Author: blass uri
Date: 23:42:45 10/21/99
Go up one level in this thread
On October 21, 1999 at 20:22:44, Thorsten Czub wrote: >Example why it is dangerous to use a program >like Fritz6 in analysis for (e)mail-chess: > >In the moment i am playing a public game against >anonymous person in a newsgroup. > >during the analysis i came to the following situation: > >after the moves > >[Event "mail-chess-game"] >[Site "gambit-soft-board"] >[Date "1999.10.22"] >[Round "1"] >[White "Thorsten Czub"] >[Black "Anonymous called <Rudi>"] >[Result "*"] > >1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3 5. Qxf3 Qxd4 6. Be3 Qh4+ >7. g3 Qg4 8. O-O-O Qxf3 9. Nxf3 c6 10. Bg2 Nbd7 11. Rhe1 e6 12. Nd4 Bc5 >13. Na4 Bxd4 14. Bxd4 O-O 15. b3 Re8 16. Nb2 Nb6 17. Nd3 Nfd5 18. c4 Nf6 >19. Bf3 Nfd7 20. Nf4 Kf8 21. Bb2 a5 22. Ba3+ Kg8 23. c5 a4 * > > > >the following position came on board of fritz6: > >Ich - Rudi >r1b1r1k1/1p1n1ppp/1np1p3/2P5/p4N2/BP3BP1/P6P/2KRR3 w - - 0 1 > >fritz6 evaluated the position and the chances as follows: > > >Analysis by Fritz 6: > >24.Txd7 > -+ (-2.97) Tiefe: 1/3 00:00:00 >24.Txd7 Sxd7 > -+ (-3.31) Tiefe: 1/4 00:00:00 >24.cxb6 > = (0.16) Tiefe: 1/4 00:00:00 >24.cxb6 Sxb6 > = (0.16) Tiefe: 2/4 00:00:00 >24.cxb6 > = (0.00) Tiefe: 3/5 00:00:00 >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > µ (-1.22) Tiefe: 3/9 00:00:00 >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > µ (-1.22) Tiefe: 4/6 00:00:00 >24.cxb6 axb3 25.Kb2 bxa2 26.h3 > µ (-1.12) Tiefe: 5/13 00:00:00 1kN >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.h3 > µ (-1.06) Tiefe: 6/16 00:00:00 7kN >24.cxb6-- > µ (-1.37) Tiefe: 7/11 00:00:00 8kN >24.cxb6 > µ (-1.37) Tiefe: 7/15 00:00:00 10kN >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.h3 e5 28.Td6 > -+ (-1.56) Tiefe: 8/16 00:00:00 20kN >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 e5 28.Lc5 Sd7 > -+ (-1.66) Tiefe: 9/17 00:00:00 43kN >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Te4 e5 28.Tde1 f6 > -+ (-1.69) Tiefe: 10/20 00:00:00 158kN >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Te4 e5 28.Tde1 f6 > -+ (-1.72) Tiefe: 11/26 00:00:01 506kN >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 e5 28.Lb2 f6 > -+ (-1.78) Tiefe: 12/27 00:00:06 1909kN >24.cxb6 axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 e5 28.Lb2 f6 > -+ (-1.81) Tiefe: 13/31 00:00:30 10018kN >24.b4 > -+ (-1.78) Tiefe: 13/31 00:01:02 20891kN >24.b4 Sc4 25.Lb2 Sxb2 26.Kxb2 e5 27.Sd3 f5 28.Lh5 Te7 > -+ (-1.69) Tiefe: 13/33 00:01:29 30248kN >24.b4 Sc4 25.Lb2 e5 26.La1 Sf6 27.Sd3 Le6 28.Sxe5 Sxe5 > -+ (-1.59) Tiefe: 14/31 00:04:11 84912kN > >As you can see from the analysis above, fritz6 thinks >it is 1.5 pawns up. >A few main-lines before it came to the conclusion that >cxb6 axb3 etc. is worth only 1.81 so it changes to >b4 because it thinks this would be a better idea for >white. > >Now we make 24.cxb6 and watch out what fritz6 says now : > >Ich - Rudi >r1b1r1k1/1p1n1ppp/1Pp1p3/8/p4N2/BP3BP1/P6P/2KRR3 b - - 0 1 > >Analysis by Fritz 6: > >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > = (0.09) Tiefe: 4/10 00:00:00 1kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > = (0.09) Tiefe: 4/10 00:00:00 1kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > = (0.09) Tiefe: 4/10 00:00:00 1kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > = (0.09) Tiefe: 4/10 00:00:00 1kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > = (0.09) Tiefe: 4/10 00:00:00 1kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > = (0.09) Tiefe: 4/10 00:00:00 1kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 > = (0.09) Tiefe: 4/10 00:00:00 1kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 > ² (0.28) Tiefe: 5/14 