That is true that if you can replace indexes with a multiple argument function. But an index is an integer not a real. Furthermore the feature that makes indexed quantity behave just like a numpy array is neat.
I think that when you manipulate a tensor/matrix field it would be nice be be able to do algebra. I also noticed that you cannot differentiate with respect to an indexed value: *************************************************** f = IndexedBase('f') i = Idx('i') diff(f[i]**2,f[i]) >> Can't differentiate wrt the variable: f[i], 1 **************************************************** So, I understand that the idea is pleasant. Someone willing to extend indexes ? Otherwise, how can I help ? Do you have pointers to the ways indexes are working ? Thanks Guillaume -- 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/1d0de17c-0a7e-4c9b-a779-3a82d62a6c61%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.