I was reading this section and the last paragraph stated that the example code was not thread-safe. My question is: wouldn’t that help increase its randomness (i.e. if multiple threads were to concurrently execute those lines)?
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I was reading this section and the last paragraph stated that the example code was not thread-safe. My question is: wouldn’t that help increase its randomness (i.e. if multiple threads were to concurrently execute those lines)?
PRNGs are carefully engineered (well, maybe not RANDU) to yield predictable and sufficiently randomly distributed results. They don’t have to be truly random, they just have to satisfy statistical quality tests, yield a large-enough period and be deterministic with the same seed.
If you happen to use the generator from multiple threads simultaneously all those guarantees go down the drain. Most importantly you cannot have a reproducible result (which is extremely important in simulations). Then the state might change or perhaps you get the same number twice in different threads, those things.
You definitely don’t want to go there. Create one PRNG per thread (preferrably with seeds that are linearly independent).