On Sun, May 19, 2013 at 9:43 PM, Julien Rioux <julien.ri...@gmail.com> wrote: > On Sunday, 19 May 2013 23:13:44 UTC-4, Aaron Meurer wrote: >> >> On Sun, May 19, 2013 at 7:27 PM, Chris Smith <smi...@gmail.com> wrote: >> >> - I thought we decided to remove NotImplementedError from solve(). Or >> >> was that just None? >> >> >> > >> > I don't recall >> >> Well I think we should do it. It should be an easy fix. Just catch >> NotImplementedError in solve() and return [], and fix all the tests, >> and also change the code base to not catch it any more. >> >> > > Please don't return [] (empty list) instead of NotImplementedError, you > would have [] mean either there is no solution, or we don't know if there is > any solution, and that would just be a step backward as far as issue 3699 is > concerned. To remove the NotImplementedError we first need a bigger object > with some sort of attribute to indicate if it's a complete solution set or > not.
It's not a step backward, because the current system does *not* make that guarantee. If you've been writing code on that assumption, it is wrong. And the plan is to use an object of that sort. NotImplementedError is not a useful way to signal that we didn't find all the solutions because sometimes we can find some but not all solutions (e.g., trivially, multiply the whole expression by x, then 0 will be a solution). Actually, that's a bug in the current system. If you do multiply an equation that gives NotImplementedError by x, you still don't get any solutions. Try solve(cos(x)*x - x**2, x). Aaron Meurer > > Cheers, > Julien > > -- > 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?hl=en-US. > 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?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
