On Mon, Mar 26, 2018 at 10:01 AM, albertmcchan
<albertmcchan@yahoo.com> wrote:
If what you are saying is true, period of last128() is also 2^128 - 1, all unique.
Each last128() map 1-to-1 to 2^128 - 1 internal states.
one last128() pattern will never occurs. (all zeroes ?)
The period of the RNG cannot be more than 2^128, because the state is only 128 bits. The state is updated using a function that maps the zero state to the zero state, and any non-zero state to a non-zero state, so the maximal possible period is 2^128-1, assuming you don't seed it with all-zero bits (which the Lua seed algorithm avoids).
This type of RNG is explained here: