Author: Uri Blass
Date: 05:25:16 07/25/03
Go up one level in this thread
On July 25, 2003 at 06:17:57, Tord Romstad wrote: >On July 24, 2003 at 14:52:34, Matthias Gemuh wrote: > >>On July 24, 2003 at 10:35:46, Tord Romstad wrote: >> >>>>> >>>> >>>>BigLion ? no checks in QSearch(). >>> >>>OK, this confirms my suspicion that checks in qsearch have a great influence >>>on the solution time at this position. >>> >>>Have you tried searching checks in qsearch? It is worth a try, IMHO. It >>>seems that different people have very different experiences with this, but my >>>program plays much worse in the middle game when I remove the checks. In >>>the endgame it is less clear; I am currently experimenting with this. >>> >>>Tord >> >> >> >>BigLion is very slow, so checks in QSearch() almost halt the engine :). > >Gothmog is also not among the fastest. It does around 150-200KNps on a >Pentium 4 2.4GHz. > >I am not sure checks in QSearch is necessarily a bad idea in slow engines. >Many of the old, slow dedicated chess computers in the late 80s and early 90s >had checks in QSearch(), I think. Checks in QSearch() do not have to be >very expensive, if you put severe restrictions on what checks you include. >This is how I do it: > >In the QSearch(), I first generate and search all non-losing capture moves. >If none of the capturing moves resulted in a cutoff, I generate and search >non-capturing checks if both of the following are true: > >1. We are at the first ply in QSearch(), or all previous moves in QSearch() > for the side to move have been checks and all moves from the opponent have > been single-reply-to-checks. > >2. alpha < KNIGHT_VALUE. > >At least in my program, this works very well and is not particularly >expensive. > >But as BigLion is apparently slightly stronger than Gothmog at the moment, >I am probably not the best person to give you advice. :-) Why do you think that Biglion is stronger than Gothmog? Based on the information that I read it seems that Gothmog is clearly better than Biglion. Uri
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