method

prime_division

v1_9_2_180 - Show latest stable - 0 notes - Class: Prime

prime_division(value, generator= Prime::Generator23.new) public

Returns the factorization of value.

Parameters

`value`	An arbitrary integer.
`generator`	Optional. A pseudo-prime generator.

+generator+.succ must return the next
pseudo-prime number in the ascendent
order. It must generate all prime numbers,
but may generate non prime numbers.

Exceptions

ZeroDivisionError

when value is zero.

Example

For an arbitrary integer n = p_1**e_1 * p_2**e_2 * .… * p_n**e_n, prime_division(n) returns [[p_1, e_1], [p_2, e_2], .…, [p_n, e_n]].

Prime.prime_division(12) #=> [[2,2], [3,1]]

Show source

# File lib/prime.rb, line 195
  def prime_division(value, generator= Prime::Generator23.new)
    raise ZeroDivisionError if value == 0
    if value < 0
      value = -value
      pv = [[-1, 1]]
    else
      pv = []
    end
    for prime in generator
      count = 0
      while (value1, mod = value.divmod(prime)
             mod) == 0
        value = value1
        count += 1
      end
      if count != 0
        pv.push [prime, count]
      end
      break if value1 <= prime
    end
    if value > 1
      pv.push [value, 1]
    end
    return pv
  end

prime_division

Related methods

Parameters

Exceptions

Example