Re: [Boost-users] [Random] normal distribution different behaviour 1.55 vs 1.57

Subject: Re: [Boost-users] [Random] normal distribution different behaviour 1.55 vs 1.57
From: John Maddock (boost.regex_at_[hidden])
Date: 2014-12-18 12:51:22

>> Neither for 1.56.0 nor 1.57.0 does the change-log list an update to the
>> random numbers library, so first I am puzzled why the libraries behave
>> differently (though [Math] has undergone some changes -> propagation to
>> [Random]?). Second, it is not clear to me why for the first bunch of
>> uniformly distributed variates the results are identical, while for the
>> second, after normally distributed variates were generated, the are not.
>> It appears that the generation of normally distributed variates changes
>> the whole state of the random numbers engine in a different manner [e.g
>> multiple engine calls ??].
>> Any insight into what is going on here is much appreciated. And
>> foremost: Is any of 1.55 or 1.57 bugged, that is one should be clearly
>> preferred over the other?
>
> I've observed this, too! The change seems to have been introduced in Boost version 1.56.

Looks like the normal distribution was completely rewritten between 
those two releases: 
https://github.com/boostorg/random/commit/f0ec97ba36c05ef00f2d29dcf66094e3f4abdcde

Beyond that I know nothing, John.