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Subject: Re: Deep Blue test positions vs todays programs

Author: Robert Hyatt

Date: 14:54:13 09/28/05

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On September 28, 2005 at 14:38:39, K. Burcham wrote:

>
>
>Do you know of a position in the Deep Blue vs Kasparov games, that todays
>programs cannot find? I am trying to find a position that not even one program
>today can find this position without very long search. I will conclude that this
>position cannot be found with default knowledge. I am looking for a position
>that I can see that no program of today, with default settings will find this
>Deep Blue game position without leaving one of my programs running for a very
>deep search.
>
>kburcham


I am almost certain that, by definition, such a move is not going to be found.
Because many moves (both good and bad ones) are made for the wrong reasons.  And
most likely, unless we find some wild tactical position that simply confuses
current searches completely, but DB was able to work thru it, then most any
other kind of position is not going to be useful.

For example, how many times have we seen problem positions where it is "white to
play move XXX and win".  And one (or more) programs play move XXX with a +
score, that is convincing.  And one (or more) programs play move XXX with a -
score, which means it is playing the right move for the wrong reasons.  Ditto
for programs that also play move XXX with a score of 0.0 thinking it is the only
way to avoid a loss, when it is the right way to actually win.  Most positions,
other than those ending in mate, or with huge material wins, rely on both search
and evaluation.  And a program that is a bit top-heavy on king safety might find
more of Tal's favorite moves than a program with a more conservative
(Karpov-like) evaluation.  Yet both are equally strong overall.

Finding these kinds of positions is _very_ difficult, because there are so few
DB 2 (last match) games available.  In fact, I only know of 6.  Which limits the
number of total positions available to a very small set.  The likelihood of
finding such a position in that small set is _very_ small to say the least.  For
example, many criticized the h5 move by DB in either game one or two (I don't
remember and don't have the logs handy).  Kasparov said "that was the only move
to play".  Later he questioned the move as being un-computer-like, until someone
pointed out that some version of Deep Junior would play the same move.  So as
you can see, finding a bad move by DB that other programs avoid, is just as hard
as finding a good move by DB that other programs can't find.  Because with so
many programs, there is a high probability that one or more of such a big group
will choose any "reasonable" move that is possible, including the one played by
a very strong computer like DB.

Wish the answer was better, but unfortunately since they rolled up the sidewalk
and went home after the match, we are left in a near-vacuum of data about the
thing (DB2).  Deep Thought certainly played a lot of published games, but it was
100x (or more) slower than DB2, and also had a much simpler evaluation than DB2.
So even looking at those doesn't say much about how DB2 would compare to
anything...




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