Author: Robert Hyatt
Date: 20:43:02 07/06/99
Go up one level in this thread
On July 06, 1999 at 17:15:44, blass uri wrote: > >On July 06, 1999 at 13:33:01, Robert Hyatt wrote: > >>On July 04, 1999 at 06:19:17, Frank Schneider wrote: >> >>>On July 03, 1999 at 19:16:59, Gerrit Reubold wrote: >>> >>>>Hi all, >>>> >>>>please test your programs with the following position >>>> >>>>5rk1/1r3pp1/pp2pq2/3p4/3Q4/1PR5/P4PPP/4R1K1 w - - >>>> >>>>it is from a game which my program (Bringer) lost with white against The Crazy >>>>Bishop. The draw is very easy to see (for humans): Qxf6 gxf6, and then rook >>>>checks at h3, g3, f3... How long does your program take to find Qxf6 *with a >>>>draw score*. How many plies / seconds? Question to the programmers: What do you >>>>do to solve such positions fast? Extending on checks is not enough, my program >>>>needs a 12 ply search (8 minutes on a PII-300) to find the draw (Qxf6 is found >>>>earlier). >>>Gromit shows a drawscore after iteration 5 (1sec). >>> >>>Frank >>>> >>>>Greetings, >>>>Gerrit Reubold >> >> >>This is an evaluation issue. If your program thinks white is better, then it >>will see a draw. If your program likes black, then it will find that black >>doesn't _have_ to take the draw as the repetition is certainly not forced if >>black or white doesn't want to repeat. > >The repetition is forced. >It is a perpetual check. >I agree that a program can see the draw for the wrong reasons but it does not >change the fact that white has perpetual check after Qxf6 gxf6. > >Uri Sorry.. reversed colors... if a program likes white in that position, it won't see a perp. Because white has the option and not black. Many of these positions revolve around that theme... because it isn't too uncommon to see a game where both sides think they are winning or think they are losing... This is a deep perpetual however, because the right path is to diagonally move the king up, and then using the other color squares, back down the board. Which pushes the draw _way_ off into the future. Crafty (quad xeon) sees this easily in tournament time controls, but at fast games, it doesn't have a chance. And I really don't mind, as there are some tactics I am willing to miss, to avoid the time wasted in other positions where such tactics don't work... 6 of one, half-dozen of the other...
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