Example #1
0
def divisor_sum_using_prime_factors(n):
    pf = list(set(prime_factor.prime_factors(n)))
    s = 1
    for p in pf:
        k = 0
        while n % p == 0:
            k += 1
            n //= p
        s *= (p**(k + 1) - 1) // (p - 1)
    return s
Example #2
0
def factorise(n):
    if n < 1:
        return None

    factors = [1]

    pfactors = [x for x in prime_factors(n)]
    pfactors = [x for x in chain.from_iterable(combinations(pfactors, r) for r in range(len(pfactors) + 1))]

    for comb in pfactors:
        product = 1
        for x in comb:
            product *= x
        if product not in factors:
            factors.append(product)

    return sorted(factors)
Example #3
0
def totient(num):
    """
    Counts the numbers that are relative prime to the number.
    This means that if a number 'x' has common divisors with another number 'a' lower than itself,
    it is, 'a' is not relative prime to 'x'.
    This means that if a number is prime, its totient function is its value - 1, as 
    all numbers lower than the number itself is relative prime to the number.
    An example: totient(9):
                1, 2, 4, 5, 7, 8 are all relative prime
                3, 6, and 9 have at least one common divisor with 9
                returns 6, as there are 6 numbers relative prime to 9
        
    If you visit 'https://en.wikipedia.org/wiki/Euler%27s_totient_function'
    this function uses the function described under euler's product formula.
    """
    # set(prime_factors(num)) to get only unique primes.
    # it is the (1 - 1/p) part from the wiki-page
    uniqe_primes = [(1 - 1 / p) for p in set(prime_factors(num))]
    phi = num * product(
        uniqe_primes)  # The totient function is commonly called phi
    phi = int(round(phi))  # As phi is a whole number
    return phi
Example #4
0
def phi(n):  #Eulers phi-funktion
    #Giver p-1 for alle primfaktorerne
    return produkt([p - 1 for p in prime_factors(n)])  #Og ganger dem så sammen
 def test_prime(self):
   self.assertEqual(prime_factors(5), [5,])
 def test_known(self):
   self.assertEqual(prime_factors(13195), [5, 7, 13, 29,])
 def test_nonprime_noncomposite(self):
   self.assertFalse(prime_factors(1))
 def test_composite(self):
   self.assertEqual(prime_factors(6), [2, 3,])