Author: Rafael Andrist
Date: 11:59:13 06/03/01
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On June 02, 2001 at 15:29:36, Tony Werten wrote: >On June 02, 2001 at 14:52:56, Rafael Andrist wrote: > >>I've implemented a Nullmove-heuristic in my alpha-beta-search (full window). But >>now the number of nodes in Q-search explodes. Before, the number of Q-nodes was >>approximately the double of the normal nodes. Now it's 10x or more. This causes >>the problem that I need the same time for the same search depth as before, but I >>get a less accurate result. >>Is maybe my Nullmove implementation incorrect or is this "normal" and should I >>use futility pruning or something similar to reduce my Q-Search? > >No, there is something wrong. You should get at least 1 ply deeper in the same >time. > >Did you reduce depth with 3 ? ( R=2 and the normal 1 reduction ) Or even 4 ? The total reduction of remaining depth is 3 (compared to 1 in a normal subtree search) >Did you check not to do nullmove if you have no more depth left ? If there is no more depth left (remaining depth - 3 <= 0) a nullmove is made and a qsearch applied. If I disabled this and do the nullmove-search only if there is a positive remaining depth after the reduction, then I have practically disabled the nullmove, because I let my program normally search 7 or 8 plies deep and don't nullmove near the root (starting at depth 3). > >cheers, > >Tony> Rafael B. Andrist
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