Re: Am I misunderstanding random numbers?

[Javier Guerra Giraldez <javier@...>]

On Tue, Mar 16, 2010 at 11:17 AM, Christopher Eykamp <chris@eykamp.com> wrote:
> I'm running on Windows, embedded in a C++ app.  The chances of a re-seed
> seem minimal, as the two lines I posted are executed one after the other in
> the same file.
>
> I have temporarily resolved my problem by overwriting the random function to
> call my C++ program and use it's random function, which seems to be...
> well... random.
>
> If the seeds were the same, I would expect the results I see, but they're
> clearly different.

i've just tried this:

function tr(seed)
  math.randomseed( seed )
  print ("Seed: "..seed,
math.random(10000),math.random(10000),math.random(10000),math.random(10000))
end

for _,s in ipairs
({3063121584,2428144928,3559301251,4287790062,2737803158,2458923424})
do
  tr(s)
end

and i get:

Seed: 3063121584        2331    1179    6134    7741
Seed: 2428144928        9074    3329    5507    8307
Seed: 3559301251        1739    4278    5885    8691
Seed: 4287790062        6352    1754    759     588
Seed: 2737803158        5587    8387    1486    6766
Seed: 2458923424        4302    7992    5852    5221

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.


-- 
Javier