Author: José Carlos
Date: 01:25:40 01/16/04
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On January 15, 2004 at 06:26:47, Tord Romstad wrote: >On January 14, 2004 at 20:11:53, Dann Corbit wrote: > >>On January 14, 2004 at 16:49:29, Tord Romstad wrote: >> >>>Another simple trick is to reduce the resolution of your evaluation >>>function. In my pre-MTD(f) days, I used pawn=128. I still use pawn=128 >>>as the internal unit in my evaluation function, but before returning >>>the final score I divide the score by 2. This simple change made my >>>search noticably more efficient. >> >>Did you try other divisors besides 2? > >No, not yet. When I have cleaned up my source code a bit, I plan to make >it possible to choose the divisor in my init file. I don't think bigger >divisors would result in stronger play, though. It would make the engine >faster, but I am afraid a lower resolution would hurt the already poor >positional knowledge of Gothmog. > >Tord After some thought about this I came to the conclusion that the accuracy of the centipawn is less important when the eval is very big (positive or negative), so now I do something like: if (abs(eval) >= 30) { if (abs(eval) >= 150) eval -= (eval % 5); else eval -= (eval % 3); } I don't have my source here, but that's the idea. I even thought of using an array to slowly increase the divisor, but I don't think it's worth it to include a memory reference here. The 1 / 3 / 5 scheme works fine for Averno now. José C.
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