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235 :: Random number generator

• MFlamer (orginal) [2013-09-11T16:14:07+02:00] view original

  I needed a source of random ints. I tried the system.random proc but it was generating duplicates which was causing me problems. So I threw together this Mersenne Twister object. I didn't do much testing on it, but it does seem to work correctly. It generates a nice supply of random ints. It's hosted at https://bitbucket.org/mflamer/nimutils if anyone wants to use it. The original algorithm is here http://en.wikipedia.org/wiki/Mersenne_twister

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• gradha (orginal) [2013-09-11T22:05:44+02:00] view original

  Can you elaborate on the problem you had with system.random? If there is a problem with it it may be a good idea to fix it.

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• Jehan (orginal) [2013-09-11T22:45:52+02:00] view original

  The underlying C function rand() can be assumed to be of poor quality; on glibc systems, in particular, it's basically a linear congruential generator. Its benefit is portability.

  All of rand(), random() and the rand48 family of RNGs suffer from the additional problem that they perform poorly in a multi-threaded system, because they need an exclusive lock (or comparably expensive operations) to protect their internal state, creating a serialization bottleneck.

  If you are doing work that needs a quality source of random numbers, you generally want an implementation where you know and can control its properties.

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