Author: Oliver Roese
Date: 21:45:37 06/09/00
Go up one level in this thread
On June 09, 2000 at 23:36:17, Peter McKenzie wrote: >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? > You are right. It should have read "DarkThought WCCC'99". See above. >>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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