from fractions import Fraction from sys import maxint from modp import * class PAdic: def __init__(self, p): self.p = p self.val = '' # current known value self.prec = 0 # current known precision self.order = 0 # order/valuation of number pass # initialize object as subclass perhaps def get(self, prec): 'Return value of number with given precision.' if self.value == 0: return '0' # * prec while self.prec < prec: # update val based on value self.val = self._nextdigit() + self.val self.prec += 1 return self.val # TODO add decimal point or trailing zeros def _nextdigit(self): 'Calculate next digit of p-adic number.' raise NotImplementedError def getdigit(self, index): 'Return digit at given index.' return int(self.get(index+1)[0]) # return value with precision up to 32 bits def __int__(self): return int(self.get(32), p) def __str__(self): return self.get(32) def __repr__(self): pass # arithmetic operations def __add__(self, other): return PAdicAdd(self.p, self, other) def __radd__(self, other): return PAdicAdd(self.p, other, self) def __sub__(self, other): return PAdicAdd(self.p, self, PAdicNeg(self.p, other)) def __rsub__(self, other): return PAdicAdd(self.p, other, PAdicNeg(self.p, self)) def __smul__(self, other): return PAdicMul(self.p, self, other) def __rsub__(self, other): return PAdicMul(self.p, other, self) # p-adic norm def __abs__(self): if self.order == maxint: return 0 norm = Fraction(1) if self.order > 0: norm.numerator = self.p ** self.order if self.order < 0: norm.denominator = self.p ** self.order return norm class PAdicConst(PAdic): def __init__(self, p, value): PAdic.__init__(self, p) value = Fraction(value) # calculate valuation if value == 0: self.value = value self.val = '0' return self.norm = Fraction(1) self.order = 0 while not value.numerator % self.p: self.norm /= self.p self.order += 1 value.numerator /= self.p while not value.denominator % self.p: self.norm *= self.p valuation -= 1 value.denominator /= self.p self.value = value def _nextdigit(self): 'Calculate next digit of p-adic number.' rem = ModP(self.p, self.value.numerator) / ModP(self.p, self.value.denominator) self.value -= rem self.value /= self.p return rem class PAdicAdd(PAdic): 'Sum of two p-adic numbers.' def __init__(self, p, arg1, arg2): PAdic.__init__(self, p) self.carry = 0 self.arg1 = arg1 self.arg2 = arg2 def _nextdigit(self): s = self.arg1.getdigit(self.prec) + self.arg2.getdigit(self.prec) + self.carry self.carry = s // self.p return s % self.p class PAdicNeg(PAdic): 'Negation of a p-adic number.' def __init__(self, p, arg): PAdic.__init__(self, p) self.arg = arg def _nextdigit(self): if self.prec == 0: return self.p - self.arg.getdigit(0) return self.p - 1 - self.arg.getdigit(0) class PAdicMul(PAdic): 'Product of two p-adic numbers.' def __init__(self, p, arg1, arg2): PAdic.__init__(self, p) self.carry = 0 self.arg1 = arg1 self.arg2 = arg2 def _nextdigit(self): s = sum(self.arg1.getdigit(i) * self.arg2.getdigit(self.prec - i) for i in xrange(self.prec + 1)) + self.carry self.carry = s // self.p return s % self.p