Alexander, All, How is it going with your tensor implementation? I put together some code to implement variance of tensors and uploaded it to github in my tensor_contractions branch [0]. If you would like to build on that, feel free to do so. If you have already made your own implementation, please just choose whatever works best for your framework.
Here is how it works in the advertised branch: >>> A = IndexedBase('A') >>> i = VarIdx('i') >>> A[i.up, i.down] A[^i, _i] >>> get_indices(A[i.up, i.down]) (set(), {}) >>> get_indices(A[i.up, j.down]*x[j.up]) (set([^i]), {}) Cheers, Øyvind [0]: https://github.com/jegerjensen/sympy/tree/tensor_contractions -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.