Comment #8 on issue 2043 by smichr: log should not expand(1/x) (was "expand log can be more complete" and "logcombine can be less strict")
http://code.google.com/p/sympy/issues/detail?id=2043
ahh...I see. On the other hand log((x-y)*(x+y)) would still split because the x+y is positive. But maybe there would be some case where there would be two terms with subtractions, so I get the general idea. But I still would like to see a better way to handle this. I don't know much about how the new assumptions would work, but along the posify lines one could implement the logic, "replace all args of log functions with positive dummies" so the log((x-y)*(x+y)) would be replaced with log(p1*p2) along with wherever else they occurred in the expression. I think I like the kwarg to log the best, however. Just like there are optimized isqrt and sqrt in languages, perhaps a CAS needs an "rlog" via that hint.
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