On 05/19/2015 07:48 AM, Joachim Durchholz wrote: > > An external dictionary isn't ideal but better than this, at least from > the maintainer's perspective. > >>> Maybe we can give you better help if you describe your use case in some >>> more detail. >> >> At some point I create symbols from which I know, that they are >> derivatives and I want to store their order. Using the classes Function >> and Derivative is no real option because I want the symbols to behave as >> symbols on most occasions. > > Ah. This sounds like a design problem in Derivative to me that we should > fix. > Can you post what you did, what you'd have needed to get out, and what > SymPy gave you?
I think strongest argument for me was that the string representation of the expressions gets too long for Functions and Derivatives. This reduces my chance to "see" any structure. Second argument is that I have a (own) library for modeling differential forms which internally uses Symbol and does not straight forwardly work with Function instances. E.g. x.name -> 'x' x(t).name -> AttributeError However, this discussions make me think, if using Functions would not be the better alternative > >> In general, I think there are situations, where it might be useful to >> store some algorithm-specific extra information to some symbols. > > For algorithms of SymPy itself, I think the algorithms should be fixed :-) > > It would be useful for coding external algorithms, but it does come with > ramifications (most importantly the potential for namespace conflicts); > from a maintenance perpective, it's far better if such an algorithm does > its own data management. OK. I can perfectly live with 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/555B0556.2040908%40gmx.de. For more options, visit https://groups.google.com/d/optout.
