Author: Steve Maughan
Date: 06:37:00 04/06/05
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Johannes, I believe W-Chess does some thing similar. The drawback is that after a relatively complex exchange (e.g. exchanging pawns around the king) there may be significant changes in positional factors (e.g. king safety), which will result in inaccurate values going up the tree. IMO it's too risk. Regards, Steve >Hello! >Right now im working on a new Version of my Chess Engine and an idea has come to >my mind, but i dont know if its applicable: >When I'm in Q-Search i only want to deal with material values. I handle theses >incrementally, so theres is no need for any function call except the Q-search >recursion. >After returning from Q-Search (at the full-width horizon) i simply add the >positional eval score to the score returned from Q-search. This score is >returned "up the tree". >For the positions before the horizon this should be no problem concerning >alpha/beta values etc... . Also positions beyond the horizon should not suffer >from this, as long as the alpha/beta values were not passed to a Node before the >horizon before. If they were, the alpha/beta bounds would not be correct, >because they include positional scores which are not considered beyond the >horizon. >So my idea is to simply substract the local positional score from the alpha/beta >values (as long as they are not -INF or +INF) at the full-width horizon, before >entering Q-Search. I assume that this would result in correct cutoffs. >Is this idea correct? >I didnt find any drawbacks yet, but i only have a vague intuition about it. >I really would appreciate if anybody could help me with this. >greets >johannes
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