Author: Uri Blass
Date: 16:43:08 08/31/04
Go up one level in this thread
On August 31, 2004 at 19:25:39, Stuart Cracraft wrote: >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. Note that I use verified null move pruning only in the endgame and in the middlegame I use null move pruning with no verification. I did not test a lot of possibilities there and I only know that R=3 is significantly better than R=2 and I also read that people who do checks in the qsearch tend to prefer R=3(you do not do checks in the qsearch and I mean not to replies to check). > >Who or what is Leonid? > >Stuart Leonid posted in this forum mate problems Uri
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