Author: Roberto Waldteufel
Date: 10:35:02 06/22/98
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Hi Guido, It seems I had misinterpreted Negascaout. Perhaps my misinterpretation even constitutes a new variant of this family of search algorithms. My metod on each iteration is as follows: At each node, I search the first move with window {alpha,beta): value=-Search(-beta,-alpha,depth-1) If value>alpha then If value>=beta then Search=value Exit End If Alpha=value End if Then, if I did not get a beta cut-off, for each subsequent move from that node I do a null width search, with a research if necessary,like this value=-Search(-alpha-1,-alpha,depth-1) If (value>alpha) and (value<beta) then value=Search(-value,beta,depth-1) End if If value>alpha then If value>=beta then Search=value Exit End If Alpha=value End if This was my interpretation (or misinterpretation) of Reinfeld's pseudo-code. To be more precise, I search to depth instead of depth-1 if the side to move is in check. Compared to classical alpha beta with infinite window, it was a great improvement. I'll have to look at Reinfeld's code again a bit more closely, but my method seems to work so well that I would need to be really convinced before recoding it all over again. Do you think I could improve my speed with a proper PVS? Maybe I waste a lot of time searching the first move to full width instead of with a null window. Best Wishes, Roberto
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