Author: Albert Bertilsson
Date: 11:41:12 03/13/03
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On March 13, 2003 at 14:35:15, Joachim Rang wrote: >On March 13, 2003 at 14:23:08, Albert Bertilsson wrote: > >>Hi! >> >>I've just taken a major step in my engine, adding more knowledge than material >>and pst. As I know little of chess I have very small knowledge of the points to >>give to each knowledge but the major problem is that things seem to get worse! >> >>When I run a 10 position benchmark I've noticed that the knowledge the more >>nodes have to be searched, and branching factor gets higher and higher, this was >>not what I expected, my guess was that with better knowledge the program would >>pick better lines earlier and get a lower branching factor. >> >>The basic implementation know have pst values ranging from 0 to 0.2 pawns, and >>the following defined bonuses: >> >>Pawn = 100 >> >>#define DOUBLED_PAWNS -30 >>#define PAWN_NOT_ISOLATED 10 >>#define BOTH_BISHOPS 25 //Added if both bishops are left >>#define ROOK_HALF_OPEN_RANK 20 >>#define PAWN_CLOSE_TO_KING 10 //Added for each pawn withing one square from king >>#define QUEEN_CLOSE_TO_OKING 20 >>#define KNIGHT_CLOSE_TO_OKING 10 >> >>I know this is just the beginning but I still expected to get better results, or >>is there a flaw in my thinking. >> >>/Regards Albert > >I know little about adding knowledge, but I think your values are generally too >high. In the following post on the message board of chessbrain you find all >default values for Beowulf described by Colin: > >http://www.chessbrain.net/bbs/viewtopic.php?t=145 > >For example, colind add only 4 centipawns for a rook on a half-open file. Your >last two values I don't understand. do you add a bonus for the knight or the >queen to be close to its own king? This seems strange for me. I give a bonus when the Queen or Knight is close to the opponent king (OKING), I'm not sure about doing this for the queen, since it travels long distances but I think it's good for the knight. So the values are to high? 4 seems very little, but perhaps the point is that it should not affekt scoring very much. I'll try lowering them much... I appreciate that you recomended the link, if I get very desperate I'll look at it, but I like to do things of my own. /Regards Albert
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