def test_minus_1(self):
"""walk_minus should not create nested Plus nodes"""
x = Symbol("x", INT)
y = Symbol("y", INT)
oldx = Symbol("oldx", INT)
m_1 = Int(-1)
i_2 = Int(2)
i_4 = Int(4)
src = Times(i_2, oldx)
src = Plus(src, x)
src = Minus(src, Times(i_4, y))
src = Times(m_1, src)
td = TimesDistributor()
res = td.walk(src)
self.assertValid(Equals(src, res))
# root is Plus.
self.assertTrue(res.is_plus(),
"Expeted summation, got: {}".format(res))
# no other Plus in children: only Times of symbs and constants.
stack = list(res.args())
while stack:
curr = stack.pop()
if curr.is_times():
stack.extend(curr.args())
else:
self.assertTrue(curr.is_symbol() or curr.is_constant(),
"Expected leaf, got: {}".format(res))
def test_minus_0(self):
x = Symbol("x", INT)
y = Symbol("y", INT)
i_0 = Int(0)
src = Plus(x, y)
src = Minus(x, src)
src = LT(src, i_0)
td = TimesDistributor()
res = td.walk(src)
self.assertValid(Iff(src, res))
def test_times_distributivity_smtlib_nra(self):
from pysmt.test.smtlib.parser_utils import formulas_from_smtlib_test_set
test_set = formulas_from_smtlib_test_set(logics=[QF_LRA, QF_NRA])
for (_, fname, f, _) in test_set:
td = TimesDistributor()
_ = td.walk(f)
for (old, new) in td.memoization.items():
if not old.is_times(): continue
if old is new: continue # Nothing changed
self.assertValid(Equals(old, new), (old, new),
solver_name="z3")
def test_times_distributivity_smtlib_nra(self):
from pysmt.test.smtlib.parser_utils import formulas_from_smtlib_test_set
test_set = formulas_from_smtlib_test_set(logics=[QF_LRA, QF_NRA])
for (_, fname, f, _) in test_set:
td = TimesDistributor()
_ = td.walk(f)
for (old, new) in td.memoization.items():
if not old.is_times(): continue
if old is new: continue # Nothing changed
self.assertValid(Equals(old, new),
(old, new), solver_name="z3")
def test_times_distributivity(self):
r = Symbol("r", REAL)
s = Symbol("s", REAL)
td = TimesDistributor()
f = Times(Plus(r, Real(1)), Real(3))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Plus(r, Real(1)), s)
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Plus(r, Real(1), s), Real(3))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Minus(r, Real(1)), Real(3))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Minus(r, Real(1)), s)
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Minus(Real(1), s), Real(3))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Minus(r, Real(1)), Plus(r, s))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
# (r + 1) * (s-1) = r*s + (-r) + s - 1
f = Times(Plus(r, Real(1)), Minus(s, Real(1)))
fp = td.walk(f).simplify()
target = Plus(Times(r, s), Times(r, Real(-1)), s, Real(-1))
self.assertValid(Equals(fp, target), fp)
self.assertTrue(fp.is_plus(), fp)
def test_times_distributivity(self):
r = Symbol("r", REAL)
s = Symbol("s", REAL)
td = TimesDistributor()
f = Times(Plus(r, Real(1)), Real(3))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Plus(r, Real(1)), s)
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Plus(r, Real(1), s), Real(3))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Minus(r, Real(1)), Real(3))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Minus(r, Real(1)), s)
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Minus(Real(1), s), Real(3))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
f = Times(Minus(r, Real(1)), Plus(r, s))
fp = td.walk(f)
self.assertValid(Equals(f, fp), (f, fp))
# (r + 1) * (s-1) = r*s + (-r) + s - 1
f = Times(Plus(r, Real(1)), Minus(s, Real(1)))
fp = td.walk(f).simplify()
target = Plus(Times(r, s),
Times(r, Real(-1)),
s,
Real(-1))
self.assertValid(Equals(fp, target), fp)
self.assertTrue(fp.is_plus(), fp)