Author: Georg v. Zimmermann
Date: 10:48:54 09/13/02
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This is common. Search through the archives, you will find a lot of discussions about it. Especially if your extensions depend on the window. The simpler your search, the less this will happen. So if you disable all selectivity (null move, extensions, etc. ) and it still happens you might have a problem. Georg On September 13, 2002 at 12:06:18, James Swafford wrote: >[D] r1bq2rk/pp3pbp/2p1p1pQ/7P/3P4/2PB1N2/PP3PPR/2KR4 w - - > >You can see from the position above and the search output that this >is a simple mate. Somehow the program must see the mate during >iteration 2, hence the fail high at the root (it was searching with >a window of +/- 1 pawn of the previous score of 15). > >After the fail high, the search is restarted with a window of >15,+infinity, but Qxh7 doesn't do so well on the research (it gets >a -675), so it doesn't get backed to the pv, the rest of the moves >fail low, and I have to start a search in iteration three. > >I find it odd that the program could see Qxh7 was good enough to >fail high, but on the research failed low. How frustrating. :) > >Is this common, or do I have a bug? >-- >James > > >Problem 1: >r1bq2rk/pp3pbp/2p1p1pQ/7P/3P4/2PB1N2/PP3PPR/2KR4 w - - h6h7; > >parsing: h6h7...done. >correct move(s): h6h7 >FW Dpth Nd Cnt CSecs Score PV Line > 1& -> 15 0 -570 h6g7 g8g7 > 1& -> 216 0 10 h6g5 g6h5 > 1& -> 589 0 15 h6f4 d8e8 > 1 -> 2299 6 15 h6f4 d8e8 > 2& -> 3373 6 15 h6f4 d8f6 f4f6 > 2& -> 6558 11 +++ h6h7 > 2& -> 7149 11 --- > 2& -> 7150 11 15 h6f4 d8f6 > 2 -> 27746 39 15 h6f4 d8f6 > 3& -> 32509 44 20 h6f4 g6h5 f4f7 g7h6 > 3& -> 74189 94 +++ h6h7 > 3& -> 75366 99 59997 h6h7 h8h7 h5g6 > 3 -> 77892 99 59997 h6h7 h8h7 h5g6
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