mirror of
https://github.com/python/cpython.git
synced 2025-10-26 11:14:33 +00:00
170 lines
6.4 KiB
Python
170 lines
6.4 KiB
Python
import math
|
|
import unittest
|
|
|
|
class PowTest(unittest.TestCase):
|
|
|
|
def powtest(self, type):
|
|
if type != float:
|
|
for i in range(-1000, 1000):
|
|
self.assertEqual(pow(type(i), 0), 1)
|
|
self.assertEqual(pow(type(i), 1), type(i))
|
|
self.assertEqual(pow(type(0), 1), type(0))
|
|
self.assertEqual(pow(type(1), 1), type(1))
|
|
|
|
for i in range(-100, 100):
|
|
self.assertEqual(pow(type(i), 3), i*i*i)
|
|
|
|
pow2 = 1
|
|
for i in range(0, 31):
|
|
self.assertEqual(pow(2, i), pow2)
|
|
if i != 30 : pow2 = pow2*2
|
|
|
|
for i in list(range(-10, 0)) + list(range(1, 10)):
|
|
ii = type(i)
|
|
inv = pow(ii, -1) # inverse of ii
|
|
for jj in range(-10, 0):
|
|
self.assertAlmostEqual(pow(ii, jj), pow(inv, -jj))
|
|
|
|
for othertype in int, float:
|
|
for i in range(1, 100):
|
|
zero = type(0)
|
|
exp = -othertype(i/10.0)
|
|
if exp == 0:
|
|
continue
|
|
self.assertRaises(ZeroDivisionError, pow, zero, exp)
|
|
|
|
il, ih = -20, 20
|
|
jl, jh = -5, 5
|
|
kl, kh = -10, 10
|
|
asseq = self.assertEqual
|
|
if type == float:
|
|
il = 1
|
|
asseq = self.assertAlmostEqual
|
|
elif type == int:
|
|
jl = 0
|
|
elif type == int:
|
|
jl, jh = 0, 15
|
|
for i in range(il, ih+1):
|
|
for j in range(jl, jh+1):
|
|
for k in range(kl, kh+1):
|
|
if k != 0:
|
|
if type == float or j < 0:
|
|
self.assertRaises(TypeError, pow, type(i), j, k)
|
|
continue
|
|
asseq(
|
|
pow(type(i),j,k),
|
|
pow(type(i),j)% type(k)
|
|
)
|
|
|
|
def test_powint(self):
|
|
self.powtest(int)
|
|
|
|
def test_powfloat(self):
|
|
self.powtest(float)
|
|
|
|
def test_other(self):
|
|
# Other tests-- not very systematic
|
|
self.assertEqual(pow(3,3) % 8, pow(3,3,8))
|
|
self.assertEqual(pow(3,3) % -8, pow(3,3,-8))
|
|
self.assertEqual(pow(3,2) % -2, pow(3,2,-2))
|
|
self.assertEqual(pow(-3,3) % 8, pow(-3,3,8))
|
|
self.assertEqual(pow(-3,3) % -8, pow(-3,3,-8))
|
|
self.assertEqual(pow(5,2) % -8, pow(5,2,-8))
|
|
|
|
self.assertEqual(pow(3,3) % 8, pow(3,3,8))
|
|
self.assertEqual(pow(3,3) % -8, pow(3,3,-8))
|
|
self.assertEqual(pow(3,2) % -2, pow(3,2,-2))
|
|
self.assertEqual(pow(-3,3) % 8, pow(-3,3,8))
|
|
self.assertEqual(pow(-3,3) % -8, pow(-3,3,-8))
|
|
self.assertEqual(pow(5,2) % -8, pow(5,2,-8))
|
|
|
|
for i in range(-10, 11):
|
|
for j in range(0, 6):
|
|
for k in range(-7, 11):
|
|
if j >= 0 and k != 0:
|
|
self.assertEqual(
|
|
pow(i,j) % k,
|
|
pow(i,j,k)
|
|
)
|
|
if j >= 0 and k != 0:
|
|
self.assertEqual(
|
|
pow(int(i),j) % k,
|
|
pow(int(i),j,k)
|
|
)
|
|
|
|
def test_big_exp(self):
|
