Author: Dann Corbit
Date: 11:27:47 01/11/02
Go up one level in this thread
On January 11, 2002 at 13:00:46, Miguel A. Ballicora wrote: >On January 11, 2002 at 12:47:29, David Rasmussen wrote: > >>On January 11, 2002 at 12:40:03, Matthias Gemuh wrote: >> >>>On January 11, 2002 at 11:44:39, David Rasmussen wrote: >>> >>>>[D]2Q2n2/2R4p/1p1qpp1k/8/3P3P/3B2P1/5PK1/r7 w - - 0 1 >>>> >>>>In the above position, my search tree explodes because of extensions. It takes > >>>>3 minutes and 42 million nodes to finish an 8 ply search. How does your program >>>>do? >>>> >>>>Any good ideas on how to limit extensions in such a position. >>>> >>>>P.S. Solving the position is no problem. It is a simple mate in 5 plies, and is >>>>found very early on at depth 1 or 2 or so. Still, there must be something >>>>unsound about my extensions, or at least room for improvement, when this >>>>position makes the tree explode. >>>> >>>>/David >>> >>> >>> >>> >>>My HyLogicChess has the following stats: >>>All extensions active. >>>Quiescence moves: 29% (no explosion, my average is normally have 40%) >>>Total moves searched: 11000 >>>Speed; 84 kN/s >>>Move Ordering: 78% (normally 90%..92%) >>>[1] (0.18) 1.f3 (00h:00m:00s) >>>[2] (0.12) 1.Qb7 e5 (00h:00m:00s) >>>[3] (14.50) 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qxd6 (00h:00m:00s) >>>[4] (+Mate in 3) 1.Qxf8 Kh5 2.Rxh7 Kg4 3.f3 (00h:00m:00s) >> >>My program performs similarly if only searching to ply 4, but try letting it >>search to ply 9, even though it has already found the mate. That is what I am >>talking about. >> >>/David > >Gaviota's output: > >setboard 2Q2n2/2R4p/1p1qpp1k/8/3P3P/3B2P1/5PK1/r7 w - - 0 1 >d >+-----------------+ >| . . Q . . n . . | >| . . R . . . . x | >| . x . q x x . k | >| . . . . . . . . | >| . . . o . . . o | >| . . . B . . o . | >| . . . . . o K . | >| r . . . . . . . | >+-----------------+ > >sd 9 >go > 104 1: 0.0 +30.78 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8xd6 > 392 2: 0.0 +30.78 Qc8xf8 Kh6-h5 Rc7xh7 <EMPTY> > <-transp > 455 3 0.0 :-) Qc8xf8 > 530 3 0.0 :-) Qc8xf8 > 565 3 0.0 :-) Qc8xf8 > 1637 3 0.0 :-) Qc8xf8 > 3104 3: 0.0 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 4023 4 0.1 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 4475 4: 0.1 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 5444 5 0.1 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 8853 5: 0.1 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 11891 6 0.1 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 18148 6: 0.2 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 24692 7 0.2 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 48189 7: 0.4 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 62166 8 0.6 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 152926 8: 1.5 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 172449 9 1.6 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > 262305 9: 2.3 +Mat_3 Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 > Qf8-g8 > >Ply: 9 >Qc8xf8 Kh6-h5 Rc7xh7 Kh5-g4 Qf8-g8 >Score: 125.37 (32094) Evals: 90689 Time: 2.3s nps: 115400 Q/all: 0.36 > nodes cutoffs missed tree_exp >path 168830 26576 823 1.03 >quies 93475 31592 1083 1.03 >all 262305 58168 1906 1.03 >hashtable= attempts: 284553 hits: 35.3% perfect: 23.2% >move c8f8 For a mate in 3, it does not make any sense to search past ply 5 if you already see it. After all, when you have searched ply 5 and have a mate in 3, you cannot possibly improve it.
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