Author: Uri Blass
Date: 12:17:42 11/14/03
Go up one level in this thread
On November 14, 2003 at 14:47:51, Tom Likens wrote: >On November 14, 2003 at 13:31:19, Uri Blass wrote: > >>On November 14, 2003 at 12:46:36, Tom Likens wrote: >> >>>On November 14, 2003 at 12:26:53, martin fierz wrote: >>> >>>>we all know computer chess has evolved a lot over the last years. the top >>>>programs are now battling (and beating) the very best players on the planet. >>>>mainly through consistency, but sometimes also with non-materialistic moves that >>>>computers would IMO not have made a few years ago (...Bxh2! by junior against >>>>kasparov, ...OO! giving up the exchange by fritz yesterday). >>>> >>>>question: is this progress more due to hardware or more due to software >>>>advancements? >>>> >>>>or in other words: if you took a top program of today (e.g. the current >>>>fritz/shredder/junior) and ran it on 5-year old hardware against a 5-year old >>>>fritz/shredder/junior version on today's hardware: which combination would win? >>>> >>>>cheers >>>> martin >>> >>>I believe the advances in hardware have allowed the programs to evaluate >>>things they wouldn't have attempted years ago, because of the resultant >>>reduction in search depth (the kiss of death). >> >>I do not believe it. > >I don't think you can radically reduce the depth a program searches and >not suffer somewhat strengthwise. A very sophisticated evaluation can >compensate for this to a point, but there is a definite crossover point where >significantly increasing the amount of knowledge in the evaluation, and thus >dramatically reducing the search depth, will result in a weaker program. >Lazy eval, hashing, extensions and pruning reduce this effect somewhat but >don't completely eliminate it. The trick is to hit the sweet spot, which is >different for every program. > >> A quick example, >>>a fair number of programs used to be largely piece-table driven (i.e. they >>>performed a large amount of evaluation at the root and used those results >>>at the tip of the search tree). While this is still a component of all the >>>top programs, most have been moving in the direction of more accurate full- >>>leaf evaluation because the hardware is fast enough to support it without >>>sacrificing too much depth. >> >>I do not think top programs of today sacrifice depth by full leaf evaluation. >>Top program of today are better than the top programs of the past at all time >>control including blitz. >> >>Uri > >I don't think they sacrifice depth either, because they are running on *much* >faster hardware. It wasn't that long ago when 50,000 nps was blazingly fast. >Now *everybody* does that and in fact 50k nodes/sec is considered slow. > >There have been tremendous software advances that Slate and Atkin had no >inkling of (null-move pruning is a good example). But I still contend that >the penalty for adding sophisiticated knowledge to the evaluation function >isn't as steep today as it was 20 yrs. ago. We talk about the last 5 years and not about the last 20 years so what happened 20 years ago is not relevant. Or perhaps, another way to think >about it is that the difference between searching 12 plies deep vs. 15 plies >deep isn't as dramatic strengthwise as searching 8 plies vs. 5 plies. > >Of course, if you can encode the knowledge *without* reducing the search >depth then it's a win-win (and your name is probably Fritz ;-) > >--tom I think that the search depth of shredder is not smaller than the search depth of Fritz. All the dilema between x plies and x+3 plies does not happen I remember that amir ban said that Junior is using less than 20% of its time in the evaluation function and it is not a root processor. Uri
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