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

Author: Don Dailey

Date: 14:30:40 01/06/98

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>>>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.

>Quite possible. Everyone knows that in the Deep Blue project they had
>the entire backing of IBM and were able to devote as much time as
>necessary to fine tuning their program, but I don't know what the
>situation was back then. Bob has often explained how he had had to do
>all of his debugging smack in the middle of an event because he couldn't
>just go around tinkering with his Cray program on a Cray whenever he
>pleased. Maybe they had a similiar problem then, I don't know.

>>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.

Hi guys,

Here is my take on Deep Blue and it's algorithms.  First of all their
approach is based on lots of hardware which gives them a HUGE problem.
If something is wrong with our software we quickly fix it.  If something
is wrong with their hardware they have a huge problem that will take
months to get to the next version.   So there is a lot of flexibility
we take for granted that they do not get.  What they have done is very
impressive indeed and took a great deal of engineering talent.

As far as the classic question about how would they do against the
best micro's on equal hardware?   First of all it's not easy to define
what equal hardware is at all.   But I'll take a stab and give you
my sense of the issues involved.

Let's use REBEL as representative of the best software available.
If you scaled Rebel up to do the same Nodes per second as Deep Blue
there would be no contest, Rebel would be a HUGE favorite.

But this is hardly a fair comparison, Rebel is a SERIAL program and
is clearly more efficient than a parallel program which tends to look
at many extra nodes to do the same amount of effective processing.

So let's "pretend" we can run the pure Deep Blue algorithm in SERIAL
mode and match up both Rebel and Deep Blue, let's say 2 million nodes
per second (and equal hash tables.)

The winner?   REBEL wins again!  But we are still being quite unfair.
Deep Blue is forced to accept compromises and inflexibilities that
REBEL does not have to deal with.  It's quite certain that many design
choices were optimized for the exact approach each side was using.
From Deep Blues point of view, the stuff in Rebel would be wrong to
attempt to implement in Deep Blue.

An example of this will suffice.  Until recently Deep Blue could not
even pick up repetition in the hardware portion of the search.  No micro
program would dare leave this out, it's a bad idea.  But at the time
choosing to leave it out seemed right for Deep Blue because it added
too much complexity to the chips that did the end node searching.
When we played them in Hong Kong they were quite afraid we might get
a draw (we did not) because there were long checking lines for us.
They were noticably disturbed by the possibility.

Well since then they have corrected this problem but there was no
easy fix.  It took a complete re-engineering of the chip and probably
at least a YEAR or more to go through the whole cycle.

The real bottom line here is that it is almost silly to compare the
two programs except on absolute strength.   Deep Blue could probably
not hold up MOST of top micro's if you tried to equalize everything
in this manner but it's no reflection on the Deep Blue team.   In
every way (except raw speed) the Deep Blue team is handicapped so you
can not expect them to compete with the highly tuned micro programs.

Would you compare a world class human sprinter to a cheetah and say
how fast would the Cheetah be if it were only human?

So does Deep Blue suck?   In rating points per node searched, YES.
In absolute strength of course NOT.  It's unclear (to me) if they
are much better than the very best micro's but I'm pretty sure it
would win a long match against any of them (this year anyway.)

Deep Blue's performance seems to be about as good as the top micro's
based on the few tournaments it's played in and the close (but very
short) match against Kasparov is a good indication that it's quite

Sorry Bruce, I know you didn't want to hear about this!   I carefully
avoided singing their praises or saying they sucked!

- Don

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