Rational.rb Integer#lcm correction

ruby-talk
1

From: Bret Jolly (oinkoink+unet@rexx.com)
Subject: Broken lcm
2004-05-20 11:05:01 PST
Ruby version: ruby 1.9.0 (2004-05-10) [i686-linux]
The lcm method used by mathn (and defined in rational.rb)
is broken.

...

irb(main):003:0> 0.lcm(0)
ZeroDivisionError: divided by 0

...

But the lcm of 0 and 0 is well-defined (and equal to 0).

Regards, Bret

The following corrects Integer#lcm in rational.rb (with one less call to #abs, too).

  def lcm(other)
    if self.zero? or other.zero?
      0
    else
      (self.div(self.gcd(other)) * other).abs
    end
  end

2

Sorry, I forgot Integer#gcdlcm.

def lcm(other)
   if self.zero? or other.zero?
     0
   else
     (self.div(self.gcd(other)) * other).abs
   end
end

  def gcdlcm(other)
    gcd = self.gcd(other)
    if self.zero? or other.zero?
      [gcd, 0]
    else
      [gcd, (self.div(gcd) * other).abs]
    end
  end