Author: Ed Schröder
Date: 10:53:52 07/22/00
Go up one level in this thread
On July 22, 2000 at 10:08:15, Robert Hyatt wrote: >On July 22, 2000 at 05:44:36, Ed Schröder wrote: > >>On July 21, 2000 at 22:27:45, Robert Hyatt wrote: >> >>>On July 21, 2000 at 19:16:41, Ed Schröder wrote: >>> >>>>On July 21, 2000 at 15:29:26, Robert Hyatt wrote: >>>> >>>>If you don't mind I only answer those points not earlier discussed >>>>(enough) to avoid ending up in endless circles. >>>> >>>> >>>>>>2) DB is no brute force program (as you always have claimed). Quote >>>>>>from the IBM site: >>>>>> >>>>>> "Instead of attempting to conduct an exhaustive "brute force" >>>>>> search into every possible position, Deep Blue selectively >>>>>> chooses distinct paths to follow, eliminating irrelevant searches >>>>>> in the process." >>>>>> >>>>>>I always said this after I had seen the log-files. It beats me how you >>>>>>always have claimed the opposite on such a crucial matter presenting >>>>>>yourself as the spokesman of Hsu even saying things on behalf of Hsu >>>>>>and now being wrong on this crucial matter? >>>>> >>>>>Sorry, but you are wrong and are interpreting that wrong. DB uses _no_ >>>>>forward pruning of any kind, this _direct_ from the DB team. The above is >>>>>referring to their search _extensions_ that probe many lines way more deeply >>>>>than others. If you want to call extensions a form of selective search, that >>>>>is ok. It doesn't meet the definition used in AI literature of course, where >>>>>it means taking a list of moves and discarding some without searching them at >>>>>all. >>>> >>>>The quoted text describes DB as a selective program, no brute force. I >>>>don't see how you can explain it otherwise. The text is crystal clear. >>>> >>>> >>> >>>Why don't you simplyh ask Hsu, or are you afraid you will get an answer >>>you don't want? DB was _always_ brute force. Every document written about >>>DB said this. The paragraph you are quoting is talking about "selective >>>search extensions" which was one of the real innovations from the Deep Thought >>>development (singular extensions, later used by Lang, Kittinger, Moreland, >>>Hyatt, who knows who else). >> >>I disagree. Extensions are always selective. Some moves are extended >>some don't and that makes that extensions is a selective process by nature. >>So the text (about brute force) can't be related to the previous sentence >>(about extensions). They made 2 statements (not one). >> > >There is a difference. It is one thing to search move A one ply deeper than >move B, based on some (hopefully good) criteria. It is quite difference to >simply choose to take move B and not search it at all from the current >position. One easy example is that in the q-search, I throw out _all_ >non-captures and consider them no further, while captures continue to grow >trees below them... That I call pruning :) >> >>>You _know_ they were basically in the same mold as the rest of us. This has >>>_never_ been in doubt. >>> >>>If you do doubt it, just ask the horse's mouth, since you don't want to believe >>>me. >>> >>> >>> >>>> >>>>>This _was_ deep thought. It was doing about 2M nodes per second in 1995, >>>>>according to Hsu. >>>> >>>>Then Hsu is wrong or the IBM site. >>>> >>>>Quote from the IBM site: >>>> >>>> "Deep Thought acquires 18 >>>> additional customized chess >>>> processors and emerges as >>>> Deep Thought II. It now is >>>> running on an IBM/6000 and >>>> can search six to seven million >>>> chess positions per second. >>> >>> >>>That was correct. But as I said (after a conversation with Hsu) it _never_ >>>really ran at that speed. The few times they tried to use all the hardware, >>>things didn't work out very well (this was mainly used during the Fredkin >>>stage II matches, where they physically shipped the machine (a single Sun >>>workstation + the VME cards) to remote locations. >>> >>>Hsu has said point blank, the most recent version of DT was searching about >>>2M nodes per second. I take him at his word, since he built the thing... >> >>The only thing that counts here is the contradicting data: >> >>1991: IBM 7 million >>1995: Hsu 2 million >> >>Now who to believe that's the question. >> >> > > >Simply ask Hsu. wouldn't you think??? I used the 7M speed in a post >once (either here or in r.g.c.c) and he sent me a private email correcting >the number. I believe 7M was the peak number, while 2M was the _effective_ >number and matched the 200M number from DB. As I said before, everybody >used to report MAX or TYPICAL NPS, but the number was RAW. IE for Cray Blitz, >my 8 cpu numbers were 8x my one cpu numbers. Hsu changed the way he reported >this so that the numbers were more realistic. IE with CB you might conclude >that it would search to the same depth in 1/8th the time, since the RAW NPS was >8X the one CPU number. That didn't happen. With Hsu's numbers, if a single >chip went 2M, he says that 480 CHIP DB won't search the same tree in 1/480th >of the time. Rather it will search it in 1/100th the time (2M / 200M, rather >than 2M / 1B. >If you want to use 7M for DT, then lets use 1B for DB2, as that is comparable. You made my day.... :) Good moment to end the discussion. Ed >If you want to use 200M for DB, then 2M for DT is the right number. All right >from the "horse's mouth" if you know what I mean... > >I don't believe he started using the effective number until his PhD >dissertation, which was well after DT.02 was out and running... > > > > > > > >> >>>> >>>>6 to 7 million NPS. This in the year 1991 so 4 years before the Hong Kong >>>>event. So according to Hsu and/or IBM in 1995 the machine dropped from 7 to >>>>2 million NPS?? One might expect the opposite, a faster machine after >>>>4 years but not a slower one. Something ain't right with these numbers. >>> >>> >>>Simply email Hsu... it was his box. He can tell you what you want to >>>know... >>> >>> >>>> >>>> >>>>>Fine. Again, Hsu is a liar. If that is what you want to think. Here is >>>>>an excerpt from him that might help: >>>>> >>>>>=============================================================================== >>>>>Web-based DB Jr uses a single card, a random opening book (including >>>>>fairly bad lines) and one second per move (a quarter of which is used >>>>>in downloading the evaluation function, and the search extensions are >>>>>more or less off due to the very short time). It probably plays at around >>>>>2200, which is usually sufficient to play against players in random marketing >>>>>events. Repetition detection is also turned off (The web-based program >>>>>is stateless). The playing strength of "DB Jr." spans a quite wide range, >>>>>depending on the setup. The top level, which we used for analysis and >>>>>in-house training against Grandmasters, is likely in the top 10 of the >>>>>world. >>>>>================================================================================ >>>> >>>>I said the contradiction is in the private emails so you can't know. >>>> >>>>Ed >>> >>> >>>No, but I believe from the above, which is also private email, there is >>>absolutely no confusion in what "web DB Jr" was. It is _very_ clear, and >>>not open to misinterpretation, wouldn't you say?? >>> >>>It was thrown together at the request of marketing guys. And "thrown together" >>>is a pretty accurate description. He says "2200". In another email he said >>>"2200 might have been optimistic"... >> >>Every time it is something else. I stopped believing it. >> >>Ed > > >That is your choice of course. I know him a bit better...
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