sympy/sympy — pull request #1064 by smichr (2012-02-16 20:33:45+00:00)
Title: watch out for off-by-one calc of magnitude

The previous expression was hanging so the log calculation was
re-written with a call to mpf_log.

The off-by-one error is to miscompute the magnitude so something
like round(S(1)) becomes 1.e+0 rather than 1.