Hello, I have opened an issue for the input of lambdify. If you want to disallow sets as inputs I think it is fair. However, It would be nice to have that free_symbol can be given directly as input for lambdify, is that possible? should I use something else than free_symbols for this purpose?
On Thu, Jul 9, 2020 at 9:55 PM Aaron Meurer <asmeu...@gmail.com> wrote: > Can you open an issue in the issue tracker for this? I agree that sets > should not be allowed. > > Aaron Meurer > > On Thu, Jul 9, 2020 at 3:08 AM Roberto <franceschini.robe...@gmail.com> > wrote: > > > > I have seen that lambdify wants a list for the arguments to be treated > as symbols. This list can be also give as a python set, e.g. {x,y,z }, > which is exactly what would be returned by a .free_symbol property. If > lambdify is feed a set like that of the output of .free_symbol it may > change their order in the conversion from set to list. This is done > silently and may cause major disfunction in the use of the lamdified > function because you think x is x, but is y instead and so on. > > I would like to ask developers to check for the type of the lambdify > list of arguments and throw a warning to flag that a set is being converted > and that the ordering is not guaranteed. > > Given that .free_symbols returns a set, not a list, this is very common > pitfall in my opinion and must be prevented. > > > > -- > > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/c1517b79-490b-4a1b-b526-3e3842b55fbco%40googlegroups.com > . > > -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/CAKgW%3D6KuqnjJHTObyDxK0tvaF_Frxzd-MfyQSY94v-oTUWyNAg%40mail.gmail.com > . > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAJxM9JqSoqQQkYH9UUXGyXNqRtY9VHJxKByc8Fv8%2BPaqFudP6w%40mail.gmail.com.