Author: Joachim Rang
Date: 11:58:26 03/13/03
Go up one level in this thread
On March 13, 2003 at 14:41:12, Albert Bertilsson wrote: >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 OKING = opponent king, I see. This is an interesting idea, but I doubt that such a general bonus will improve playing strenght. there might be positions where the game is decided on the queenside and all pieces are needed there, than such a bonus may hurt. Have a look at the post, it's either way interesting, it's just to get own ideas
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