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Subject: Re: EGTB access and playing strength

Author: Robert Hyatt

Date: 18:41:44 01/29/06

Go up one level in this thread


On January 29, 2006 at 12:34:55, Mark Rawlings wrote:

>On January 29, 2006 at 10:45:28, Robert Hyatt wrote:
>
>>On January 29, 2006 at 09:52:57, Kurt Utzinger wrote:
>>
>>>On January 29, 2006 at 09:38:56, Majd Al-Ansari wrote:
>>>
>>>>I have a completely different result.  I see quite a big difference and many
>>>>"won" games are now won instead of drawn.
>>>
>>>      Please be good enough to present those results
>>>      here. This would be of great interest.
>>>      Kurt
>>>
>>>I have checked out quite a few games
>>>>and I will say that EGTB's greately improve endgame play for Rybka, and plug a
>>>>lot of holes.
>>>
>>>      This is contrary to long experience with other engines
>>>      where you can almost see no difference regarding overall
>>>      score after playing some hundred games.
>>>      Kurt
>>>
>>> EGTB are especially important if the other side has them.  Not
>>>>having them will leak a lot of points.  Still there is quite a ways to go for
>>>>Rybka when endgames are concerned.  It still plays some endings horribly.  But
>>>>the gaps are getting smaller and smaller and I am very interested to see how
>>>>Rybka will be with beta 14 (EG knowledge added).
>>
>>
>>One note:
>>
>>Playing EGTB vs NoEGTB to see if EGTB helps is probably the wrong way to measure
>>the experiment.  It is more useful to take a known good program _with_ EGTBs,
>>and play your favorite engine against it, with your engine not using 'em, then
>>playing again with 'em.  If the opponent doesn't have 'em, then your not having
>>them might not expose the problem as well as making sure your opponent can
>>always win those tricky cases and you now have to rely only on your eval to hang
>>on...
>
>
>One thing that makes a comparison difficult when you play a program with and
>without tablebases is that there's probably a lot of basic endgame knowledge
>that  is not programmed into the engine because the author knew he was going to
>use tablebases.  For example, a program may not have the knowledge to win kbn vs
>k without tablebases, but the author could have added the extra code if he
>wanted to.  I assume that some endgame knowledge was removed from crafty years
>ago when tablebases became common.
>
>Tablebases vs no tablebases would be a good thesis topic for someone!
>
>Mark


Actually, I never removed anything at all.  Crafty can still win KBN vs K, or KQ
vs KR, or KP vs K (when it is winnable) easily without endgame tables.  I always
assumed that not everyone would have them...



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