[Kde-games-devel] Reproducing random numbers

[Ian Wadham]

On Wed, 15 Apr 2009 8:28:04 am Albert Astals Cid wrote:
> A Tuesday, 14 of April de 2009, Ian Wadham va escriure:
> > On Mon, 13 Apr 2009 9:57:09 pm Albert Astals Cid wrote:
> > > Reading the code and the documentation is what i understand too
> > > (KRandomSequence with seed gives a "known" random sequence), if you
> > > find this to be false i would qualify it as a bug.
> >
> > Agreed, but see Kevin's point about cross-platform and future versions
> > of KRandomSequence.
>
> From what i see KRandomSequence is totally self contained (calculates
> itself the random values) so that should not be a problem, right?
>
Not right now, but what if somebody decides to tweak the internal
constants to yield a statistically-improved pseudo-random sequence
of numbers?  Or what if someone publishes a new, ground-breaking,
must-have RNG algorithm (the Ferrari-Hummer algorithm :-))?  Those
changes would very probably alter the numbers produced from a given
seed, and so all the recordings built in to demos and tutorials in
KGoldrunner would have to be re-created (at least).

It is easy enough to record and replay the RN stream that was used at
recording time, so why take a risk?

Cheers, Ian W.