Author: José de Jesús García Ruvalcaba
Date: 10:14:13 08/05/99
Go up one level in this thread
On August 04, 1999 at 19:03:25, Pete R. wrote: >On August 04, 1999 at 14:57:02, José de Jesús García Ruvalcaba wrote: > >>On August 03, 1999 at 21:29:14, Pete R. wrote: >> >>>Currently in the Kasparov vs. The World correspondence game there are a number >>>of endgames that involve races between passed pawns on either side of the board. >>>While the programs have been quite useful so far, they aren't too swift in the >>>transition to the endgame when passed pawns are the issue. Where a human player >>>would push his passed pawn at every opportunity, the programs tend to diddle >>>around moving pieces, until the pawn is almost promoted, when they suddenly >>>realize that one side is winning. For example in the following position, >>> >>>8/1p1kp2Q/2np4/1p2bpB1/8/3q3P/5PP1/5RK1 w - - >>> >>>I ran Fritz 5.32, Hiarcs 7.32, and Crafty 16.12 for many hours, enough to get to >>>18 ply for Fritz and Crafty. All of them recommend the move g4 for white >>>(Crafty switches to g4 at 15+ ply), which gets buried by b4!. For example, >>> >>>27. g4 b4 >>>28. Qxf5 Qxf5 >>>29. gxf5 b3 >>>30. Rb1 b2 >>>31. Kf1 Na5 >>> >>>and by now they will realize that white is losing. There are a number of >>>possible endgames coming up involving a race between white's passed h pawn and >>>black's passed b pawn, and the programs have a real hard time with it. What's >>>going on here? >> >> I recommend to use crafty 16.15 with 'extension pushpp 1.0' for this and >>similar positions, it will extend more aggresively on passed pawn advances (the >>default is 0.75), and will see the dangers at shallowers depths. >> I can not do it myself because I do not have "many" hours of computer time >>available. >>José. > >Thanks, I'll play with these new parameters. I think the ppscale might be the >one to use vs. the extension, but I'll have to fiddle with it. Yes, increasing 'evaluation ppscale' can also help. Values over 200 are not recommended (the default is 100). I love these features of crafty.
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