On Wednesday, April 2, 2014 9:56:29 PM UTC+2, Matthew wrote: > > Right, but ideally A(i, -i, j) and A(j, -i, i) *wouldn't unify. *Actually > in this sort of case I suppose that they would because it could be that i > == j. >
Mmm, you're right. I didn't consider this problem. I believe that some precautions should be taken when using the unification, in order to avoid nonsense expressions, i.e. unification results should first be verified. I didn't test this on rewriterule, but there could be an uncaught exception. > Generally speaking though unification variables do need match consistently > within a term. (a, a) does not match to (1, 2). Perhaps we could consider > all tensor indices on one side to be wild? > > Well, maybe it's better to continue this discussion as soon as there will be some code attempt to apply rewriterule on tensors. There are still some issues to solve, after that I would like to try to implement a partial derivative operator on tensors with rewriterule. -- 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/d85930c9-755e-4985-9edc-4d7c5919c8fb%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
