Comment #3 on issue 2044 by asmeurer: log(exp(x)) != x unless x is real http://code.google.com/p/sympy/issues/detail?id=2044
Well, the last time I made a change that broke something in the limits (prevention of automatic combination of exp(x)*exp(y) => exp(x + y)), I had to write a custom simplification function that did the old behavior and inject it into the limits code where it required it (in that case, it was splitting the base and exponent combination in powsimp() so you could do powsimip(expr, deep=True, combine='exp')).
Maybe we should have a general case simplification function that applies f(f^(-1)(x)) => x (f^(-1) is f inverse) for the cases where it doesn't equal x in the general case (e.g., sqrt(x**2), asin(sin(x)), log(exp(x)), etc.). It would have to be assumptions violating, but it would be much easier to call that than to try to fiddle around with the actual assumptions.
-- You received this message because you are subscribed to the Google Groups "sympy-issues" group. To post to this group, send email to sympy-iss...@googlegroups.com. To unsubscribe from this group, send email to sympy-issues+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy-issues?hl=en.
