuncts(formula)
clauses = set(clauses)
clauses = list(clauses)
for c in clauses:
if logic.tt_true(c):
clauses.remove(c)
for c in clauses:
if logic.tt_true(c) is False:
result = result + "{"
lits = logic.disjuncts(c)
lits = set(lits)
lits = list(lits)
for s in lits:
if lits.index(s) == len(lits) - 1:
result = result + str(s) + "}"
else:
result = result + str(s) + ", "
if clauses.index(c) != len(clauses) - 1:
result = result + ","
result = result + "}"
return result
