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Subject: Re: Endgame code instead of Tablebases

Author: Dave Gomboc

Date: 15:04:04 04/16/99

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On April 16, 1999 at 17:47:28, KarinsDad wrote:

>On April 16, 1999 at 17:18:07, Dave Gomboc wrote:
>
>>
>>So KarinsDad (or whatever your real name is :), are you suggesting that such a
>>rule base be built using the tablebase info, or are you suggesting it be
>>constructed without access to a tablebase?  If the former, what would be the
>>point?  We already have perfect information that fits on hardware worth a couple
>>of hundred bucks.  If the latter, how?
>>
>>Dave
>
>Dave,
>
>What happens when the tablebases get up to 6 pieces and then 7, etc. Will it
>still fit on a couple of hundred bucks of hardware (and last I heard, some of
>the 5 piece tablebases were not perfect)?

By that time, yes, they will.

>Your second question is like "Why would you climb Mount Everest?". There could
>be multiple reasons and different reasons for different people.

Let's state flat out that I am not the sort to climb Mount Everest just because
it is there.  (Someone (Berliner?) once had a program called JBIIT! :).

>Let's not restrict the problem to tablebases, but let's include Opening books.
>Would you prefer your program to be GM level at opening play due to calculations
>or due to an opening book? Which method is more adaptable to theoretical
>novelties and which method would be more likely to result in a theoretical
>novelty?

There is a difference between compressing perfect play and innovating.  The
little actual work I have done in computer chess has been in the area of
automated opening repertoire construction.  (This can be contrasted with the
large amount of goofing around I have done with computer chess. :-)

>If you can find algorithms to solve the simple (relatively speaking) endgame
>problems, wouldn't that be a step towards solving more complex ones or even
>making the search/evaluation more sophisticated?

You haven't convinced me that it would be.

>The how is a totally different matter. That is why I brought up the question in
>the first place. If I knew exactly how, I would put this into my program and
>thumb my nose at all of those fancy programs that are limited to 5 piece
>tablebases. It is extremely difficult to solve for some cases (I do not deny
>this), but I also do not throw in the towel and say, "Oh well, we have
>tablebases, why do we need that?".

Tablebases encapsulate (roughly) perfect information.  That's about as good as
you can do.  If you want to construct a decision tree that decides which
positions are mates in 52 and which are mates in 173, feel free, take an ID3
engine or whatever and hammer at a tablebase.  The decision tree it spits out is
extremely unlikely to be of much use to a human chess player, though, so I don't
see a particular purpose in doing so.  If you just want to classify "win/draw",
well that would work, but how will you guarantee that progress is made?
Intermediate levels of resolution are possible, but since we have perfect
information, I see no particular reason to give it away.

>I would think that since most of us programmers are not GMs and therefore do not
>have good endgame technique ourselves, that the first place to examine is the
>current tablebases. It would be easier for us to dissect those with a program
>than it would be to figure out algorithms on our own.

It would be easier to grab a book like "Levenfish and Smyslov: Rook Endings" and
become a GM! :-)

>Also, if you save hard disk space by calculating the best moves on the fly and
>minimizing the tablebases that we do have (as per my earlier posts), then the 6
>and 7 piece tablebases will also be smaller and we may find certain ones of
>those that are more easily solved via a 4 piece or 5 piece table (if we can
>re-use the algorithms).

Calculating the best moves on the fly is something that would have to be done
quickly, i.e. in less than the amount of time the disk I/O you are replacing
would take.  Is this possible?  Perhaps.  Of course, if your tablebases are
preloaded into memory (like Chinook) then you will have a very tough time
searching faster than a hash table lookup.

>So, you tell me. Will this take a lot of work similar to the CAPPS (spelling?)
>project? Yup. Will this help make the endgames of programs stronger in the
>future? Probably. Do we know exactly how to do it? No. That's what this forum is
>about: discussing possibilities.
>
>KarinsDad :)

I'm discussing reasons why a possibility has remained "a possibility" for a long
time.  What's wrong with that? :-)

Dave



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