Author: Robert Hyatt
Date: 17:30:25 04/24/01
Go up one level in this thread
On April 24, 2001 at 13:59:03, Vincent Diepeveen wrote: >On April 24, 2001 at 13:37:02, Robert Hyatt wrote: > >>pa4b5P Pa6b5p ra2a6 Nd6b7 bc5e3 Nb7d6 ra6a7 Bf8e7 >> 9(6) #[axb5](49)#################################### 49 T=55 >>pa4b5P Pa6b5p ra2a6 Nd6b7 bc5b6 Ra8a6r ra1a6R Nb7d6 >>10(6) #[axb5](49)##################################### 49 T=160 >>pa4b5P Pa6b5p ra2a6 Nd6b7 bc5f8B Qe8f8b ng3f5 Ra8a6r ra1a6R Rc8b8 >>11(6) #[axb5](49)#[Nf5](50) 50 T=308 >>ng3f5 Nd6f5n pe4f5N Pb5a4p bc2a4P Bd7a4b ra2a4B Qe8d7 bc5f8B Rc8f8b pf5f6 Qd7d5p > >Very confusing is whether it's a 11 ply PV or 12 ply pv. What is the confuision. Hsu said "11(6) means 11 plies nominal in software, 6 more plies in the chess chips." What can _possibly_ be confusing about that? > >the moves with n or N behind it means captures. DB extends in software >nearly all captures. I see around 3 non capturing moves here. Where do you get that? Their main extension is the singular extension. Captures don't trigger that every time. > >So 5 or 6 ply in software + capture extensions >(either recapture extensions or SE) >+ 6 ply in hardware. > >Very logical. > >note it's a 12 ply PV you see here *not* a 11 ply pv. Vincent... you are trying to make up the rules as you go. I specifically asked Hsu about the depth. Your interpretation is totally off-the-wall and irrelevant to the discussion. He said that the 11 above means that the software was started with a depth of "11", which would be reduced by one for each ply searched, and extended as indicated based on their normal extension logic. When depth reaches zero, they then give that position to a chess processor which then searches from that position for N plies, where N in this case is 6 more. The only difference is that singular extensions don't happen in the hardware. The chess processors _can_ probe a hash table. But he reported that he did not have time to design a 16-port memory module for each chess board... so the 1997 version didn't do hash probes. But only because he didn't have time to do it, not because it is impossible to do. > >I get way longer lines at 12 ply with extensions turned on as this :) So what. You don't have the same problem. They used 32 processors. A single processor searched about 1/2 way thru the nominal software depth, then positions were farmed out to 32 nodes on the SP (which use message passing for communication and have distributed memory). After depth goes to zero, the remainder of the search was done by chess processors that have _no_ hash memory, and _no_ PV facilities... Which means they will _never_ see the part of the PV searched by the chess hardware. And it is likely that they will never see all of the software PV since the PV was searched by different processors with no shared hash... Looking at the length of the PV is meaningless, and I have pointed this out before. They can _not_ get a PV from the chess hardware. _period_. It is simply impossible as it was not designed into the processors, and with no hash table, there is no other way to do it... > >>qf2g3 Pg7g5 >>--------------------------------------- >>--> 33. Nf5 <-- 7/65:41 >>--------------------------------------- > >This is caused by 30 diff processors with SE implemented. >I have those huge lines too in DIEP when i turn on all extensions! > >No big deal. > >If 6(6) would mean 6 ply in software and 6 ply in hardware, >then why do we see only 5 ply line? See above. I get short PVs all the time. Since their hash is distributed over 32 nodes, who knows what gets overwritten, and when... > >Even if you overwrite on an SP computer you still get 6 ply! Nope. They reconstruct PV from hash, since they can't back the PV up from endpoints due to hardware. > >Now the theoretic impossibility of searching 17 ply fullwidth >*with* all those extensions the first 11 ply. > >Apart that each search line must be like 15 ply then or so, >It's going to use up a lot of nodes. > >For deep blue it would cost around 5^6 more as the nodes they got in 1997! > >>Again I reiterate, the notation 11(6) means 11 plies in software search, >>6 plies in the hardware, plus the quiescence in hardware. There is _no_ >>argument with this. Simply ask any of the DB guys. 11(6) is a total of >>17 plies of search. > >Noop it is not Bob. It is 11 or 12 plies of search from which 6 ply >in hardware. Makes sense. Logical and clearly visible from the lines. > No it doesn't. You don't get to directly contradict the DB team, just because you can't imagine how it could be done. If half of the search were done by the chess processors, you would _never_ see a 12 ply PV, since the chess processors can't provide _any_ PV at all. >The first few ply > >Note that if it would be 11 ply of search with pruning + 6 ply in hardware, >then deep blue is the tactical worst program in history as it sees >Bf5 in game 6 at 8(6) which would be 14 ply then, which doesn't make >sense! Not even if you forward prune a lot! > >Shredder needs 8 ply for it too. It's a tactical queen win. >Shredder is doing recapture extensions as far as i know. > >If i turn on extensions in diep i also need 8 plies. without recapture >extensions i need 9 or 10 ply. > >Idem for other progs! > >Best regards, >Vincent > So? Db is not "other progs"...
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