Author: Robert Hyatt
Date: 11:29:17 07/03/02
Go up one level in this thread
On July 03, 2002 at 13:46:17, Christophe Theron wrote: >On July 02, 2002 at 20:20:37, Robert Hyatt wrote: > >>On July 02, 2002 at 18:54:49, Keith Evans wrote: >> >>> >>>Sorry to be anal retentive, but that's a bit of a stretch. Here's what they say: >>> >>>"The chess chips optionally support the use of an external FPGA (Field >>>Programmable Gate Array) to provide access to an external transposition table, >>>more complicated search control, and additional terms for the evaluation >>>function. In theory this mechanism would have allowed the hardware search to >>>approach the efficiency and complexity of the software search. Null move search >>>was also explicitly supported by this method. Due to time constraints, this >>>capability was never used in Deep Blue." >>> >> >> >>Read on. On page 67, section 4.1, item 3, "mate threat". >> >>"It is relatively simple using a null move search to detect if there is a >>threat in the current position.... The Deep Blue implementation ... >> >>Which matches what I said. They had support for a normal null-move search >>had they wanted to use it, but they did use null-move to detect threats, >>something that has been done before (and several of us use a form of mate >>threat extension based on this idea presently). >> >>So they used null-move in at least one way, without using it as a forward >>pruning algorithm, which fits with Hsu's "no errors in the search" theme he >>mentioned repeatedly over the years. Extra extensions were one thing to him, >>but outright errors were something else not to be tolerated. Right or wrong. >>I obviously disagree about the errors in a normal null-move search, but I >>can hardly argue with their success... > > > >That's my point as well. > >I don't argue about their success. > >I'm just saying that they succeeded because their chips were very fast. So fast >that they allowed them to use inferior search techniques and still succeed. > Could you not make the _same_ statement about chess 4.0 in 1975? Until that point _everybody_ was doing forward pruning like mad. They discovered that a a shallower full-width search had fewer errors and they stomped everybody into the ground until everyone converted... was _their_ search "inferior" or just "different"??? >That's why I'm saying that we should not be impressed about all they have done. > >Their search is not at the level of the amateur programs that enter the W(M)CCC >for example. Neither is their hardware. DB is a _total_ package. You might find out that your forward pruning hurts rather than helps at the speed and depth they were capable of reaching... > > > > Christophe > > > > > >>>As a verification guy my motto is - "If it's untested, then assume it's broken." >>> If I had been regarded highly enough to review this paper before publication, >>>then I would have crossed out this paragraph. >>> >> >> >>Wouldn't disagree there.
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