Author: Vincent Diepeveen
Date: 04:51:42 10/11/02
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On October 11, 2002 at 07:43:40, Uri Blass wrote: But he's an old idiot. He's still talking about computerchess, forgetting how bigtime the weakest chain has gone up last few years. In 1997 games were decided by programs blundering away material. All programs were very weak in endgame by then too, any random rook endgame i could win from any program in 1997. How things have changed there... Even theoretical you can proof that without nullmove and without 'junior' type of forward pruning you can't get 18 ply fullwidth at all. Knuth in fact proved a lot about that already. It's so easy. Only because this guy has 'professor' before his name doesn't mean that he can do something that theoretical is impossible. Apart from that the statements from the deep blue team are very clear in 1999 in the IEEE advances where they show a 12 ply search. The 12.2 average depth in their artificial intelligence thesis. Then last but not least. No one got 12 ply in those days. I only remember fritz3 which by very dubious means got like 11 ply. Basically some preprocessors did get 11 to 12 ply thereby forward pruning last few plies a lot. None of them had things like simple mobility in the leaf eval even. Now deep blue got in the past when it was deep thought with 500k nodes a second after 3 minutes sometimes a search depth of 8 ply. With 126MLN, from which like 95% was wasted to parallel search, they got 12.2 ply. I see that as a good achievement. And it makes sense to me! >On October 11, 2002 at 07:12:34, Vincent Diepeveen wrote: > >>On October 11, 2002 at 04:08:49, Uri Blass wrote: >> >>Isn't his article clear enough yet? > >Bob Hyatt still claims that it was 12 plies software and 6 plies hardware >so I prefer to hear an answer directly from Hsu. > >> >>reporting a 12.2 average search depth fullwidth. >>I guess you never searched with a decent program fullwidth >>with extensions. If you did, you would understand that >>getting 12.2 ply fullwidth with loads of extensions is already nearly >>impossible. Every extended line is searched to the full depth, >>no pruning happens! > >I agree that 12.2 plies with a lot of extensions and no pruning is impossible >for normal programs and also is impossible for deep blue in case that >there were real 6 more plies in the hardware. > >The only case when it may be possible is if the 6 more plies in the hardware are >real selective search and it means more pruning than null move with R=3 and in >this case the 6 plies in the hardware may be eqvivalent to only 2 plies in >software because of big probability to miss things. > >> >>The interesting 2 questions are >> a) did DB use 'no-progress pruning' in SOFTWARE (we know >> already it used it in hardware). > >They explained in the article that they did not want to take risks of missing >something in the first plies so it is clear that they did no pruning in the >first 12 plies. > >If they did some pruning in the software it is clearly after it. > >I do not know what is exactly no progress pruning. >Is there a difference between it and null move pruning? > >Is no progress pruning more aggresive than null move pruning? > >Uri
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