FWIW, I think vinzent's approach (local assumptions automatically injected into the context of the symbol creation) is the best way to go.
On 1 Mai, 07:47, Ondrej Certik <ond...@certik.cz> wrote: > On Sat, Apr 30, 2011 at 10:36 AM, Haz <christian.mu...@gmail.com> wrote: > > So a few things to respond to... > > Tom: > >>Can you describe what went wrong with these branches? In particular, > >>why can the following naive strategy not work: > > >>1. Make the new system at least as good as the old one. That is > >>whenever I can write foo.is_bar I can write ask(foo, Q.bar) and I will > >>get at least as good an answer. In particular Symbol('x', > >>positive=True) should register automatically in the global assumptions > >>that x > 0 (if I understand correctly how the new system works...). > >>2. Replace all queries foo.is_bar by ask(foo, Q.bar). > >>3. Remove all implementations of the is_bar properties. > >>4. Remove all remaining remnants of the old system. > > This is what was largely tried with a branch last summer: > > - https://github.com/haz/sympy/tree/disconnect-assumptions-2 > > There was push-back from the community since removing the Symbol('x', > > positive=True) syntax was largely frowned upon. > > I am still very much convinced, that this disconnect-assumptions-2 is > the simplest and easiest way to get rid of the old assumptions, so > that we can start speeding up the core, and start using some other > system for them. > > I would be interested in the community vote on this idea. I vote +1. I > am aware that Ronan voted -1 last year. What do others think? > > 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.