Hi On Fri, Sep 23, 2011 at 9:13 PM, Aaron Meurer <asmeu...@gmail.com> wrote:
> If you just want to do simple arithmetic, you can use the FF class: > > In [1]: FF(12) > Out[1]: ℤ₁₂ > > In [2]: FF(12)(4) > Out[2]: 4 mod 12 > > In [3]: FF(12)(4)/FF(12)(11) > Out[3]: 8 mod 12 > > Note that the name FF comes from finite field, so this may not work if > the modulus is not a power of a prime. For example: > > In [4]: FF(12)(4)/FF(12)(2) > --------------------------------------------------------------------------- > NotInvertible Traceback (most recent call last) > > /Users/aaronmeurer/Documents/python/sympy/sympy/<ipython console> in > <module>() > > > /Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/domains/modularinteger.pyc > in __div__(self, other) > 92 > 93 if val is not None: > ---> 94 return self.__class__(self.val * self._invert(val)) > 95 else: > 96 return NotImplemented > > > /Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/domains/modularinteger.pyc > in _invert(cls, value) > 160 @classmethod > 161 def _invert(cls, value): > --> 162 return cls.dom.invert(value, cls.mod) > 163 > 164 def invert(self): > > > /Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/domains/ring.pyc > in invert(self, a, b) > 39 return s % b > 40 else: > ---> 41 raise NotInvertible("zero divisor") > 42 > 43 def revert(self, a): > > NotInvertible: zero divisor > > I'm not sure if you will get other errors if you use non-fields. > > When I started writing gf_csolve ( Please see the pull request ) I was aiming to add a function which solve f(x) congruent 0 mod ( n) where f(x) is polynomial and n is any number so I believe that should suffice for the 1st problem. > If you want to solve congruence relations, like x = 2 mod 3, then you > might look at this branch: https://github.com/sympy/sympy/pull/390. > It would be great if you could give that branch a complete review, as > I've only been able to comment on the code quality up to this point. > > Aaron Meurer > > On Fri, Sep 23, 2011 at 2:16 AM, smichr <smi...@gmail.com> wrote: > > I'm not sure where to look in sympy for support of things like solving > > congruence relationships (what number is 2 mod 3, 3 mod 5 and 2 mod 7; > > answer 23 mod 105) and operations modulo n, e.g., from > http://tinyurl.com/3atamuj, > > the following question: > > > > In Z_12, divide 4 by 2, 3, 5, 7,8, and 11 > > > > Do we have support for such things? > > > > -- > > You received this message because you are subscribed to the Google Groups > "sympy" group. > > To post to this group, send email to sympy@googlegroups.com. > > To unsubscribe from this group, send email to > sympy+unsubscr...@googlegroups.com. > > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > > > > > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to sympy@googlegroups.com. > To unsubscribe from this group, send email to > sympy+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > > -- -Regards Hector Whenever you think you can or you can't, in either way you are right. -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.