[computer-go] A new pairing system idea for CGOS

[Chris Fant]

Seems like for scheduling purposes you would take the ranking of each
player and add some amount of noise to it.  That way, you are still
using the ranking info in a meaningful way but also making it
non-deterministic.


On 10/5/06, Don Dailey <drd at mit.edu> wrote:
> I'm not sure all the people here appreciate the beauty of the swiss
> system or how it actually works.  It has properties that really lend
> itself to being a nice scheduling algorithm.
>
> One property that is very good is that you always play someone with
> the same score as yourself.  If you've won 4 games in the tournament,
> you will play someone else who has won 4 games.  If you have lost all
> your games so far, you will play someone else who has lost all his
> games.   That means you will gravitate towards players near your own
> strength, a feature that CGOS aspires to.
>
> Normally, you always play the top half against the bottom half within
> point groups.  The top player in the tournament would play the top
> player in the bottom half in the first round.  After that, you will
> essentially have 2 sub-tournaments if you think of this recursively.
> A tournament of first round winners, and a tournament of first round
> losers.  But in each sub-tournament you again pit the top half against
> the bottom half.   The infinite series you mentioned.
>
> As someone pointed out, this is a deterministic algorithm.  I do have
> some concerns about this when CGOS stays static for a long period
> of time.  A simple solution is to start each tournament with random
> rankings.
>
> This of course creates the possibility that you will get situations
> like the top 2 players meeting in the first round.  We could take this a
> step farther by randomizing the top and bottom half separately.  This
> will effectively kill the determinism while preserving most of the
> beneficial properties of correct rankings, but not completely.
>
> For instance you might still get a first round match between opponents
> who are very close in strength, which is not what you want in the first
> round.  A swiss is designed so that the distance in strength between
> opponents should converge in the later rounds assuming no upsets.  Or
> looking at if from the other side, it has the characteristic that your
> greatest mis-matches occur in the first round, assuming no upsets.  With
> each round, the amount of mismatch is cut in half.
>
> With correct pairings you would almost never get a situation where Mogo
> plays random.   Even with randomized top and bottom halves this would
> happen only occasionally,  almost soley based on Mogo losing it's first
> round game to a player in the bottom half or random beating a player in
> the top half, both events are extremely rare.
>
> - Don
>
>
>
>
> On Thu, 2006-10-05 at 16:01 -0700, steve uurtamo wrote:
> > > The Swiss mechanism won't be visible, it will happen
> > > behind the scenes
> > > and would be used as a pairing device only.    All
> > > you would see is
> > > opponent getting paired from round to round in a
> > > fair way.
> >
> > honestly, i think that this is a great idea.
> >
> > it approximates the "infinite sequence of swiss
> > tournaments", which means that it becomes a metric
> > that is as good as the swiss tournament system.
> >
> > s.
> >
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