Re: [Bug-gnubg] Holding games

[Neil Kazaross]

I'll send along a few examples of positions that I consider basic holding
games that are VERY common and would enhance GNU if it were a better judge
of equity in them.

..neilkaz..
----- Original Message ----- 
From: "Joseph Heled" <address@hidden>
To: "Albert Silver" <address@hidden>
Cc: "'Ian Shaw'" <address@hidden>; "'GNUBackgammon bug reporting'"
<address@hidden>; "'Neil Kazaross (E-mail)'" <address@hidden>
Sent: Sunday, June 22, 2003 7:24 PM
Subject: Re: [Bug-gnubg] Holding games


>
> I suspect that just holding an anchor would mark too many positions.
> Probably many you would not consider as a "holding game".
>
> My benchmark shows that 46.5% of the positions are classified as holding
> by your definition. The error rate definitely supports the claim that
> GNUbg errs more in those positions.
>
> nonholding (57431 53.43%) 0.009573
>     holding (50054 46.56%) 0.011446
>
> -Joseph
>
> Albert Silver wrote:
> > I was gone this weekend so couldn't respond earlier.
> >
> >
> >>>I don't think we need that many to make the case, but if you can
> >>>generate some positions I'll put them through sagnubg.
> >>>
> >>
> >>I agree. Still waiting for a clear cut definition of a holding game
> >
> > from
> >
> >>you guys. How about "No checkers on points lower than 18, decent
> >
> > contact
> >
> >>(say at least 3 points separate the back checkers), and no blots in
> >
> > the
> >
> >>area of contact?
> >
> >
> > I'm not sure I understand your desription. As I see it, you have a
> > holding game if you have an anchor on my 3-pt, 4-pt, 5-pt, or 7-pt (my
> > bar point). For example:
> >
> > GNU Backgammon  Position ID: 4HPDAQbg2+DBAA
> >                  Match ID   : cAkAAAAAAAAA
> >  +13-14-15-16-17-18------19-20-21-22-23-24-+     O: GNU
> >  | X        O  O  X |   | O                |     0 points
> >  | X        O  O  X |   | O                |
> >  | X           O    |   | O                |
> >  | X                |   | O                |
> >  |                  |   | O                |
> > v|                  |BAR|                  |     (Cube: 1)
> >  |                  |   | X                |
> >  |                  |   | X                |
> >  | O                |   | X                |
> >  | O           X  X |   | X     O          |     On roll
> >  | O           X  X |   | X     O          |     0 points
> >  +12-11-10--9--8--7-------6--5--4--3--2--1-+     X: Albert
> >
> > Here the Os have a 3-point holding game, and the Xs have a bar-point
> > holding game. Of course, one of the big issues (highlighted by Neil) is
> > that the bots tend to overestimate positions where the holder has a 3rd
> > rear checker such as:
> >
> > GNU Backgammon  Position ID: 4LnhACPgbfBgIA
> >                  Match ID   : cAkAAAAAAAAA
> >  +13-14-15-16-17-18------19-20-21-22-23-24-+     O: GNU
> >  | X        O  O  X |   | O              X |     0 points
> >  | X        O  O  X |   | O                |
> >  | X           O    |   | O                |
> >  | X                |   | O                |
> >  |                  |   |                  |
> > v|                  |BAR|                  |     (Cube: 1)
> >  |                  |   |                  |
> >  |                  |   | X                |
> >  | O                |   | X                |
> >  | O           X  X |   | X     O          |     On roll
> >  | O           X  X |   | X     O        O |     0 points
> >  +12-11-10--9--8--7-------6--5--4--3--2--1-+     X: Albert
> >
> > I wasn't too sure about what was meant with " no blots in the area of
> > contact". Do you mean if the blot on 1 was on the 5 point instead? If
> > so, it would still be a 4-point holding game, even if it could change.
> >
> > Albert
> >
> >
> >
> >>>Neil Kazaross has made the observation that "most bots tend to cube
> >>>holding games a bit late". If an expert of Neil's calibre has noted
> >
> > this
> >
> >>>feature then I'm inclined to take it seriously. One of the best ways
> >
> > to
> >
> >>>improve gnubg must be to identify classes of position where it is
> >
> > weak.
> >
> >>>Expert opinion will be very valuable for this.
> >>>
> >>
> >>Agreed.
> >>
> >>-Joseph
> >>
> >>
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > Bug-gnubg mailing list
> > address@hidden
> > http://mail.gnu.org/mailman/listinfo/bug-gnubg
> >
> >
>
>