|
import random
|
|
self.assertEqual(pow(2, 50000), 1 << 50000)
|
|
# Randomized modular tests, checking the identities
|
|
# a**(b1 + b2) == a**b1 * a**b2
|
|
# a**(b1 * b2) == (a**b1)**b2
|
|
prime = 1000000000039 # for speed, relatively small prime modulus
|
|
for i in range(10):
|
|
a = random.randrange(1000, 1000000)
|
|
bpower = random.randrange(1000, 50000)
|
|
b = random.randrange(1 << (bpower - 1), 1 << bpower)
|
|
b1 = random.randrange(1, b)
|
|
b2 = b - b1
|
|
got1 = pow(a, b, prime)
|
|
got2 = pow(a, b1, prime) * pow(a, b2, prime) % prime
|
|
if got1 != got2:
|
|
self.fail(f"{a=:x} {b1=:x} {b2=:x} {got1=:x} {got2=:x}")
|
|
got3 = pow(a, b1 * b2, prime)
|
|
got4 = pow(pow(a, b1, prime), b2, prime)
|
|
if got3 != got4:
|
|
self.fail(f"{a=:x} {b1=:x} {b2=:x} {got3=:x} {got4=:x}")
|
|
|
|
def test_bug643260(self):
|
|
class TestRpow:
|
|
def __rpow__(self, other):
|
|
return None
|
|
None ** TestRpow() # Won't fail when __rpow__ invoked. SF bug #643260.
|
|
|
|
def test_bug705231(self):
|
|
# -1.0 raised to an integer should never blow up. It did if the
|
|
# platform pow() was buggy, and Python didn't worm around it.
|
|
eq = self.assertEqual
|
|
a = -1.0
|
|
# The next two tests can still fail if the platform floor()
|
|
# function doesn't treat all large inputs as integers
|
|
# test_math should also fail if that is happening
|
|
eq(pow(a, 1.23e167), 1.0)
|
|
eq(pow(a, -1.23e167), 1.0)
|
|
for b in range(-10, 11):
|
|
eq(pow(a, float(b)), b & 1 and -1.0 or 1.0)
|
|
for n in range(0, 100):
|
|
fiveto = float(5 ** n)
|
|
# For small n, fiveto will be odd. Eventually we run out of
|
|
# mantissa bits, though, and thereafer fiveto will be even.
|
|
expected = fiveto % 2.0 and -1.0 or 1.0
|
|
eq(pow(a, fiveto), expected)
|
|
eq(pow(a, -fiveto), expected)
|
|
eq(expected, 1.0) # else we didn't push fiveto to evenness
|
|
|
|
def test_negative_exponent(self):
|
|
for a in range(-50, 50):
|
|
for m in range(-50, 50):
|
|
with self.subTest(a=a, m=m):
|
|
if m != 0 and math.gcd(a, m) == 1:
|
|
# Exponent -1 should give an inverse, with the
|
|
# same sign as m.
|
|
inv = pow(a, -1, m)
|
|
self.assertEqual(inv, inv % m)
|
|
self.assertEqual((inv * a - 1) % m, 0)
|
|
|
|
# Larger exponents
|
|
self.assertEqual(pow(a, -2, m), pow(inv, 2, m))
|
|
self.assertEqual(pow(a, -3, m), pow(inv, 3, m))
|
|
self.assertEqual(pow(a, -1001, m), pow(inv, 1001, m))
|
|
|
|
else:
|
|
with self.assertRaises(ValueError):
|
|
pow(a, -1, m)
|
|
with self.assertRaises(ValueError):
|
|
pow(a, -2, m)
|
|
with self.assertRaises(ValueError):
|
|
pow(a, -1001, m)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
unittest.main()
|