Looney Labs Icehouse Mailing list Archive

RE: [Icehouse] IGDC Summer 2007 Rankings

  • FromAndrew Plotkin <erkyrath@xxxxxxxxxx>
  • DateWed, 26 Sep 2007 16:29:28 -0400 (EDT)
On Wed, 26 Sep 2007, Doug Orleans wrote:

Unfortunately, the Ranked Pairs method does not say what to do when
all the wins in a tied group are equal[1], which also happened here:
Pylon beat Zamboni Wars by 2, Zamboni Wars beat Penguin Soccer by 2,
and Penguin Soccer beat Pylon by 2.  This is where Zarf's tiebreaker
(which is not part of the standard Ranked Pairs method) comes in, by
looking at which games beat more other games, or lost to fewer, but
I'm still a little fuzzy about exactly how and when this tiebreaker is

I'm not applying it during the RP algorithm, but afterward.

From Tim Hunt's post:

=> pylo > subd > zamb > geom > moon > mart > trip

Margin at 2
Zam > peng  )__ self-inconsistent, need to break tie
Peng > pylo )
pyl > zamb  *ignored - consistent with established results
Moon > subd *ignored - inconsistent with established results

What my (new) script does in this case is to accept pyl>zamb (already in the table), ignore Moon>subd (inconsistent with the table), and then discard *both* of Zam>peng and Peng>pylo. There is no tiebreaking at this stage. The two facts can't be made to fit, so discard then and move on.

I don't actually know what the voteengine script (which I used in 2005) does in this case. But I never added my tiebreaking rule to it. I only applied it by hand, afterwards.


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