Author: Uri Blass
Date: 15:48:22 09/15/01
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On September 15, 2001 at 17:00:07, Vincent Diepeveen wrote: >On September 15, 2001 at 16:18:42, Uri Blass wrote: > >>On September 15, 2001 at 15:56:06, ALI MIRAFZALI wrote: >> >>>Although much has been said about moves like Be4 in game 2 of the second match >>>with Kasparov and h5 in game 5 of the second match because of the great >>>controversy that these moves have generated;the positions that happen >>>after these moves are not a good comparison test for seeing if current >>>commercial programs running on ordinary machines play at or beyond the level >>>of deep Blue.Let me first turn my attention to the first match game 5.At move >>>29 Deep blue plays29.g3? Kasparov says that after 29.Ne2 Rxe2 30.Qxe2 Qa1+ >>>31.Nc1 White may be able to hold but the chances are still in Black's favor. >>>Interestingly Fritz6 chooses 29.Ne2 in this position(under 3 minutes 450MHZ). >>>In the same game at move 12 Deep blue plays 12.Rae1 .This is the case of moving >>>the Wrong rook.In the same position Fritz6 plays Rfe1 instantly.There is no >>>doubt that these positions prove that chess Knowelgde is very important for >>>chess programs.Since the Hardware that the deep Blue program was running on >>>was more powerful than anything commercial programs are running on even today >> >>The position is easy for programs with the relevant chess knowledge >>but can be also solved by search for programs without chess knowedge. >> >>I remember from a post of the programmer of yace >>that yace could find 29.Ne2 after some hours by search when >>g3 failed low for kasparov's move. >> >>I believe that the search algorithm of Deep blue were simply >>inferior than the search algorithm of the chess programs of today >>(otherwise some hours of yace could be translated to some minutes >> of the chess programs of today) >>>;the question of the Camparison of a top commercial program like Fritz6 and >>>Deep blue comes down to this question:In a series of games will positions >>>that require chess knowledge for the selection of the best move occur more >>>often then positions requireing computational power? From the 2 matches with >>>Kasparov we can safely deduce that Deep Blue did not have much chess knowledge >>>in Camparison with Todays programs.Now let us see an example for Computational >>>Power.In the same game(game5 first match) at move 32 Deep Blue plays 32.f3 >>>Fritz6 (450Mhz) even after ruuning for 20 minuetes plays 32.gxf4 which is worse >>>than f3 because it leads to a faster loss. >> >>I remmeber that Genius3 on p100 could see f3 in a few hours. >>I believe that finding f3 may be dpendent in the >>evaluation function of the program and >>I expect part of the top programs on good hardware to find >>it in few minutes. >> >>Uri > >Please explain to me why f3 is better here than gxf4. I get direclty -2.xx >for gxf4 but after f3 you get an endgame which is so simplistically lost >that there is very little chance of ever even drawing it against a >strong player as you have a pawn less! > >I don't see why gxf4 would be worse as this involves heavy tactical dogfights >which all are real good for black, but the alternative is a technical >simplistically won position! > >Probably Deep Blue evaluated the endgame wrong after f3. Most likely >the border to play f3 nowadays is much tougher than back then. A lost >endgame shredder, diep and many programs evaluate as being -5.xx soon, >whereas old programs didn't come further than -1.x probably. > >In that case i bet nowadays commercials would directly play f3. > >Only objective search reveals of course at a certain time that gxf4 >is that bad, that the alternative, a dead lost endgame with a piece less, >where one can nullmove, is what you do. > >At 12 ply the score has dropped to 2.922 up for black for gxf4 still >f2-f3 not found here. But i bet that the same line which made DB decide >to play f3, that DIEP already saw that within a second here. > >We do not have the logfiles from deep blue here, so it is kind of useless >to say DB is tactical strong here. I bet it sucked so much everywhere >(compared to todays standards) that it took f3 within a second as >it probably saw > K+R+5 pawns versus K+R+B+3 pawns. So that's 3 for bishop - 2 for extra > pawns is 1 pawn down. Add a very small positional score in endgame > and it's 1.xx down for black there. > >Where diep says directly that f3 is over 3 pawns up for black. > >At 13 ply -2.857 for gxf4. > >Deep Blue simply sucked in endgame that it played f3, that's the >logical conclusion. Nothing else than that. You may be right. I said that it is a question of evaluation. I remember that Genius3 found f3 with evaluation of about 2 pawns against white. Uri
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