Author: Robert Hyatt
Date: 07:39:10 12/24/98
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On December 23, 1998 at 00:56:41, Dave Gomboc wrote: >On December 22, 1998 at 15:15:29, José de Jesús García Ruvalcaba wrote: > >> Well, I tried to say exactly the opposite of what you think I think. >>Perhaps we have a language problem, I am not a native English speaker. Let me >>restate my point: while algorithms have improved, they have also adapted to >>faster hardware. >[snip] > >This is a very important point, if I may go off on a tangent. > >I've heard some comments from people to the effect that "if other people had the >hardware that the Deep Blue team did, they wouldn't be searching everything and >extending like they do now, instead they'd be using null move with r=2 just like >the rest of us". But you know, it's not exactly difficult to implement >null-move, it's been done many times before, and though the Deep Blue team >consists of a bunch of pretty bright people, it was their choice to do things >differently. I think it'd be fairly easy for them to test out a null-move >implementation, so would they really just ignore it? My opinion is that they >probably did give it a try and, at the nodes per second they were searching, >found the extra speed not worth the accuracy loss. > >Comments? > >Dave Gomboc I definitely think that technology drives the search *and* the evaluation. IE if you can only search 1-2 plies deep, you had *better* teach your evaluation something about 'forks' because it won't be able to find them with the shallow searches. But once you reach 4-5-6 plies, you can forget about forks because the search finds them, and evaluating them is not needed. This idea carries on to other parts of the tree. IE this is why I added singular extensions to CB a few years ago. I felt that we were going deep enough for normal positional type ideas, but that we needed to follow some forcing lines deeper than we were. I tried singular extensions somewhere around 1978 or so, and while they found some nice tactical plans, they cost me a ply. In 1978 we are talking about going from 5 plies back to 4. That hurt and I gave up on them and removed the code just before the 1978 ACM event. And I stayed away from them even after Hsu reported good results, because he had a *lot* more horsepower than I did and he could afford to lose the ply to gain the depth along selected lines. Once we hit the 1/2M node per sec speed, I reconsidered, added the code again, and was much happier dropping from 11 to 10 plies than I was when I dropped from 5 to 4 plies... micros are now getting to the speed point where this is perfectly doable...
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