Author: Uri Blass
Date: 08:18:31 10/12/03
Go up one level in this thread
On October 12, 2003 at 10:41:15, Omid David Tabibi wrote: >On October 12, 2003 at 10:01:39, Uri Blass wrote: > >>On October 12, 2003 at 09:47:39, Uri Blass wrote: >> >>>On October 12, 2003 at 09:27:09, Tord Romstad wrote: >>> >>>>On October 12, 2003 at 06:32:25, Omid David Tabibi wrote: >>>> >>>>>Recently I conducted some extensive experiments with two versions of Falcon, one >>>>>with checks in quiescence and one without. Falcon already has lots of >>>>>extensions, but adding checks in quiescence resulted in a significant boost for >>>>>tactical strength. >>>>> >>>>>I tested the following options: >>>>> >>>>>a) checks everywhere in quiescence >>>>>b) checks only in the first ply of quiescence >>>>>c) no checks in quiescence >>>>> >>>>>Option 'a' was ruled out after some testing, as it resulted in a total explosion >>>>>of quiescence search. I tried controlling it in some ways, but still the >>>>>overhead was considerably more than the benefit. It seems that The King and >>>>>HIARCS are the only engines using this method. >>>> >>>>These are not the only ones. I am fairly sure Diep searches checks everywhere >>>>in the >>>>qsearch, and Gothmog (my engine) also does. >>> >>> >>>If you searches checks every where in the search then by definition >>>you find the draw at ply 1 if your program has stalemate detection in its >>>evaluation. >>> >>>[D]r7/8/8/8/8/PPPP4/2QP4/k6K b - - 0 1 >>> >>>If it does not detect the draw at depth 1 even with checks everywhere then we >>>have different definition of everywhere so you should expalin your definition of >>>everywhere. >>> >>>extending escape to checks everywhere is not enough to search checks everywhere >>>and you need also to generate all possible checks everywhere. > >Of course. By checks in quiescence I mean all checking moves and check evasions. > >In the normal version I have neighter checking moves nor check evasions. > > >> >>or at least everywhere when the score is not above beta so you cannot return >>beta without generating checks and captures. >> >>Maybe this was not a good example but imagine a case when you sacrifice a piece >>to force perpetual check. > >You mean something like LCTII pos. 9: > >[D]6k1/5p2/3P2p1/7n/3QPP2/7q/r2N3P/6RK b - - 0 1 > >Even with checks only at the first ply of quiescence Falcon finds 1...Rxd2 in >less than one second. HIARCS which conducts checks everywhere in quiescence >finds this at the first iteration. I do not have latest hiarcs old Hiarcs finds it very fast but at depth 5 It is certainly faster than movei that finds it only at depth 7 after almost 2 seconds. New game 6k1/5p2/3P2p1/7n/3QPP2/7q/r2N3P/6RK b - - 0 1 Analysis by Hiarcs 7.32: 1...Qd7 2.e5 Qc6+ 3.Rg2 +- (2.37) Depth: 1 00:00:00 1...Qd7 2.Qd5 +- (2.57) Depth: 2/10 00:00:00 1...Qd7 2.Qd5 +- (2.82) Depth: 3/13 00:00:00 1...Qd7 2.Qd5 +- (2.82) Depth: 3/13 00:00:00 1...Nxf4 2.d7 Ne6 3.d8Q+ Nxd8 4.Qxd8+ Kh7 +- (2.65) Depth: 3/14 00:00:00 1...Nxf4 2.d7 Ne6 3.d8Q+ Nxd8 4.Qxd8+ Kh7 +- (2.65) Depth: 4/17 00:00:00 1...Nxf4 2.d7 +- (2.90) Depth: 5/19 00:00:00 14kN 1...Nxf4 2.d7 Ne6 3.d8Q+ Nxd8 4.Qxd8+ Kg7 5.Qd4+ +- (2.91) Depth: 5/21 00:00:00 23kN 1...Rxd2 2.Qxd2 +- (2.30) Depth: 5/21 00:00:00 34kN 1...Rxd2 2.Qxd2 Qf3+ 3.Rg2 Qf1+ 4.Rg1 Qf3+ = (0.00) Depth: 5/21 00:00:00 47kN 1...Rxd2 2.Qxd2 Qf3+ 3.Rg2 Qf1+ 4.Rg1 Qf3+ = (0.00) Depth: 6/21 00:00:00 58kN 1...Rxd2 2.Qxd2 Qf3+ 3.Rg2 Qf1+ 4.Rg1 Qf3+ = (0.00) Depth: 7/23 00:00:01 82kN 1...Rxd2 2.Qxd2 Qf3+ 3.Rg2 Qf1+ 4.Rg1 Qf3+ = (0.00) Depth: 8/25 00:00:01 159kN (Blass, Tel-Aviv 12.10.2003) Uri
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