Author: Ulrich Tuerke
Date: 08:00:14 06/18/01
Go up one level in this thread
On June 18, 2001 at 10:51:12, Bas Hamstra wrote: >On June 18, 2001 at 08:33:21, Ulrich Tuerke wrote: > >>On June 18, 2001 at 08:28:08, Bas Hamstra wrote: >> >>>On June 17, 2001 at 01:09:50, Robert Hyatt wrote: >>> >>>>On June 16, 2001 at 22:59:06, Vincent Diepeveen wrote: >>>> >>>>>Hello, >>>>> >>>>>From Gian-Carlo i received tonight a cool version of crafty 18.10, >>>>>namely a modified version of crafty. The modification was that it >>>>>is using a small sense of Singular extensions, using a 'moreland' >>>>>implementation. >>>>> >>>> >>>> >>>>Instead of modifying Crafty to simulate Deep Blue, why didn't you >>>>modify Netscape? Or anything else? I don't see _any_ point in >>>>taking a very fishy version of crafty and trying to conclude _anything_ >>>>about deep blue from it... >>>> >>>>Unless you are into counting chickens to forecast weather, or something >>>>else... >>> >>>I don't agree here. It is fun. Maybe not extremely accurate, but it says >>>*something* about the efficiency of their search, which I believe is horrible. I >>>think using SE and not nullmove is *inefficient* as compared to nullmove. We >>>don't need 100.0000% accurate data when it's obviously an order of magnitude >>>more inefficient. >> >>May be you are right, if the program is running on a PC. However if you can >>reach a huge depth anyway because of hardware, may be you can afford to use >>this, because it doesn't matter too much wasting one ply depth ? > >I don't see why inefficiency becomes less of a problem at higher depths. >Nullmove pruning reduces your effective branching factor to 2,5 where brute >force gets 4,5. So you could suspect at higher depths the difference in search >depths grows, starting with 2 ply, up till how much, 5 ply? > >Of course nullsearch has holes, but they are certainly not big enough to offset >a couple of plies, or none would use nullmove! In practice a n ply nullmove >search sees more than a n-2 ply BF search. > >Keeping that in mind, give Crafty 1000x faster hardware. It would search at >least 20 ply (normally 13 average according to Bob plus at least 7). I can tell >you DB does not search 18 ply BF. Therefore Crafty would in principle see more, >given the same eval. The SE thing only makes it worse. > >>I rather doubt that you can really learn something about Deep Blue this way. > >I don't see why not. He simply shows how inefficient their search is. Where does >Vincent's "emulated" search fundamentally differ from DB's, in your opinion? Except for the authors, nobody knows. That's the problem. We can't even be sure if they had some kinds of pruning. If I got it right, their "engine" was a combination of software and hardware implemented stuff. So, you cannot just scale the crafty results by some factor and compare then with DB results. DB executed on a platform which is very different from todays PCs. IMHO, the idea of simulating DB by some modified crafty is just ridiculous. I think, it's rather one of Vincent's jokes. Best regards, Uli >Tell him, he will adjust it. He is not emulating DB, of course, just their >search. > > >Best regards, >Bas.
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