Oh, that's even better. Then we don't have to touch the core, and we can merge even experimental things faster.
Aaron Meurer On Fri, Apr 11, 2014 at 10:40 AM, Matthew Rocklin <mrock...@gmail.com> wrote: > Sets is a good play module for this purpose. Union and Intersection > simplify pairwise much like Add and Mul would. I like the pairwise methods > we have but the strategy to orchestrate them could use some cleaning up. > Might be a good place to build intuition. > > See https://github.com/sympy/sympy/pull/2979 > > > On Fri, Apr 11, 2014 at 8:27 AM, Aaron Meurer <asmeu...@gmail.com> wrote: >> >> This has always been the original motivation for multiple dispatch, at >> least in my mind. You can't make objects that do their own thing in >> Add or Mul or whatever. There are a dozen example of this throughout >> SymPy, and a dozen more in user code. There are many hacky ways around >> it, but none are satisfactory. >> >> The problem is, how do you dispatch Add(*args). Any argument of the >> Add might want to do anything with any other argument. You don't want >> to require that arguments be next to each other, because then >> something as simple as Add(yourobject, 0, yourobject) wouldn't do the >> right thing. You can do the n**2 passes, but does it remain efficient >> at that point? >> >> I think we should just start to play with this, especially now that we >> have a decent implementation of multiple dispatch. I'd personally >> rather play with this with a module that I can understand (so, e.g., >> matrix expressions rather than tensores), but anything is better than >> nothing. >> >> Aaron Meurer >> >> On Fri, Apr 11, 2014 at 5:17 AM, F. B. <franz.bona...@gmail.com> wrote: >> > >> > >> > On Friday, April 11, 2014 1:29:11 AM UTC+2, Aaron Meurer wrote: >> >> >> >> There are probably little ways around these things, but nothing clean >> >> without dispatching in the core. >> > >> > >> > Another point in favor of multiple dispatching. >> > >> > By the way, tensor expressions should just become ordinary expression >> > with >> > the addition of an index management mechanism, as well as other features >> > such as components data association. >> > >> > Of course some precautions should be taken, for example all indices have >> > to >> > be contracted if you take the exponential of a tensor expression (I am >> > wondering, did anyone ever define a unique and consistent way to >> > generalize >> > the matrix exponential to tensors of any rank?). >> > >> > -- >> > 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 post to this group, send email to sympy@googlegroups.com. >> > Visit this group at http://groups.google.com/group/sympy. >> > To view this discussion on the web visit >> > >> > https://groups.google.com/d/msgid/sympy/b7592a77-00ef-4c82-a94b-f0e904581c63%40googlegroups.com. >> > >> > For more options, visit https://groups.google.com/d/optout. >> >> -- >> 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 post to this group, send email to sympy@googlegroups.com. >> Visit this group at http://groups.google.com/group/sympy. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/CAKgW%3D6L%2B0wx_h1YFT83swB90WwYq_fL3W6q-61frXxr-rUo0YQ%40mail.gmail.com. >> >> For more options, visit https://groups.google.com/d/optout. > > > -- > 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 post to this group, send email to sympy@googlegroups.com. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/CAJ8oX-Fh-a3sJ9NFRG%3DNt1bxcbkqcTLzcOPTMjGU4Hy%2BxEmdAg%40mail.gmail.com. > > For more options, visit https://groups.google.com/d/optout. -- 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 post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6%2BOOW5iHNsOCbFW26A6zh7j%3DnCm57pNTu8hTCv8m81i5Q%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
