def sample_messy_power(variable, entropy):
"""Returns unsimplified power expression like ((x**2)**3/x**4)**2/x**3."""
if entropy <= 0:
return variable
which = random.choice([1, 2, 3])
if which == 1:
exponent_entropy = min(2, entropy)
entropy -= exponent_entropy
exponent = number.integer_or_rational(exponent_entropy, signed=True)
left = sample_messy_power(variable, entropy)
return ops.Pow(left, exponent)
entropy_left = entropy / 2
if entropy_left < 1:
entropy_left = 0
entropy_right = entropy - entropy_left
if random.choice([False, True]):
entropy_left, entropy_right = entropy_right, entropy_left
left = sample_messy_power(variable, entropy_left)
right = sample_messy_power(variable, entropy_right)
if which == 2:
return ops.Mul(left, right)
else:
return ops.Div(left, right)
def testDescendants(self):
constants = [ops.Constant(i) for i in range(6)]
# (1 + 2*3**4) / 5 - 6
expression = ops.Sub(
ops.Div(
ops.Add(
constants[0],
ops.Mul(
constants[1],
ops.Pow(
constants[2],
constants[3]))),
constants[4]),
constants[5])
descendants = expression.descendants()
descendants = ops._flatten(descendants)
for constant in constants:
self.assertIn(constant, descendants)
self.assertEqual(descendants.count(constant), 1)
# Also test top-level.
self.assertEqual(constants[0].descendants(), [constants[0]])
# Also general structure.
constant = ops.Constant(3)
expression = ops.Neg(constant)
self.assertEqual(set(expression.descendants()), set([constant, expression]))
def div_by_sqrt_k():
"""Do sqrt(k * base) / sqrt(k)."""
entropy_k = min(1, entropy)
k = number.integer(entropy_k, signed=False, min_abs=2)
entropy_left, entropy_right = _surd_split_entropy_two(entropy - entropy_k)
k_base_expr = _sample_surd(k * base, entropy_left, max_power, True)
while True:
k_expr = _sample_surd(k, entropy_right, max_power, True)
if k_expr.sympy() != 0:
break
return ops.Div(k_base_expr, k_expr)
def testDiv(self):
div = ops.Div(2, 3)
self.assertEqual(str(div), '2/3')
self.assertEqual(div.sympy(), sympy.Rational(2, 3))
div = ops.Div(2, sympy.Rational(4, 5))
self.assertEqual(str(div), '2/(4/5)')
self.assertEqual(div.sympy(), sympy.Rational(5, 2))
div = ops.Div(1, ops.Div(2, 3))
self.assertEqual(str(div), '1/(2/3)')
self.assertEqual(div.sympy(), sympy.Rational(3, 2))
div = ops.Div(ops.Div(2, 3), 4)
self.assertEqual(str(div), '(2/3)/4')
self.assertEqual(div.sympy(), sympy.Rational(1, 6))
div = ops.Div(2, ops.Mul(3, 4))
self.assertEqual(str(div), '2/(3*4)')
div = ops.Div(2, sympy.Function('f')(sympy.Symbol('x')))
self.assertEqual(str(div), '2/f(x)')