Abstract¶ I optimized built-in library Rational. It is more than 3.7 times faster now in some cases. Background¶ Rational is increasing its importance year by year. Ruby 1.9.2 uses Rational as internal representation of Time. Ruby 2.1 introduced Rational literal ("r" suffix). But it's performance is not good enough because its implementation uses Ruby-level method calling with rb_funcall(), in spi