Author: Sune Fischer
Date: 00:00:46 11/05/02
Go up one level in this thread
On November 05, 2002 at 02:49:12, Gerd Isenberg wrote: >On November 04, 2002 at 19:03:21, Sune Fischer wrote: > >>On November 04, 2002 at 18:46:50, Gerd Isenberg wrote: >> >>>On November 04, 2002 at 18:11:59, Sune Fischer wrote: >>> >>>>On November 04, 2002 at 16:55:10, Uri Blass wrote: >>>>> >>>>>Depth 11 was finished few minutes ago and the score is very convincing. >>>>>It seems that depth 11 is good not only to find the fail low but also to find >>>>>the fail high for Be6 >>>>> >>>>>11 67 161361 228198851 c8e6 >>>>>11 319 201885 285759097 c8e6 f4c1 c3c2 b1b2 e6c4 b2a3 c7c5 a3b2 c2d1n g1d1 b4d3 >>>>>d1d3 c4d3 d4c5 d6c5 c1c5 d8b8 b2c3 d3e4 >>>>> >>>>>depth=11 +3.19 c8e6 f4c1 c3c2 b1b2 e6c4 b2a3 c7c5 a3b2 c2d1n g1d1 b4d3 d1d3 c4d3 >>>>>d4c5 d6c5 c1c5 d8b8 b2c3 d3e4 >>>>>Nodes: 285759097 NPS: 141545 >>>>>Time: 00:33:38.85 >>>>> >>>>>Uri >>>> >>>>Congrats, I knew Movei could do it though :) >>>>Your PV is 19 plies, so a bit extended. >>>>Looks like there is a knight promotion, I wonder how often these underpromotions >>>>aren't fail lows, cause I'm thinking of removing them completely, better branch >>>>factor and all you know... >>>>Of couse I would keep them at the root, so as not to have a bug, what do you >>>>think? >>>> >>>>-S. >>> >>>Carefull - at least the knight promotion should be considered. But if the >>>queen-promotion is rejected by capture of the promoted queen, underpromotions >>>make not much sense, because they may captured as well. If a queen promotion >>>forces a stalemate-draw, also rook as well as bishop promotions should be >>>considered. >> >>Well yes there is a risk, but how often does it happen? >>I think searching underpromotions is basicly a waste of time, if the queen >>promotion isn't good enough, then most likely the others can be discarded as >>well. Bishop promotions must be very rare, I don't recall ever having seen a PV >>with a bishop promotion, 99 of 100 it's a queen. >> > >Ok, but with conditional move generation of the underpromotions triggerd by undo >queen promotion the risk of missing one move is zero. And in most of the cases >no additional underpromotions are generated. > >Gerd Yes, in this case there is no win, only when the position fails low do you save some searching. May be it is better to simply de-extend them a bit, and not to generate them at all in qsearch. -S.
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