> Stefan, can you give a brief explanation of your experience? In particular > what difficulties did you run into?
The current tensor canonicalization and representation for tensors does not adhere to most of sympy's class invariants. - eq is occasionally about mathematical equality, not structural one, and it is even raising errors in some cases, which break dictionary lookups and so on - you can not recreate objects using func and args - substitution does not work (nothing related to tree traversal works actually) - many others in the same style In one sentence: the implemented algorithms are very smart, but they completely disregard the invariants that sympy uses to work with the symbolic trees. I tried to go step by step and reinstate these invariants, but my knowledge of the module was insufficient. (actually, going in the other direction might be easier: the module when I was looking at it was not using any of sympy's methods, so it was not really necessary to subclass Basic or Expr). In any case Franz is more aware of these issues than me and he was working on fixing some of them (I was not following the work so I do not know how much of this is still relevant). > > > On Fri, Mar 28, 2014 at 6:17 PM, Stefan Krastanov > <[email protected]> wrote: >> >> > I came to the conclusion that the best solution to implement Quantum >> > Field >> > Theory in SymPy is to use the unify module combined with the new tensor >> > module. >> >> I can not agree more with statement. I would be the happiest person on >> Earth if you/the community succeeds at such a refactoring. I actually >> tried to do it on one or two occasions (it actually happened exactly >> when you joined us), but such a task is beyond me and regrettably I >> will not have free time in the near future to help. >> >> Sorry for this rather nonconstructive post, I just wanted to say that >> I am happy that somebody is thinking about this. >> >> -- >> 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 [email protected]. >> To post to this group, send email to [email protected]. >> 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/CAD8szLyr1qqFoKwUcOOCrcfs%2B%3DeretJ8g1bNAnb5CTJ0HrcY-w%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 [email protected]. > To post to this group, send email to [email protected]. > 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-EoyBb3XcdCSsEeqBV-9su%2B7sMB8etZZmfwmsdeGm3XPg%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 [email protected]. To post to this group, send email to [email protected]. 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/CAD8szLw1M6E-OLrhsqqW0_RsocXywtF8Ost2%3D3kD7Vp4-3O_Kw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
