[PATCH] Fix Bug 83237 - Values returned by std::poisson_distribution are not distributed correctly

[Jonathan Wakely]

On 12/12/17 21:37 +0100, Paolo Carlini wrote:
>Hi,
>
>On 12/12/2017 19:42, Michele Pezzutti wrote:
>>Hi.
>>
>>Yes, I looked at the text before submitting the patch.
>>
>>I contacted Devroye and he confirmed that another reader had also 
>>pointed out this bug but not the solution. I sent him my proposed 
>>patch, he will look into it (no idea when though).
>Nice.
>>I would state that "comparison function for x = 1 is e^(1/78)" 
>>(which becomes 1/78 as the algorithm uses log-probabilities).
>>
>>I think the change is needed because otherwise, for that particular 
>>bin, the rejection probability is lower than it should be, resulting 
>>in a higher number of samples.
>Ok. Ideally I would be much less nervous about committing the patch if 
>we either 1- Had Luc's explicit green light; 2- Were able to 
>*rigorously deduce* within the framework of the book why the change is 
>needed. That said, the patch makes sense to me and so far holds up 
>well in all my tests (I'm currently running a full make check). I 
>would say, let's wait a week or so and then make the final decision. 
>Jon, do you agree? Ideas about further testing? (eg, some code you are 
>aware of stressing Poisson?)

No, I have nothing useful to add here, but I CC'd Ed on the PR as I'd
like his input.