Comment #19 on issue 1694 by nicolas.pourcelot: solve has many issues with fractions http://code.google.com/p/sympy/issues/detail?id=1694
Thanks Chris for your comments, even if I disagree with some ;) 1) I think checksolution() should clearly indicate when it can not conclude, either by returning None (like .is_real, .is_positive, or is_zero do), or by returning NotImplemented. Returning False or True when it can't conclude is imo not option, and I can't assume that checksolution() will become good enough to conclude in any case ;) 2) Indeed. Substitution, expanding, and then simplifying. Or, better then, I'll have a look at simplify, to simplify step by step. 3) No, -1 is *not* a solution of this equation, since x/(1+x) is not defined for x = -1. It is however a solution of the equation after simplification, but it's not the same. I suspect you're a physicist ;) (Nor should 0 be a solution of x^2/x=0, but sympy simplifies x^2/x in x without assuming x != 0) 4) Well, I thought about it, but I must admit I didn't want to spend too much time on this patch (I just wanted to patch a few things I needed for my own work). Ok, I'll try to do it. 5) Ok, done. 6) I didn't inspect existing test, I expect them to be all right. >>> complex((x**Rational(1,2)+x**Rational(1,3)+x**Rational(1,4)).subs(x, >>> -9.5 - 2.8*I)) (3.0367413036900337-6.0250802087551731j) Yes, you're right, 0 seems to be the only solution. However, I think this is unrelated to this issue, so it may be solved as you sayed in another patch (unless, of course, we choose to check every solution of solve(), in every strategy and every case)... but I don't think it's the right thing to do). -- You received this message because you are listed in the owner or CC fields of this issue, or because you starred this issue. You may adjust your issue notification preferences at: http://code.google.com/hosting/settings --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy-issues" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sympy-issues?hl=en -~----------~----~----~----~------~----~------~--~---
