CGAL users discussion list

[Francois Berenger <>]

If you seed a random number generator (RNG) with every time the same 
seed, you get every time the same sequence.

If you don't understand, just use the code provided by Doug.
The RNG is seeded only once by doing how he does.

On 06/22/2011 04:17 PM, sara Samadi wrote:
> I havent test your idea yet, but i think it is not important for
> compiler that initialization is in or out of for loop because the
> compiler translate the statement (CGAL::Random random) only one time.
> --- On *Wed, 6/22/11, Doug Epps 
> /<>/*
>  wrote:
>
>
>     From: Doug Epps 
> <>
>     Subject: Re: [cgal-discuss] CGAL::Random
>     To: 
>
>     Date: Wednesday, June 22, 2011, 5:04 AM
>
>
>     I believe (though i can't compile it right now) what Sylvain meant
>     was to do:
>
>     CGAL::Random random;
>     for (int t = 1; t<4; t++)
>     {
>     double randi=random.get_double (0.0, 1);
>     std::cout << "randi" << randi << std::endl;
>     }
>
>     Note how the CGAL::Random is OUTSIDE the loop, and so is in scope
>     for all 3 iterations of the loop, rather than being created for each
>     one.
>
>     My intuition is that the creation of the CGAL::Random object seeds
>     the random-number generator.
>     So you're getting the same thing over and over.
>
>
>     On Jun 21, 2011, at 9:50 PM, sara Samadi wrote:
>
>      > for (int t=1; t<4; t++)
>      > > {
>      > > CGAL::Random random;
>      > > double randi=random.get_double (0.0, 1);
>      > > double mandi=random.get_double (0.0, 1);
>      > > std::cout<<"randi="<<randi<<std::endl;
>      > > std::cout<<"mandi="<<mandi<<std::endl;
>      > > }
>
>
>     --
>     You are currently subscribed to cgal-discuss.
>     To unsubscribe or access the archives, go to
>     https://lists-sop.inria.fr/wws/info/cgal-discuss