On Thu, Apr 23, 2009 at 9:48 AM, Ondrej Certik <ond...@certik.cz> wrote: > On Tue, Apr 21, 2009 at 8:46 AM, dhruv <lasnabvu...@gmail.com> wrote: >> It seems like the above is the only thing I can do! The Poly class >> can be instantiated using a few different calling schemes (lists, >> tuples, dictionaries, &c.) and I'm going to have to anticipate each >> scheme and extract the parameters I want from it, all in >> GeneratingFunction.__new__. > > It depends what functionality you want to support --- if you want your > class to work with all those schemes *and* you need to do something > with the arguments, then I think it's the only way. However, we can > refactor Poly, so that these kind of things are easy to do.
Btw, the reason to use __new__ instead of __init__ is that in __init__ you cannot decide which instance to return (e.g. the instance has already been created). For simplifications like x+x we need to return Mul(2, x). This is decided in the __new__ method, so that no unnecessary instances are created. Ondrej --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
