The Xorshift family of random number generators were introduced by George Marsaglia in 2003 in a paper published in the Journal of Statistical Software:
- Marsaglia, G. (2003) Xorshift RNGs. Journal of Statistical Software vol. 8 issue 14. http://www.jstatsoft.org/v08/i14/
This repository contains a working copy of the reference code provided by Marsiglia in his paper, tweaked very slightly as follows:
-
Marsaglia's paper uses
unsigned longas the word type, which may be either 32- or 64-bit depending on the implementation. This has been changed to uint32_t to ensure the word type is an unsigned 32-bit integer. -
Some small typos in Marsaglia's paper have been corrected. Without these corrections the Xorshift32 and Xorshift160 implementations depart strongly from uniformity. See the git history log for details of these corrections.
In all other respects the xorNNN() functions here reflect Marsaglia's sample code and may thus be useful to verify other implementations.
DISCLAIMER: no claims are made for the suitability of these RNGs for any purpose, certainly not crypto or any mission-critical or security-related applications. Even using them to verify other Xorshift implementations may be dubious, given the observed typos in the original source material. The author thinks he has corrected everything that needs to be corrected, but you should check for yourself. In other words, use this code at your own risk. :-)