sympy/sympy — pull request #956 by smichr (2012-01-11 02:11:44+00:00)
Title: 2978: float and int exponents combine in Mul.flatten

Since as_coeff_mul only pulls out Rational coefficients, it was
not appearing that x**2.0 and x**-1 could combine. By using as_coeff_Mul
instead, the exponents on the common base now combine.

see issue 2978: http://code.google.com/p/sympy/issues/detail?id=2978