Python GCD.greatest_common_divisor Examples

Example #1

File: gcd_test.py Project: NicovincX2/Python-3.5

 def test_gcd(self):
     self.assertEqual(fractions.gcd(30, 50),
                      GCD.greatest_common_divisor(30, 50))
     self.assertEqual(fractions.gcd(55555, 123450),
                      GCD.greatest_common_divisor(55555, 123450))
     self.assertEqual(fractions.gcd(-30, -50),
                      GCD.greatest_common_divisor(-30, -50))
     self.assertEqual(fractions.gcd(-1234, 1234),
                      GCD.greatest_common_divisor(-1234, 1234))

Example #2

 def test_gcd(self):
     self.assertEqual(fractions.gcd(30, 50),
                      GCD.greatest_common_divisor(30, 50))
     self.assertEqual(fractions.gcd(55555, 123450),
                      GCD.greatest_common_divisor(55555, 123450))
     self.assertEqual(fractions.gcd(-30, -50),
                      GCD.greatest_common_divisor(-30, -50))
     self.assertEqual(fractions.gcd(-1234, 1234),
                      GCD.greatest_common_divisor(-1234, 1234))

Example #3

File: modular_multiplicative_inverse.py Project: zxz53000/Algorithms-1

def modular_multiplicative_inv(a, m):
    if m == 1:
        return 0
    if m < 1:
        raise ValueError('Modulus should be ve+ int > 0')
    # check for co-prime condition
    if gcd.greatest_common_divisor(a, m) != 1:
        raise ValueError('a and m are not co-primes')

    # Make var "a" positive if it's negative
    if a < 0:
        a %= m

    # Initialise vars
    m0 = m
    x0 = 0
    x1 = 1

    while a > 1:
        # Calculate quotient q; store m into temp t
        q = a / m
        t = m

        # Calculate m as remainder(a, m); store temp t into a
        m = a % m
        a = t

        # Assign x0 into temp t; Calculate x0 and store temp t into x1
        t = x0
        x0 = x1 - q * x0
        x1 = t

    # If x1 is negative then add modulus m0
    if x1 < 0:
        x1 += m0

    return x1

Example #4

File: modular_multiplicative_inverse.py Project: charulagrl/Algorithms

def modular_multiplicative_inv(a, m):
	if m == 1:
		return 0
	if m < 1:
		raise ValueError('Modulus should be ve+ int > 0')
	# check for co-prime condition
	if gcd.greatest_common_divisor(a, m) != 1:
		raise ValueError('a and m are not co-primes')

	# Make var "a" positive if it's negative
	if a < 0:
		a %= m

	# Initialise vars
	m0 = m
	x0 = 0
	x1 = 1

	while a > 1:
		# Calculate quotient q; store m into temp t
		q = a / m
		t = m

		# Calculate m as remainder(a, m); store temp t into a
		m = a % m
		a = t

		# Assign x0 into temp t; Calculate x0 and store temp t into x1
		t = x0
		x0 = x1 - q * x0
		x1 = t

	# If x1 is negative then add modulus m0
	if x1 < 0:
		x1 += m0

	return x1