00:00:00 7kN >24...axb3 > = (-0.03) Tiefe: 6/14 00:00:00 20kN >24...axb3-- > ² (0.28) Tiefe: 7/16 00:00:00 49kN >24...axb3 > ² (0.28) Tiefe: 7/19 00:00:00 75kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 Sd7 28.Le4 e5 > = (0.09) Tiefe: 8/22 00:00:01 322kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 e5 28.Ld6 g5 29.Sd3 > = (0.00) Tiefe: 9/21 00:00:02 848kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 e5 28.Ld6 g5 29.Sd3 > = (-0.03) Tiefe: 10/24 00:00:08 2685kN >24...axb3 25.Kb2 bxa2 26.Kxa2 e5 27.Kb3 f6 28.h3 Kf7 29.Sd3 > = (-0.09) Tiefe: 11/28 00:00:33 9872kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 e5 > = (-0.22) Tiefe: 12/29 00:02:01 37126kN >24...axb3 25.Kb2 bxa2 26.Kxa2 Sxb6 27.Kb3 e5 28.Ld6 f6 29.Lh5 > = (-0.19) Tiefe: 13/31 00:08:23 151133kN > > > >HOW can this be ? > >I guess it loads new piece-square-tables (preprocessing) >with new values and gets a totally different >impression from the position than ONE PLY before. > >it is obvious that this way the whole main-line >computation of ONE PLY BEFORE was senseless time-wasting, >since the new thought-computation gets a different >point of view about the position. > >Guess you are a newbie in computerchess, guess >you don't know about chess programs and guess you >have bought this very strong program, the package >says it got 2800 ELO performance against top-players. > >you trust this. >and you analyse your games with it. >you know that the longer you let fritz6 compute, >the better the results will be. > >you have to consider about the position. >and you get the one or the other evaluation from fritz6: > >one time it says black is 1.5 pawns ahead, >and ONE ply later it says : oh - not a problem, only 1/5 >of a pawn against white. > >So - many years we had genius having asymmetrically evaluations >and main-lines. >It had the same effect: you let it compute >a long time about a position, it says 1.5 for black (e.g.) >and you give it ONE PLY later and it says only 0.2 for >black. > >This time Fritz6 replaces the Genius misbehaviour: >i don't think it has an asymmetrical search, but i guess >the preprocessing makes it reevaluate only the root- >positions, without making sensible changes in the main-line. >cxb6 was in the main-line of the 24th move. >but this move was not moved on the board. >One ply later the root position is another, fritz has to load >new values in the tables, and suddenly the whole score changes >1.3 pawns ? > >How can a chess-program come to sensible information with >this type of behaviour ?? >How can you trust the analysis of a chess program >when it changes its mind this heavily ? >How can you create a sensefull main-line when >ONLY the root position gets somehow evaluated, and >not the moves in the main-line far from the 1st ply ? > > > >(BTW: fritz5.32 behaves the same way. it works the >same way, using heavy preprocessing methods.) > >Fritz5 and Fritz6 are strong programs. >When you let them play against humans or against >other chess programs. They are not the strongest >chess programs (ChessTiger and others are much stronger) >but they are much for the money they cost. > >But - as an analysis tool for chess players... >NO ! > > >i would like to see all my opponents use this type of programs >(nimzo, junior...) >so that i can easily beat them. Junior is not a root processor. It is a processor of something(not fixed) that is more down in the tree. It may change its mind after a move because of some bugs(For example I found that there is a position that it cannot see a simple stalemate combination plays the wrong move and say mate against itself) but these bugs are rare in practical games. Uri
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