Author: Uri Blass
Date: 05:02:57 04/30/04
Go up one level in this thread
On April 30, 2004 at 07:49:10, Vincent Diepeveen wrote: >On April 29, 2004 at 09:28:53, Ed Schröder wrote: > >>On April 29, 2004 at 07:37:23, Vincent Diepeveen wrote: >> >>[ snips ] >> >>>>This is all very poor Vince, I assume you don't play much with nowadays top >>>>programs. From 1982 to 2001 Rebel won its games by positional understanding and >>>>not by search and Rebel lost its games because it was outsearched. Today Rebel >>>>isn't outsearched at all, it now loses its games because the current top >>>>programs have a better positional understanding than Rebel. >>>> >>>>You should have a good look at the current tops, the positional progress has >>>>been great the last years. To me it all seems to indicate (provided your search >>>>is okay) the only way to make progress is to improve on chess knowledge. But >>>>what's new, I already came to that conclusion in 1986 after some intensive talks >>>>with Hans Berliner. >> >>>What i mean is Ed, is that you would not have accomplished the great results >>>with Rebel which you managed, had you just searched with a fullwidth search + >>>bunch of checks in qsearch. >> >>No of course not, brute force is silly, Rebel since day 1 has been a selective >>program. But I am getting your point, in the days before the nullmove was >>discovered Genius and Rebel had the best (static) selective search, a dominant >>factor in their successes, is that what you meant to say? If so, it is true. > >That's what i mean, using a simple form of search in those days meant fullwidth. > >>If only Frans had kept his mouth shut to Chrilly (Chrilly leaking nullmove in >>the ICCA journal) it is very likely Fritz would been the next Richard Lang still >>dominating all the rating lists and WCC's for the last decade. But Frans didn't >>and then all bets were off. > >Frans' world title in 1995 had a huge positive impact. > >> >>>I am under the impression that you just like diep try checks at several depths >>>in the qsearch. In diep i can try at the entire 32 ply of the qsearch checks. >> >>Checks in QS are relative cheap nevertheless I have limited them more and more >>the last years. There is little sense doing long range QS checks if you already >>hit 12-14 plies. > >I see that different, but i must add the note that Rebel is basically tactical >selective in main search already and DIEP isn't. I do very little extensions in >diep other than singular. Even check hardly gets extended, i'll extend it when >it's singular. > >> >>>Doing things like attacks in eval and mobility and scans for all kind of things >>>which are trivial for chessplayers and i do not even dare to write down the name >>>for here, they slow down once engine. >> >>>I would search 3 ply at 1991 hardware with it, simply because the code size is >>>so huge, the nps at 1991 machine (i had a 10Mhz XT at the time) would be around >>>a 100 nodes a second or so. >> >>You are overreacting of course. > >Well of course when programming for a 10Mhz machine i would add huge selectivity >too, but i'm just talking about a theoretical math here now. > >My code size doesn't even fit within the ROMs you had in 1991 :) > >>>My point is would you have become world champion in 1991 searching 3 ply? >> >>8-10 plies was sufficient. > >8-10 plies at 10Mhz with for its time a great eval is really a grandmaster piece >of work. I actually was not so long ago at a friend of mine (IM) having a >chessmachine with inside an Ed Schroeder program. I really was amazed that you >got such a depth out of such a tiny hardware! > >In fact it completely outsearches diep 1997 which got 8 ply at the world champs >1997 at a PII300Mhz. > >> >>>I very deliberately ask it this way, because fritz3 (1995) searching at todays >>>hardware handsdown would search 20 ply in any middlegame, when it would be >>>converted. Apart from that it single cpu would search 3.5 million nodes a second >>>hands down. >> >>20 plies? >>Come on. > >No kidding. > >Huber clearly has proven that with MTD and a simple eval (basically material) >you can search depths of 30+ ply. > >The passive way in which fritz3 developed its pieces is very helpful. You get >*everywhere* nullmove cutoffs. > >With an agressive tuned engine such a thing is of course a lot more difficult to >do, if not nearly impossible at todays hardware. > >> >> >>>Todays fritz searched in 2003 world champs at a quad xeon 2.8Ghz about 13-15 >>>ply. >>> >>>The 2003 fritz at a 386 , 10Mhz would have a problem getting beyond 4 ply. >> >>I don't believe that. > >In 1999 fritz searched 17 ply everywhere at a quad xeon 500Mhz in middlegame. > >In 2003 fritz at a quad xeon 2.8Ghz searched 14 ply in middlegame. > >Those 14 ply from fritz2003 however completely destroy that 17 ply from >fritz1999. > >I know why this happens. I see it at many engines including DIEP. I can only say that number of plies is meaningless. It even does not mean that it is better in tactics. I can search more than 100 plies forward if I do enough reductions and every move is reduced by at least 10 plies. I do not understand why do people discuss about it. Uri
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