Author: Uri Blass
Date: 12:47:24 09/06/02
Go up one level in this thread
On September 06, 2002 at 14:42:02, Robert Hyatt wrote: >On September 06, 2002 at 13:33:29, Vincent Diepeveen wrote: > >>On September 05, 2002 at 14:06:08, Eugene Nalimov wrote: >> >>>Actually, often you don't want to search the objectively best move first. You >>>want to search the move that will cause a beta cutoff and will result in a >>>smallest subtree being searched. >> >>Not really, the best move is usually best, because usually the >>problem of *a move* cutting off is shown next iteration by major >>overhead. So at this iteration i a move could cutoff in very little >>nodes, but if it next iteration fails low it obviously is a whole >>subtree you researched. > > >Would you _please_ think a bit before jumping in? Eugene's statement is a >direct premise of any tree searching program based on alpha/beta. Do the >least amount of work possible. Given a set of N moves that will produce a >cutoff (fail high) and another set M that will not... If you search any moves >in M first, you waste time and effort and slow down. If you search any move in >N you get a cutoff and are done. How can it _not_ be best to pick the one that >requires the least effort to fail high? Because once you fail high at a node, >you are _finished_ there.. If this iteration is the last iteration you are right. The point is that if the iteration is not the last iteration you may prefer to have a move with bigger tree if it means that the tree for the same position is smaller in later iterations. I do not know if the best move is usually best and I guess that things are also dependent in your pruning and extensions rules. You can also consider moves that force repetition as best if you get a cut off by 1 node thanks to them. Uri
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