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Subject: Re: A match in DRAUGHTS , Too many DRAWS !!!

Author: martin fierz

Date: 05:27:21 02/08/01

Go up one level in this thread


On February 08, 2001 at 06:30:14, Tony Werten wrote:

>On February 08, 2001 at 04:24:11, David Blackman wrote:
>
>>On February 07, 2001 at 16:41:28, Tanya Deborah wrote:
>>
>>>
>>>
>>>Hi!
>>>
>>>I am playing a new match in checkers between the 2 strongest Spanish checkers
>>>programs of the world...
>>
>>Just curious, is "Spanish checkers" the same game as "Polish Draughts",
>>"International Draughts", "Damen" etc?
>
>She could have meant 2 spanish programs playing polish checkers :)
>
>I think it's true for the other coutries as well, but the game played in Holland
>is international draughts.
>>
>>http://www.multimania.com/nic55/dames/dames2.htm
>>
>>They say it is played in
>>"most French-speaking countries (France, Belgium, Switzerland, Canada, and the
>>African continent) and also in the Netherlands, and in the ex-soviet union
>>countries."
>
>If I remember correctly, in the SU they let the children start with checkers to
>get some ideas about the tactics, before switching to draughts.
>
>>
>>This is the game on the 10x10 board.
>>
>>According to people who have tried, it is a bit harder to write a strong program
>>for it than for chess. Perhaps it should be the next big board-game programming
>>challenge, now that chess programs are more or less in reach of the top human
>>players, and Go still seems much too hard.
>
>Depends on what you call difficult. In checkers ( and draught ) there seems to
>be no additional strength from searching deeper anymore, only from better
>evaluation. Which is a bit harder to achieve. It also means that a faster
>computer doesn't give you a stronger computer automaticly.

this is not true. i performed some self-play experiments with my computer
checkers program, i used a version searching to a fixed depth n to play another
version searching to depth n-2, in 282 game-matches with the results

depth win%
5-3   78.9% (+196=53-33)
7-5   72.0% (+153=100-29)
9-7   77.5% (+181=75-26)
11-9  65.8% (+130=111-41)
13-11 68.1% (+134=116-32)
15-13 66.3% (+119=136-27)
17-15 60.8% (+89=165-28)
19-17 58.9% (+78=176-28)
21-19 54.8% (+60=189-33)

yes, these are diminishing returns for deeper searches, but no, it is not true
that searching deeper doesnt help. i also tried taking out some very important
knowledge from the eval of the deeper searching program, expecting the shallower
program to beat it from some search depth on - which was not the case. the
result for the deeper program did get worse, but it always won. the statistical
errors on the above numbers are about 2%, so 78.9+-2.0%.
there was a chinook paper once, which reported diminishing returns too, but that
only had 20-game matches i think and huge error margins - too large to claim
anything.

cheers
  martin



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