alt Hacker NewsI got lost when OP talked about using 10 integers to choose from 3 choices. I think I figured out what was missing in the explanation.
random_u64() Mod 3 does indeed have a single bucket that is oversized. This overweights one option by about 5×10^-20.
rand() Itself has only 32767 possible values, so it's also common for a bucket to be overweighted depending on the number of buckets.
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omoikane • today at 3:13 AM
> rand() Itself has only 32767 possible values
For MingW maybe (due to MSVCRT). I think most libraries such as glibc have RAND_MAX at 2147483647.
Makes you wonder at what point overweighting by about 5×10^-20 is something you'd want to care about.