Author: Robert Hyatt
Date: 12:46:34 07/23/02
Go up one level in this thread
On July 23, 2002 at 11:48:02, Uri Blass wrote: >On July 23, 2002 at 11:36:36, Robert Hyatt wrote: > >>On July 23, 2002 at 10:40:00, Uri Blass wrote: >> >>>On July 23, 2002 at 10:06:18, Robert Hyatt wrote: >>> >>>>On July 23, 2002 at 04:18:46, Bo Persson wrote: >>>> >>>>>On July 23, 2002 at 00:32:44, K. Burcham wrote: >>>>> >>>>>> >>>>>> >>>>>>Some say that Deep Blue could analyze 200,000kns in some positions. >>>>>> >>>>> >>>>>This is more the *average* speed of the system. I have seen figures of up to 1 >>>>>billion nodes per second, in favourable (for speed) positions. >>>> >>>> >>>>I have a paper written by Hsu and Campbell that says their peak speed during >>>>the 1997 match was 360M for a single move. Of course, the machine was capable >>>>of bursts to 1 billion nodes per second, which I am sure it hit at times >>>>since that only required that all 480 chess procesors be busy at the same >>>>instant. >>>> >>>> >>>> >>>>> >>>>>This doesn't say, of course, what the search speed would have been in your test >>>>>position. Could have been 150M nodes/s, could have been 950M nodes/s... >>>>> >>>>> >>>>>The comparison of speed is also somewhat flawed by the fact that Deep Blue was >>>>>explicitly designed to be fast (as in nodes per second), which most of the other >>>>>programs are not. >>>> >>>> >>>> >>>>I don't agree with that. DB was a two-fold design: (1) fast, due to special- >>>>purpose hardware (2) good, due to adding whatever they though necessary into >>>>the hardware. >>>> >>>>Software programs don't have the option (2) available to them, so to keep >>>>option (1) viable, they compromise. DB didn't have to. >>> >>>In order to have good evaluation function you need to know what is good. >>>Programmers today know better than what they knew in 1997. >>> >>>Uri >> >> >>No we don't. Chess has been chess for 100 years. 20 years ago we knew what >>we "needed". > >No we did not. OK... I will rephrase that. 20 years ago _I_ knew what we needed to do in the evaluation, but couldn't do due to cost. My evaluation for Cray Blitz is _very_ close to the evaluation I currently have for Crafty. The pawn stuff is effectively identical except for some endgame details. But weak pawns, passed pawns, outside passed pawns, candidate passed pawns, all that was in Cray Blitz in 1983. > >Prorammers know better today because they have more experience in chess >programming relative to the experience that they had some years ago. Experience in "chess programming" is not the issue. "experience in chess" is more important... > >Finding the right evaluation and deciding what to evaluate is the problem. It never was the problem for me. I have _never_ had trouble finding new eval terms to try. I have had great trouble making the good ones affordable so that the could actually be used in the program... > >The evaluation of the top programs of today is better relative to the evaluation >of some years ago. Ask the top programmers these questions: 1. When did you first evaluate passed pawn races? 2. When did you first evaluate outside passed pawns? 3. When did you first evaluate pawn majorities, candidate passed pawns, and the like? 4. When did you start to be sophisticated in evaluating weak pawns, vs just simple rules for backward and isolated pawns? etc... I did all those 20+ years ago. I _know_ when micros started doing outside passed pawn code and it was fairly recently. Because when I first started doing it again in Crafty in 1994-1995 it used to beat the commercials in endgames right and left when that was important. Ditto for the bishop trapped at a2/h2/a7/h7. Ditto for other ideas that used to be considered too expensive but were not. The machine I used made those very cheap to do and so we did. But I wasn't using a micro in the 80's and early 90's... > >Uri > > > And we knew what we could "afford". Today, what we "need" has >>not changed one iota, but what we can afford has changed drastically. DB just >>got to this point way before we got there...
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