Author: Uri Blass
Date: 06:25:24 06/04/02
Go up one level in this thread
On June 04, 2002 at 08:59:10, Vincent Diepeveen wrote: >On June 04, 2002 at 08:29:12, Uri Blass wrote: > >>On June 04, 2002 at 07:17:03, Vincent Diepeveen wrote: >> >>>On June 04, 2002 at 02:33:55, Russell Reagan wrote: >>> >>>I have been wasting a lot of time in search past years. >>> >>>Like last months i have wasted my time working on forward pruning. >>> >>>Sure i can search 3 ply deeper with it (and kicking out singular >>>extensions and other extensions). >>> >>>However if i do that, then it scores simply 20-25% worse in tests >>>against commercial programs. >>> >>>The reason was not so hard to find for me. It simply goes for 1 >>>move and stays with that move. The rest gets forward pruned. Chances >>>to find a superb move is way smaller. >> >>In this case it is a bad way of using forward pruning. >>The idea of forward pruning is to prune tactical blunders and not to prune >>positional moves. > >Fritz7 is doing opposite of pruning tactics. It seems to only prune positional >lines. Idem for junior. Junior only sees tactics deeper. It simply >gives for a simple rook move like Rab1 (if b-file isn't an >open file) 2 ply penalty (or better the move costs around 3 ply >to make). I do not think to try to do the same as Fritz and Junior. The first idea to save time is by pruning of tactical blunders and pruning of positional moves seems to be less simple but it does not mean that it is impossible. I also do not consider what Junior does as pruning(if your guess about it is correct). It can be described as not doing extensions in the case of 2 ply panelty and doing negative extensions in the case of 3 plies panelty. Pruning for me means simply to return evaluation without searching of legal moves of the opponent. Except null move pruning I do it only when the remaining depth is small(otherwise it is very risky). Uri
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