Re: Am I misunderstanding random numbers?

[Taco Hoekwater <taco@...>]

Ignacio Burgueño wrote:
> On Tue, Mar 16, 2010 at 2:54 PM, Javier Guerra Giraldez
> <javier@guerrag.com>wrote:
>
> >  i guess that your Lua's math.random() is not stock Lua's.  if it were,
> > we should get the same numbers given the same seeds.
> >
> > can other members try this and see if everybody gets exactly the same
> > random numbers?  this is Kubuntu 9.04 x86_64 with Lua 5.1.4 default
> > install.
> I get the following, with Lua 5.1.4. Windows7 x64 (32 bit lua) and the same
> on Windows XP SP3.
>
> Seed: 3063121584 12 2356 6482 744
> Seed: 2428144928 12 2356 6482 744
> Seed: 3559301251 12 2356 6482 744
> Seed: 4287790062 12 2356 6482 744
> Seed: 2737803158 12 2356 6482 744
> Seed: 2458923424 12 2356 6482 744

I got similar problems a while back in luatex, which uses the coco
patches. For us, the problems seemed related to the Windows handles
threads/fibers: each new thread gets a totally fresh rand()
environment with a default seed value, regardless of earlier srand()
calls in the main program. Could this be something similar?


Best wishes,
Taco