Author: Robert Hyatt
Date: 08:09:32 05/13/04
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On May 13, 2004 at 03:35:00, Daniel Shawul wrote: >Hello > >My search is fail soft(i return the actual score) >when i fail high at the root i widen the window by 3 pawns (300). > > if(score<=r_alpha) > { > r_beta=r_alpha; > r_alpha=score-300; //r_alpha = -MATESCORE; > } > else if(score>=r_beta) > { > r_alpha=r_beta; > r_beta=score + 300; //r_beta = MATESCORE; > } >If the search fail's high at 1.75 score but the real score was 10 >i get a score of 4.75 (1.75 + 3) in the next iteration. Why? my search is fail >soft and the score returned should be independent of beta. If i change the 200 >to 300,score returned is 4.75?? There is much more to fail-soft that just returning a score outside the bound window. Normally at the front of search, your alpha value is passed in and even if a search call returns a value < alpha, you still maintain alpha as the "best" value. That is not fail-soft..
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