Hi, On 13 October 2011 11:15, smichr <smi...@gmail.com> wrote:
> Does anyone have a suggestion of how to best retrieve the Integer gcd > and factors from an Add instead of getting the Rational? > > >>> terms_gcd(3*x+9*x**2/2) # I want 3*x*(3*x/2 + 1) > 3*x*(3*x + 2)/2 > >>> primitive(3*(3*x/2 + 1)) > (3/2, 3*x + 2) > >>> gcd(3*x,9*x**2/2) > x > The tool you should use is primitive() (or content(), but this is purely polynomial manipulation function). You have to change definition of rational GCD: In [1]: def qgcd(self, a, b): ...: try: ...: ring = self.get_ring() ...: except DomainError: ...: return self.one ...: else: ...: g = ring.gcd(self.numer(a), self.numer(b)) ...: return self.convert(g, ring) ...: In [2]: import types In [3]: QQ.gcd = types.MethodType(qgcd, QQ, type(QQ)) In [4]: primitive(3*x/2 + 6) Out[4]: ⎛ x ⎞ ⎜3, ─ + 2⎟ ⎝ 2 ⎠ For the case of QQ, qgcd() could be simplified, but I made this function generic, because I could be implemented in Field as an alternate GCD algorithm. I was thinking about changing GCD algorithm easier, e.g. primitive(3*x/2 + 6, QQ__gcd=qgcd) or even primitive(3*x/2 + 6, QQ__gcd="integer"). > > -- > 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. > > Mateusz -- 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.
