On Sep 14, 2008, at 4:53 PM, William Stein wrote: > On Sun, Sep 14, 2008 at 1:25 PM, Justin Walker <[EMAIL PROTECTED]> wrote: [snip] >> [2] I fussed over this while working on my patch, and finally decided >> to leave it alone. Is there any cause to be concerned about >> caching, >> by code using the BQF code? It might be disconcerting to find >> things >> changing under you. I may have missed discussion on the lists >> about >> this; apologies if this has been kneaded to a tough consistency. >> > > Make damn sure that the __hash__ method is *not* implemented > if quadratic forms are mutable. Otherwise, bad things will happen. > Otherwise, it's just a design choice. E.g., mutable matrices are > certainly useful, but mutable polynomials usually aren't so we > don't (officially) have them (though there is an _underscore method > to mutate even a polynomial). > > I personally would tend to vote to have a method "reduced" that > returns the reduced version of the quadratic form. I usually prefer > for elements to be immutable whenever possible...
We don't have a __hash__() method for forms at this point, but thanks for bringing that up. I'd have overlooked that, for sure. Is mutability/immutability assumed when needed, or is there a way of testing the underlying types? I prefer immutability as well, but John seems to feel that it's A Good Thing to have reduce() 'mute' the form :-}. I'll defer to him, in this case, since the code is already accepted. Justin -- Justin C. Walker, Curmudgeon-at-Large () The ASCII Ribbon Campaign /\ Help Cure HTML Email --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
