[ruby-core:107563] [Ruby master Feature#18463] Random number generation with xoshiro

Issue #18463 has been updated by bbrklm (Benson Muite).


Work in progress gem for xoshiro128++ [0]

Python continues to use Mersenne twister as default[1], but Numpy has been recently extended to include other options[2].

Some considerations for C++ are discussed in [3]. 

Randen [4] calls hardware implemented functions, but these may not be available on all architectures.

If there is need for backwards compatibility, Mersenne twister can be kept as default, for example the Go community has chosen to keep an unusual random number generator as default[5][6][7][8]. My expectation is that xoshiro128++ is a reasonable general purpose replacement for Mersenne twister for core language. Java also chains together random sequences of bytes to generate random big integers[9], so this is probably ok for portability of the base language, though tests and other quality assurances would be nice as well.  More specialized random number generators might be better in a separate gem. 

One further issue might be using the random number generator with Ractors. Some of the random number generators provide a jump function to ensure that random sequences generated at in parallel do not overlap for a large fixed set of invocations. This is not in the interfaces available in `include/ruby/random.h`. GPU libraries also often make several independent streams of random numbers.

[0] https://gitlab.com/bkmgit/xoshiro128plusplus
[1] https://docs.python.org/3/library/random.html
[2] https://github.com/bashtage/randomgen/
[3] http://open-std.org/JTC1/SC22/WG21/docs/papers/2019/p1932r0.pdf
[4] https://github.com/google/randen
[5] https://cs.opensource.google/go/go/+/963753d3f95a79d2826de2837e6296f7b8117dc6
[6] https://github.com/golang/go/blob/master/src/math/rand/rng.go
[7] https://github.com/golang/go/issues/26263
[8] https://github.com/golang/go/issues/21835
[9] https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/java/math/BigInteger.java#L713
[10] https://github.com/clMathLibraries/clRNG
[11] https://github.com/ROCmSoftwarePlatform/rocRAND

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Feature #18463: Random number generation with xoshiro
https://bugs.ruby-lang.org/issues/18463#change-96477

* Author: bbrklm (Benson Muite)
* Status: Open
* Priority: Normal
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Xoshiro https://prng.di.unimi.it/  random number generation is typically faster than Mersenne Twister currently used in Ruby in https://github.com/ruby/ruby/blob/master/random.c  It would be good to allow use of xoshiro either as an option or as default. Xoshiro is the default for Fortran https://gcc.gnu.org/onlinedocs/gfortran/RANDOM_005fNUMBER.html and Julia https://github.com/JuliaLang/julia/tree/master/stdlib/Random/src Happy to implement this.



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