In mathematics, a Weyl sequence is a sequence from the equidistribution theorem proven by Hermann Weyl:[1]
The sequence of all multiples of an irrational α,
0, α, 2α, 3α, 4α, ...
is equidistributed modulo 1.[2]
In other words, the sequence of the fractional parts of each term will be uniformly distributed in the interval [0, 1). == In computing == In [[computing]], an integer version of this sequence is often used to generate a discrete uniform distribution rather than a continuous one. Instead of using an irrational number, which cannot be calculated on a digital computer, the ratio of two integers is used in its place. An integer k is chosen, relatively prime to an integer modulus m. In the common case that m is a power of 2, this amounts to requiring that k is odd.
The sequence of all multiples of such an integer k,
0, k, 2k, 3k, 4k, …
is equidistributed modulo m.
That is, the sequence of the remainders of each term when divided by m will be uniformly distributed in the interval [0, ''m''{{nowrap end}}). The term appears to originate with [[George Marsaglia]]’s paper "Xorshift RNGs".[3] The following C code generates what Marsaglia calls a "Weyl sequence":
d += 362437;In this case, the odd integer is 362437, and the results are computed modulo because d is a 32-bit quantity. The results are equidistributed modulo 232.