Re: [Boost-users] [random]: several issues

Subject: Re: [Boost-users] [random]: several issues
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2009-09-22 10:33:11

AMDG

Thomas Mang wrote:
> After some time I came back to the boost random library, and several 
> things I noticed earlier have not changed since years ago. I hereby 
> ask what the present state of ideas regarding these ideas is.
>
> Here's my list:
>
> a) The library itself provides files for random deviates of 
> distributions not given in the documentation (e.g. poisson, gamma) 
> etc. I find it truly sad that implementation and documentation is that 
> out of synchronisation
>
> b) Several distributions require the engine to return a uniform 
> deviate between [0,1), while other's don't have this prerequisite. I 
> find this extremely error prone and purely documented (it is 
> documented, but it should be so clearer, and especially, louder). 
> Worse, I find it even harder (or impossible) to find out which range 
> the engines return. I am not sure if there is any engine returning 
> this range per se, or if I have always to go through uniform_01.
> Worst of all, there is neither a compile time check nor a runtime 
> check if that [0,1) result-requirement of the engine holds (as far as 
> I have seen the code) - I absolutely fail to see why such a critical 
> assert is completely missing, also given the poor state of the 
> documentation.
> The poisson and gamma for example also fall in this category, but are 
> not documented at all. I consider this highly dangerous.

You're not supposed to use the distributions directly.
boost::variate_generator works with any engine and
any distribution.

> c) Random numbers are tightly linked to statistical distributions, 
> offered by the library of it's own. Wouldn't it be convenient to try 
> to integrate the whole distribution part of the random numbers more 
> closely into that library? Presently they are too confusingly standalone.

Are you referring to the distributions in Boost.Math?

> d) Is there anyone actually responsible for the random library at the 
> moment? Is it still under active development / maintained, or is old 
> code simply propagating from release to release ? [No offense 
> intended, but above issues let me have doubts regarding active 
> management).

In Christ,
Steven Watanabe