With respect to wyrand, it seems that all prime numbers are not created equal. I implemented wyrand() using the two primes just below 2^64. The upper 53 bits of each 64-bit random deviate was used to generate a uniform [0,1) floating point deviate. The expected value of the sum of the uniform floating point deviates is 0.5 * #deviates. When using the two primes numbers above, the resulting value was 0.6430236 * #deviates - indicating significant bias in the random deviates generated by wyhash for those particular prime numbers.