Author: Vincent Diepeveen
Date: 06:39:18 06/04/02
Go up one level in this thread
On June 04, 2002 at 09:25:24, Uri Blass wrote: >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. Well fact is that positional lines at depth=19 units sometimes only seem to get searched 6 ply sometimes by junior. That's the biggest positional pruning any program is doing. Most likely searching positoinal deeper doesn't bring them more because they are based upon piece square tables. >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). That doesn't prune enough to get a bunch of plies deeper though. What fritz is doing is getting it 3 ply deeper or so and what junior is doing is getting it 5 ply deeper or so. >Uri
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