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Subject: Re: Benefit of tablebases seems to be 2 points!?

Author: Jeremiah Penery

Date: 13:42:40 10/16/99

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On October 16, 1999 at 10:24:23, James T. Walker wrote:

>On October 15, 1999 at 09:53:51, Jeremiah Penery wrote:
>
>>On October 15, 1999 at 03:44:30, Ed Schröder wrote:
>>
>>>>Posted by Marcus Kaestner on October 14, 1999 at 04:01:40:
>>>>
>>>>in chessbits 3 i´ve made a test with the nunn-endgames (10 endgame-positions
>>>>played with both sides). every program one time with, one time without tb´s
>>>>
>>>>after abaout 140 games
>>>>h7.32 earned +5 elo for the tb-version
>>>>n7.32 earned +12 elo
>>>>
>>>>far the best was crafty 16.13 with +65 elo, topping even the score of hiarcs
>>>>7.32tb
>>>>
>>>>marcus
>>>
>>>Take this into account: Some programs may have so much chess knowledge in their
>>>programs that (the current) TB's have zero effect in the end. This will change
>>>as soon as the 6-man TB's (and up) will come, no doubt..
>>
>>Definitely.
>>
>>>Other programs are developed to 100% rely on TB's and therefore have very few
>>>(or nothing) chess knowledge inside because there is no need for that. I don't
>>>know in to what extend this is true for Crafty but I am confident Bob will
>>>tell you.
>>
>>I don't think there are any programs developed to "100% rely on TB's" so that
>>they wouldn't have any knowledge about the endgame.  Whatever search/eval they
>>have will still be quite good (At least in endings where TBs would affect things
>>- 5 piece or less), it's just that the TBs provide 100% accuracy.
>>
>>>As a result you can not compare the value (elo gain) of TB's in this way as
>>>it will depend of what is already inside a program (or not).
>>>
>>>Rebel knows the most important ones such as (by head):
>>>
>>>- KRK
>>
>>Yes, this one is easy.
>>
>>>- KNNK
>>
>>Of course, this is always a draw.
>>
>>>- KBNK
>>
>>This one's interesting, but not really that difficult.
>>
>>>- KPK
>>
>>This is pretty easy, too.
>>
>>>- KRPKR
>>>- KNPKN
>>>- KBPKB
>>>- KQPKQ
>>
>><lumping these last 4 together>
>>I'm a bit skeptical about some of these.  I'm sure it may play even 90%
>>accurately in these endings, but I'd be willing to bet it couldn't win 100% of
>>winnable positions from these endings (especially KRPKR and KQPKQ) against an
>>opponent with the TBs.
>>
>>>I am sure this list is not complete. Of course the bad-bishop situation is
>>>covered too. Some others are not covered such as KQKR (Hi Jim!) for which
>>>Rebel will rely on TB's in the future.
>>
>>I'm sure Rebel could easily win KQKR without TBs, even against an opponent with
>>them.  It's an easy ending for computers.
>>
>>Jeremiah
>
>Hello Jeremiah,
>I wish this were true!  See the (Hi Jim) above.  I brought this up to Ed last
>week.  I saw Bob's post concerning this ending as trivial since Crafty could do
>it easily.  I decided to test this and gave Crafty a Mate in 28 against Hiarcs
>7.32.  Crafty with no tablebases mated in 36 moves against Hiarcs with
>tablebases.  When I gave this to Rebel it failed badly.  In fact at the 50th
>move according to Hiarcs it was at "Mate in 28".  Right where it started even
>though at one point it had it down to about mate in 17.  This is about the same
>area where humans were found to have problems with this ending.  It seems if
>they could get past the mate in 15/16 area they could complete the mate.
>Problem is most could not break this "Barrier".
>Jim Walker

Oh, my.  I wonder why Rebel failed this so badly.  Since it seems to be quite
trivial for Crafty, but not so for Rebel, I wonder how other programs do at this
ending.

Thanks for the information. :)

Jeremiah



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