On Fri, Jan 31, 2014 at 06:35:45AM -0800, Aaron Meurer wrote:
>    You're duplicating work, though.

The problem is:
1) we want calculate_series to be deterministic (don't depend on simplify heuristics)
2) we want detect zero-equivalence as best as we can

simplify() is best suited for the second task, but not for the first.

Any better ideas?