Mir Random [WIP]

Joseph Rushton Wakeling via Digitalmars-d digitalmars-d at puremagic.com
Wed Nov 23 02:47:58 PST 2016


On Wednesday, 23 November 2016 at 01:34:23 UTC, Andrei 
Alexandrescu wrote:
> I'm unclear on what that statistically unsafe default behavior 
> is - my understanding is it has to do with RNGs being 
> inadvertently copied. It would be great to formalize that in a 
> well-explained issue.

I'll see if I can write that up in depth some time soon.  TBH 
though I think the problem is less about RNGs and more about 
stuff like RandomSample and RandomCover (and, in future, random 
distributions that have internal state, like a struct 
implementing a normal distribution using the Ziggurat algorithm 
internally).

It's not so difficult to stop RNG state being copied 
inadvertently, but when you have ranges wrapping ranges wrapping 
ranges, each containing their own extra state that cannot be 
copied by value, things get a bit more complicated.


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