On Sun, May 22, 2011 at 12:35 PM, Ondrej Certik <ond...@certik.cz> wrote: > On Sun, May 22, 2011 at 8:34 AM, Andy Ray Terrel <andy.ter...@gmail.com> > wrote: >> On Sat, May 21, 2011 at 10:51 PM, Ondrej Certik <ond...@certik.cz> wrote: >>> On Sat, May 21, 2011 at 8:21 PM, Andy Ray Terrel <andy.ter...@gmail.com> >>> wrote: >>>> On Sat, May 21, 2011 at 10:10 PM, Ronan Lamy <ronan.l...@gmail.com> wrote: >>>>> Le samedi 21 mai 2011 à 21:50 -0500, Andy Ray Terrel a écrit : >>>>>> On Sun, May 15, 2011 at 6:54 PM, Brian Granger <elliso...@gmail.com> >>>>>> wrote: >>>>>> > On Sat, May 14, 2011 at 1:49 PM, Vinzent Steinberg >>>>>> > <vinzent.steinb...@googlemail.com> wrote: >>>>>> >> On 14 Mai, 18:31, Ronan Lamy <ronan.l...@gmail.com> wrote: >>>>>> >>> _op_priority was designed to help with implementing arithmetic >>>>>> >>> operations, particularly for things that aren't "calculus >>>>>> >>> expressions" >>>>>> >>> yet have meaningful __add__, __mul__, __pow__, etc. such as vectors >>>>>> >>> and >>>>>> >>> operators of various kinds. But it turns out that it doesn't really >>>>>> >>> help >>>>>> >>> (http://groups.google.com/group/sympy/browse_thread/thread/810e127bc41...) >>>>>> >>> and it isn't used anywhere currently. >>>>>> >>> >>>>>> >>> It also has fundamental flaws that prevent it from ever evolving >>>>>> >>> into a >>>>>> >>> complete solution to the problem: it assumes that the priority order >>>>>> >>> is >>>>>> >>> the same for all operations and turns this order into a total order, >>>>>> >>> introducing couplings between objects that would otherwise have no >>>>>> >>> knowledge of each other. >>>>>> >>> >>>>>> >>> So, I think that there's little benefit in including into 0.7.0, but >>>>>> >>> it >>>>>> >>> would have the significant drawback of committing us to support this >>>>>> >>> feature for who knows how long, and therefore of making much more >>>>>> >>> difficult to refactor this critical mechanism. And if _op_priority >>>>>> >>> does >>>>>> >>> turn out to be useful, it can easily be added back in after the >>>>>> >>> release >>>>>> >>> by reverting the removal. >>>>>> >> >>>>>> >> If it is not used, I think we can remove it. >>>>>> > >>>>>> > +1 >>>>>> > >>>>>> >>>>>> Please don't do this. I use op_priority all the time. Its the one >>>>>> reason I haven't release my code because I depend on this >>>>>> functionality. >>>>> >>>>> You're a bit late: it's been removed already, in >>>>> 041995d37563f1e0743c75a311035b553f66741e. But we could revert that >>>>> commit. Can you open an issue and link to code that uses _op_priority? >>>>> >>>> >>>> Hmm the last three weeks have been a blur for me. >>>> >>>> My whole tensor library [0] depends on it, and I thought it was a great >>>> idea even if it seems incomplete because core code will just call Mul, >>>> Add, ... never giving the custom call a callback. >>>> >>>> issue opened at [1] >>> >>> Does anyone know a better solution to fix this problem? >>> >>> If not, then I am +1 to push it back in, and improve upon it later. >>> >>> Andy -- is sympy missing some tests, that your library depends on? If >>> so, we should add it into sympy, so that we make sure things don't get >>> broken. Once somebody implements a better solution, we'll simply >>> provide an upgrade path. >> >> test_priority from that commit was what I was using. But roughly I >> need multiple dispatch so I can override the dispatch of the algebraic >> operators. If SymPy doesn't want to support this I can move to the >> pymoblics system. > > How does pymbolic handle this issue?
Andreas told me Pymbolic works on a graph and you register visitor classes. Unfortunately reading his code [0] doesn't actually handle this. =( Maybe that is why he was so easily convinced to move to SymPy. [0] http://git.tiker.net/pymbolic.git/blob/HEAD:/pymbolic/primitives.py > > 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. > > -- 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.
