The Mersenne Twister is an exceptionally high-quality, fast random number
generator. This package contains two versions of it in Java, written by Sean
Luke. MersenneTwister is a complete drop-in subclass replacement for
java.util.Random. MersenneTwisterFast is algorithmically identical, except
that it isn't synchronized, and it's not a subclass of Random. This, plus
other speed improvements, makes it over twice the speed.