Author: Severi Salminen
Date: 00:37:38 01/06/01
Go up one level in this thread
>>My problem was to decide what to use as the best score if all the moves >>were pruned because off futility pruning, also in qsearch. In qsearch I decided >>to return alpha and nothing less. > >It ok to return the stand-pat score or alpha, depending on which is higher. >If you increase alpha to the stand-pat score in the beggining of your >qsearch it is ok to return alpha of course. This is what I do now. >>I don't know if it is right, but it worked. >>And in normal search I use material_balance + FUTILITY_MARGIN to alter the >>bestscore so far. I don't know whether I should include the material gain of a >>move or exclude the MARGIN, but now things work. Maybe you should check out >>those and experimant. > >I start from -inf and see if I can improve upon that, if not, I just >return -inf and let the previous level fail high. Whatever score we >find at a node with futility pruning is always a lower bound. It does >not matter for my question though because all futility pruning was >disabled. > >What do you mean by altering bestscore? Do you mean you increase alpha >to the values you mention? Well, my initial point is that should I ever return a lower value than alpha? I think that it could improve all researches (if necessary). So if all moves in node are futility pruned I have bestscore=-INF which is not correct. What is the value I have to return? Alpha is probably good, but I think if there is a better approximation it would help possible researches. Severi
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