from Hacker News

A while back I built a science library supporting both physical and abstract dimensions. Almost immediately I discovered working with floating point numbers suck in that space and BigDecimal isn't much better in terms of managing scale wrt margin of error across calculations, Java doesn't make this easy.

Rationals are in my view much better suited for science/math in that information cannot be unintentionally lost when using them. So I made a Rational for Java, and in the process _forced_ Java to work better with science and math.