Related blog post : https://radfordneal.wordpress.com/2015/05/21/exact-computati...

As someone who has worked with building, testing, and numerical software, this seems like a great thing. Generally floating point computations are effectively non-deterministic: you (or the compiler) change something that doesn't seem like it matters and all of a sudden your result changes. Having more methods available that give you the deterministically best right thing at little additional expense is great!