Hi, I implemented the extended_euclid() in Diophantine module without knowing that gcdex() existed. However, Chris pointed out that extended_euclid() is much faster. Take a look at here<https://github.com/sympy/sympy/pull/2168#discussion-diff-4672557>. He suggested to rename extended_euclid() to igcdex().
I also feel that when we are dealing with integers, i.e when using igcd()we should allow inputting more than two numbers at a time. It doesn't break the API, does it? Regards, Thilina On Thu, Jul 11, 2013 at 2:12 PM, Mateusz Paprocki <matt...@gmail.com> wrote: > Hi, > > On 11 July 2013 10:17, Stephen Loo <hingk...@gmail.com> wrote: > >> Hi all, >> >> I found that there are many different kind of gcd in sympy different >> module, such as >> >> sympy.core.numbers.igcd >> sympy.polys.polytools.gcd >> sympy.polys.polytools.gcdex >> sympy.polys.polytools.gcd_list >> sympy.polys.polytools.half_gcdex >> >> And the new one >> sympy.solvers.diophantine.extended_euclid >> >> They calculate integer gcd or polynomial gcd. I suggest to make single >> public function call, like gamma, put in integer argument and return >> integer, put in polynomial argument and return polynomial. And gcd function >> should not limit to 2 integer only, for example, gcd(10, 15, 20) = 5 >> >> Any idea? Any suggestion? >> > > First of all, functions gcdex() and half_gcdex() don't count because they > implement extended Euclidean algorithm. I didn't know about > extended_euclid(). It seems redundant. igcd() is a specialized function > that works only with integers and is needed internally to reduce overhead > that gcd() function has. The function you would like to have is gcd(). It > works with numbers, polynomials and whatever that has a gcd() method. It > either takes two arguments (plus symbols and options in polynomial case) or > one iterable (plus symbols and options in polynomial case). The iterable > case is equivalent to calling gcd_list() explicitly (that's why there is > gcd_list()). Currently it isn't possible to support gcd(1, 2, 3, 4, 5) > syntax, because that effectively means (in the current API) compute GCD of > 1 and 2 which are polynomials in 3, 4, 5 (treated as symbols) in the > default coefficient domain (which is integer ring). In the integer case > this limitation could be relaxed easily, but then the API would be > inconsistent, because gcd(x, y, z) would still mean GCD of polynomials x > and y in z (x*z**0, y*z**0) (over ZZ[x, y]). > > >> Thanks. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sympy+unsubscr...@googlegroups.com. >> To post to this group, send email to sympy@googlegroups.com. >> Visit this group at http://groups.google.com/group/sympy. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > Mateusz > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sympy+unsubscr...@googlegroups.com. > To post to this group, send email to sympy@googlegroups.com. > Visit this group at http://groups.google.com/group/sympy. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. For more options, visit https://groups.google.com/groups/opt_out.
