@All: This is a cry for help. I am completely stumped at the *express* method. The implementation that I had before had a flaw that I hadn't noticed until now (until Gilbert's PR on by branch). Anyway, let me try to describe the situation.
Initially, I had an separate method that would take a vector and return it separated by coordinate systems in dictionary form. To my chagrin, this kind of separation cannot always work. Consider two coordinate systems, c0 and c1, both rectangular. Let us have a vector, v. v = c0.x * c1.e_y express Obviously, this cannot be separated into vectors separated by coordinate systems. This is the case I wasn't considering when I wrote the express method last. And that's why, I need to rewrite a new express method. I have been thinking of how to implement this but I'm getting nowhere. I do have one way, that I think might work and am currently writing the code for it. But, I'm not at all too sure of it. I think that by now, all three of you have a fair idea of the code. Please suggest an algorithm to accomplish 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 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. For more options, visit https://groups.google.com/groups/opt_out.
