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galoisfield.py
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galoisfield.py
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import gcd
class GF:
def __init__(self, p):
self.elem.p = p
def __str__(self):
return "GF(%s)" % str(self.elem.p)
class elem:
def __init__(self, v):
self.v = v.v if isinstance(v, GF.elem) else v % self.p
def __eq__(self, a):
assert isinstance(a, GF.elem)
return self.v == a.v
def __ne__(self, a):
assert isinstance(a, GF.elem)
return self.v == a.v
def __add__(self, a):
assert isinstance(a, GF.elem)
return GF.elem(self.v + a.v)
def __neg__(self):
return GF.elem(-self.v)
def __sub__(self, a):
assert isinstance(a, GF.elem)
return GF.elem(self.v - a.v)
def __mul__(self, a):
assert isinstance(a, GF.elem)
return GF.elem(self.v * a.v)
def __invert__(self):
x, _ = gcd.extEuclid(self.v, self.p)
return GF.elem(x)
def __div__(self, a):
assert isinstance(a, GF.elem)
return self * ~a
def __pow__(self, a):
return GF.elem(pow(self.v, a, self.p))
def __str__(self):
return str(self.v)
def __repr__(self):
return repr(self.v)
def main():
GF5 = GF(5)
print GF5
print GF5.elem(3) + GF5.elem(2)
print GF5.elem(3) - GF5.elem(2)
print GF5.elem(3) * GF5.elem(2)
print ~GF5.elem(2)
print GF5.elem(3) / GF5.elem(2)
print GF5.elem(3) ** 3
if __name__ == '__main__':
main()