@hackage pcgen2.0.0

A fast pseudorandom number generator, as presented by M.E. O'Neill on http://www.pcg-random.org, See that site for information on the particulars of the technique used. This particular implementation uses two Word64 of internal data and produces a Word32 of output per step. On 64-bit machines it's two to three times as fast as StdGen and uses the same amount of space.