Author: Georg v. Zimmermann
Date: 04:55:26 06/17/02
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>1) We are pondering, do a deep 20 ply search and see that we have >a combination to promote a pawn or three. We start failing high >bigtime. > >2) The opponent plays a different move than expected, but because >this is an endgame, it transposes into the variation we were pondering >anyway, so we get a lot of hash hits. > >3) We start our normal search on ply 3 with a window [-50,50]. >We get a hash hit one of the bottom nodes. It indicates a lowerbound >of +2000. This is enough to get a cutoff, and we fail high. > >4) We restart our normal search on ply 3 with a window [50, inf]. >We get a hash hit one of the bottom nodes, but this time the bound >is _not_ enough to get a cutoff. We search this node, and (because >we're only 3 ply deep), only see an advantage of 0.01. We fail low. This shouldnt happen. When you get a hash hit that is deep enough and is a lowerbound above alpha you should set bestValue (assuming fail soft) = 2000 here. Then you never return 0.01 . Georg
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