[fpc-devel] Random thread-safe

[thaddy at thaddy.com]

Then wouldn't it be possible to make PRNG's  plugable. The Mersenne 
twister is still good as it is but definitely not suitable for every and 
any case. Marsialigla's might be a better choice nowadays.
And the seeding can nowadays often been done from reading hardware 
random, like on the Raspberry Pi.
e.g. 
http://scruss.com/blog/2013/06/07/well-that-was-unexpected-the-raspberry-pis-hardware-random-number-generator/

But that is not an exclusive.

Thaddy

On 28-Jan-16 1:30 PM, Jonas Maebe wrote:
>
> Ondrej Pokorny wrote on Thu, 28 Jan 2016:
>
>> Regarding: http://bugs.freepascal.org/view.php?id=29526 (because I 
>> cannot answer on closed issues).
>>
>>>> Also: the entire state of the random number generator consists of 
>>>> regular global variables, so it is not safe to use it from multiple 
>>>> threads in parallel.
>>
>> Would it make sense to you to make random thread-safe? E.g. with the 
>> use of "threadvar" instead of "var" for the global variables in 
>> question?
>
> No. The Mersenne twister has a lot of state (about 2KB). Duplicating 
> this for every thread, along with associated slowdown, is not worth 
> it. It's better to use a class that encapsulates the state of a random 
> number generator and then instantiate this class for every thread.
>
>
> Jonas
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