Author: Stuart Cracraft
Date: 14:52:16 02/22/06
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On February 22, 2006 at 17:08:51, Matthias Gemuh wrote: >> >>At http://www.albert.nu/programs/sharper/perft.htm, the author >>says he has verified perft(up to 10) with a variety of engines as: >> >>Initial position rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 >>Depth Perft value >>1 20 >>2 400 >>3 8902 >>4 197281 >>5 4865609 >>6 119060324 >>7 3195901860 >>8 84998978956 >>9 2439530234167 >>10 69352859712417 >> >>So it is in disagreement for 3 with 9322. >> >>When I run my perft(up to 5), I get >> >>1 20 >>2 420 >>3 9322 >>4 206603 >>5 5072212 >> >>So now I am more confused. What's right? Who's wrong? >> >>--Stuart > > >Congratulations ! Your perfts are OK. > >Matthias. Thanks all. I ran them out to perft(6) in the opening position and it is okay (to 6 ply): .sd 6 maxdepth = 6 maxtime = 9999999 timed = 0 .perft perft(1) nodes visited = 20 perft(2) nodes visited = 400 perft(3) nodes visited = 8902 perft(4) nodes visited = 197281 perft(5) nodes visited = 4865609 perft(6) nodes visited = 119060324 . At the website http://www.albert.nu/programs/sharper/perft.htm the author says: Position r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - This position is very good because it catches many possible bugs. Depth Perft value 1 48 2 2039 3 97862 4 4085603 5 193690690 6 8031647685 So I tried it and got matching numbers as far as I went (5). This exercise has given me respect for what alpha-beta and refinements have done to minimax. Stuart
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