def _norm(self):
"Normalize: remove the common denominator"
if self.num == 0:
self.den = 1
return
if self.den == 0:
#invalud value
if self.num < 0:
self.num = -1
elif self.num > 0:
self.num = 1
return
if self.den<0: #normalize sign
self.num = -self.num
self.den = -self.den
k = numtheor.gcd(self.num, self.den)
self.num /= k
self.den /= k
def simplify(a,b):
d = gcd(a,b)
return (a/d, b/d)
