sympy/sympy — pull request #1200 by catchmrbharath (2012-04-03 17:44:48+00:00)
Title: Fix for Issue 2120: Floating point arguments converted to Rational.

A few algorithms like is_collinear check whether the slopes are equal or not, which fails for floating points due to floating point precision errors. One way to counter this is to add an additional tolerance argument.
I have implemented a basic work-through where I convert every floating point argument to Rational.