Author: Stuart Cracraft
Date: 16:25:39 08/31/04
Go up one level in this thread
On August 30, 2004 at 15:53:13, Uri Blass wrote: >On August 30, 2004 at 15:34:22, Stuart Cracraft wrote: > >>On August 30, 2004 at 12:21:01, Uri Blass wrote: >> >>>On August 30, 2004 at 07:36:45, Volker Böhm wrote: >>> >>>>Hi Uri, >>>> >>>>do you allways check all evades in qsearch or only until a certain ply as for >>>>checking moves? >>>> >>>>Greetings Volker >>> >>>only until a certain ply but that ply is late. >>>I also do not check all captures and do it only until a certain ply. >>> >>>I practically have 2 functions of qsearch >>>int Quies(int alpha, int beta,int depth) >>> >>>int quiesmall(int alpha,int beta,int depth) >>> >>>Quies search checks and captures and when the depth is small enough Quies calls >>>quiesmall (quiesmall does not make checking moves that are not captures but it >>>calculate all replies to check unless the remaining depth is small enough and >>>when the remaining depth is 0 even captures are not tried. >>> >>> >>>Quies usually starts with depth=7 when depth=5 I call quiesmall and when >>>depth<=2 I do not generate replies to check and when depth=0 I do not make more >>>captures and retrun static evaluation+pawn with the idea that the side to move >>>may earn something by a capture but I do not know how much. >>> >>>It may be better to use static exchange evaluator but it is not very important >>>and most qsearch do not get to the place when depth=0 or the result of the >>>evaluation when depth=0 is not important for the final score. >>> >>> >>>Uri >> >>So for all the trouble you have gone to to do all of the above, can you >>point at specific measurable achievements you have gained from it? >> >>Stuart > >I know that checks in the first plies of the qsearch improved the strength of >movei(the improvement was obvious in test suites and I believe that it also >helped in games but I did not play enough games to test it) > >I remember that a buggy implementation that could return wrong mate scores did >not change much the strength in games and I later fixed bugs. > >I think that the main improvement was that after adding checks in the qsearch I >changed null move with R=2 to null move with R=3 and R=3 was obviously better >with checks in the qsearch(I did not check without them but I read or got the >impression that other programs found that R=3 is better with checks in the >qsearch when R=2 or E=2/3 is better without them). > >limiting the qsearch was always part of movei because I did not want the search >to explode in Leonid'a positions when both sides have many queens. > >Movei has problems to go deep in Leonid's position but it has no problem of >needing an hour to find mate in 1 that happened to Fritz in one similiar >position that was discussed here(Leonid usually gave harder problems than mate >in 1). > >Uri > >Uri Uri, For short searches of 1 second on my box, I've found adaptive null move with varying R to give better results than verified null move with R=3. Who or what is Leonid? Stuart
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