Author: Peter McKenzie
Date: 20:36:17 06/09/00
Go up one level in this thread
On June 09, 2000 at 19:14:52, Oliver Roese wrote: >On June 09, 2000 at 15:11:00, blass uri wrote: > >>On June 09, 2000 at 13:59:44, blass uri wrote: >> >>>On June 09, 2000 at 12:11:16, Ernst A. Heinz wrote: >>> >>>>>[D]8/8/Pk5K/2p5/2P1pp2/8/5P1P/8 w - - 0 1 >>>>> >>>>>Programs cannot see at evaluation time that black is winning because of >>>>>unstoppable pawn. >>>>> >>>>>If I give them to analyze at 1 ply depth they give a big advantage for white. >>>> >>>>What do you mean by "big advantage"? >>>> >>>>"DarkThought WCCC'99" knows about White's unstoppable passed Pawn >>>>on h2 and it also knows about the potential breakthrough of the >>>>two Black Pawns on e4 and f4. Both somehow cancel each other out >>>>in the static evaluation such that the overall score is just the >>>>+1 material advantage of White. >>>> >>>>=Ernst= >>> >>>Some other programs gave more than +2 for white and in one of the cases(I think >>>it was hiarcs7.32) they gave even about +7 pawns at 1 ply depth. >>> >>>Uri >> >>Here are some scores of chess programs at depth 1 >> >>chessmaster6000(7.21) >>Hiarcs7.32(7.18) >>Fritz5.32(6.16) >>Genius3 depth 1 with selective search=0(5.39) >>Rebel century1.2a(4.36 and the score at depth 2 is even 7.76 and only at depth 3 >>becomes negative) >>Junior5.9 (3.41) >>Crafty17.10(2.97) >>CometB20(2.80) >>CometB11(2.20) >>Junior4.6 (1.78) >>Exchess2.51(0.79) >> >>No program can see that white is losing at evlauation time or even at depth 1 >> >>Uri > >How would a human look at the position? >It would notify that both white and black have unstoppable passers/candidates >and a directed search is required to see, who is the winner. >"Deep Thought" evaluates it this way, but the others fail. Apparently they do I doubt that Deep Though handles this position much differently than most programs, what makes you think otherwise? >not recognize blacks strength. Despite the fact that bitboards were celebrated >for allowing that efficiently... >I find some high values astonishing. Is it really sound to estimate such high >evals? The evaluation function is full of similar heuristics, but of course some are more speculative than others. The main thing is that the heuristics are right more often than not. After that, everything becomes a speed/accuracy tradeoff where the balance of speed vs accuracy is according to the author's taste and ability. > >Oliver Roese
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