Author: Tony Werten
Date: 00:57:54 04/24/01
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On April 23, 2001 at 11:12:55, Rafael Andrist wrote: >In my chessprog, I'm using an Alpha-Beta-Search with an infinite window. After >adding a hashtable, only half of the nodes need to be searched, but I get still >a branching factor around 9. The use of Iterative Deepening didn't change much. >So now my question is what can I do to improve the search? Should I try to >improve the move-sorting? Or is it necessary to use other pruning techniques >like Nullmove? The use of iterative deepening doesn't nescesairy help the BF. It's advantage is that you don't need to decide on forehand how deep you are going to search. If you decide to search 10 ply and you run out of time, without ID you have nothing, with ID you have the best move of ply 9. BF of 9 is a bit too high but not too much if you don't use nullmove. There are a couple a reasons why it could be this high: Are you using killermoves ?(you should, noncaptures only) Is your evaluation a bit intelligent ? (it should, at least material and passed pawns) Do you store bestmoves in the hashtable (you should) ? Do you store bestmove if score is <=alfa ? (you shouldn't) How do you orden capturemoves (to start with, use MVV/LVA, most valuable victim, least valuable attacker ) Have you tried history tables ? (should help at lower depths ) Have fun trying out, Tony > >Thanks > >Rafael B. Andrist
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