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Subject: Re: LCT II Fin4, Deep Thought, and Deep Blue (was Re: LCT II results...)

Author: Bruce Moreland

Date: 20:07:27 01/05/98

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On January 05, 1998 at 17:53:07, Albert Silver wrote:

>Deep Blue sucks??? That isn't exactly what I said, and if that's the
>impression I gave, then I'd like to clarify. You say you turned off you
>endgame databases. Fine, but what does that have to do with knowledge?

Ok, please pardon me, I didn't consider what my words implied.

I asked a question, and if anyone has an idea, that'd be great.  I am
afraid that we'll go straight to the traditional "How good would DB be
vs program X" discussion, where X is Hiarcs, Rebel, Genius, or Fritz,
rather than talking about the issue I raised.

>Disable Ferret's knowledge of the game (or at least most of it) and then
>run it through. How many plies until 59...h5 is clearly and materially
>lost? Not evaluated lost, but materially lost. Why do some programs find
>the solutions to problems faster than others? Is it just because they
>search deeply quicker than others?

There are people who might claim that their programs are jam packed with
knowledge about stuff like this, but I won't, because mine isn't.

It tries to understand passed pawns, king position, rooks behind
passers, connected pawns, rook on the 7th, and the like.  It has KRP vs
KR tables, and various other tables, but like I said, I turned that off.
 With that stuff off, it knows that some KRP vs KR positions are likely
draws, but not much else.

This is hardly special, and none of this may matter here very much.  It
seems possible that this position is resolvable by pure search.

To answer your specific questions, first it understands that ... h3 is
drawn (returns a draw score), pretty quickly.

If you play ... h5 and let it search for white, it also seems to
understand that black has real problems, likewise pretty quickly.  It
starts out liking Kg5 at +1, and figures out that something is either
wrong with this or looks wrong with this at about 2.0 seconds, and by
2.7 seconds into this search has decided that it's going to go with Ke5.
 This starts out at better than +1 and goes up to +2 at the end of a
minute, and is based upon being a pawn up.

I've run LCTII on about a hundred different versions, and probably 90%
of them have gotten this in less than 35 seconds.  The longest any of
these versions took was 101 seconds.  This is all on a P6/200.

I didn't tune for this problem, nor have I ever even really looked at
it.

So I wonder why DT didn't get it.  Did they have a bug?  Were they in
time pressure so bad that they couldn't spend a few seconds to find it?
Is their search doing so much full-width stuff that the micros are
actually out-searching them here?  Do they have an evaluation hole?  I
have no idea.

>If that was the case, then a program
>like Hiarcs should underperform in test suites (for example) compared to
>power searchers in every test, every single time. That's not the case
>obviously. Take the example of Junior's game against Comet in which it
>played the losing 47...Rxd3. I fed the position after 47.Kg1 to Fritz 5
>and watched to see how deeply it had to go to see that Rxd3 is LOSING
>(not just when it would choose another move). After 13 plies it
>announces that Rxd3 draws, and after 14 plies it sees that this loses
>outright. I then let Hiarcs 6 look at it, and after 6 plies it says that
>Rxd3 draws and after 7 plies it says that it loses. I'll admit this
>example is unusually extreme, and that there are opposite examples of
>Fritz's searching showing results far faster than Hiarcs. While this
>clearly argues in favor of knowledge based programs, I also don't
>believe that every knowledge ladden will reach the solution at this same
>depth (some may do it at a shallower depth, and some may require an
>extra ply or so). The difference would then be not just a matter of
>knowledge, but also in how this knowledge was administrated (or
>prioritized). My argument wasn't actually about Deep Blue and Deep
>Thought, though I used them for the sake of examples, but on how
>knowledge is used in programs and how it is prioritzed in the evaluation
>function. If a program is juggling 300 elements in a position but
>doesn't know which ones to prioritize, then it's knowledge is useless,
>and might even be a hindrance. But to say that Deep Blue sucks?.... I
>couldn't disrespect Kasparov that much. :-)

I may be wrong, but I don't think this is a knowledge problem.  I think
straight search finds it just fine.  If DT didn't find it, it raises
questions about their search, or perhaps they simply didn't have enough
time to find it.  It'd be interesting to find out what happened here.

bruce



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