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Refactor power method to handle negative exponents #159

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Refactor power method to handle negative exponents #159

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21 changes: 13 additions & 8 deletions py_ecc/fields/field_elements.py
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Original file line number Diff line number Diff line change
Expand Up @@ -290,14 +290,19 @@ def __truediv__(self: T_FQP, other: int | T_FQ | T_FQP) -> T_FQP:
return self.__div__(other)

def __pow__(self: T_FQP, other: int) -> T_FQP:
o = type(self)([1] + [0] * (self.degree - 1))
t = self
while other > 0:
if other & 1:
o = o * t
other >>= 1
t = t * t
return o
if other < 0:
return self.inv() ** (-other)
res = type(self)([1] + [0] * (self.degree - 1))
base = self
exp = other

while exp > 0:
if exp % 2 == 1:
res = res * base
base = base * base
exp //= 2

return res

# Extended euclidean algorithm used to find the modular inverse
def inv(self: T_FQP) -> T_FQP:
Expand Down