rational.rb Integer#lcm correction

[erlercw]

From: Bret Jolly ([email protected])

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

 

[erlercw]

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