[plt-scheme] Re: please help with generating random permutation

From: Noel Welsh (noelwelsh at gmail.com)
Date: Sun Sep 13 15:13:36 EDT 2009

FWIW, here is how I would characterise the problem:

Fairness means that over a suitable interval (5 weeks perhaps) the
probability of drawing a M,T,W,Th, and Fri is 1 - e, for some choice
of e.

For e of zero the algorithm is trivial
For e > 0, the algorithm is also trivial :-)


On Sun, Sep 13, 2009 at 5:40 PM, keydana at gmx.de <keydana at gmx.de> wrote:
> So I proposed (at least) the following possible changes (there's no
> reactions yet):
> - take out the taking into account of the previous week ("back to random")
> - add the preferences (less random, but hopefully more fair)
> - do the drawings for 2 weeks at once, having as a constraint that as few
> people as possible be drawn twice (given the fact that we have less than 10
> possible "victims"). Perhaps this is even the best combination of randomness
> & fairness (it would be random but ALSO seem quite fair I guess)
> Ciao
> Sigrid

Posted on the users mailing list.