Author: Jeremiah Penery
Date: 17:21:04 02/03/02
Go up one level in this thread
On February 03, 2002 at 19:57:59, Robert Hyatt wrote: >On February 03, 2002 at 13:43:28, Jeremiah Penery wrote: > >>On February 03, 2002 at 07:40:27, Albert Silver wrote: >> >>>I'm a bit fuzzy on the accuracy of the PV we're seeing in the logs then. >>>Presuming that the PVs are only the software PVs, then these may still have been >>>subject to changes afterwards, no? After all, it's not uncommon to search to a >>>given depth and say that move A is best, but with greater depth (as the hardware >>>will provide) move B is shown to be best. I haven't examined the logs in detail >>>as some here have, so I'm presuming that such an inconsistency isn't there, but >>>if the hardware extensions aren't capable of changing the decision making, what >>>good are they? Or were they simply fortunate that this never happened in the >>>match and that is why we don't see it in the logs. I.e. a main move in the >>>software-based PV that was different from the move actually played due to later >>>corrections provided by the hardware extensions. >> >>It seems this is what happened on the famous move 36 of game 2, where it >>suddenly changed its mind from Qb6 to axb5. I don't know if it happened >>elsewhere. > >Not at all, there. It just used way more time to find a new best move as >the previous best move had dropped in score significantly. This is the relevant portion of the log: --> 35. Bxd6 <-- 5/46:59 --------------------------------------- hash guess Bf8d6b,Guessing Bxd6 8(4) #[Qb6](30)[Qb6](30) 30^ T=1 qf2b6 Qe8e7 pa4b5P Ra8b8 qb6a6P Pe5e4 bc2e4P Qe7e5 pg2g4 Rc8e8 be4g2 Qe5h2 kg1f1 Re8e3 qa6c6 Re3c3p 8(6) #[Qb6](61)[Qb6](61) 61^ T=1 qf2b6 Qe8e7 pa4b5P Ra8b8 qb6a6P Pe5e4 bc2e4P Qe7e5 pg2g4 Rc8e8 be4g2 Qe5h2 kg1f1 Re8e3 qa6c6 Re3c3p 8(6) #[Qb6](87)################################ 87 T=5 qf2b6 Qe8e7 pa4b5P Ra8b8 qb6a6P Pe5e4 bc2e4P Qe7e5 pg2g4 Rc8e8 be4g2 Qe5h2 kg1f1 Re8e3 9(6) #[Qb6](79)################################ 79 T=18 qf2b6 Qe8e7 pa4b5P Ra8b8 qb6a6P Pe5e4 bc2e4P Qe7e5 pg2g4 Rc8e8 be4g2 Qe5h2 kg1f1 Re8e3 10(6)<ch> 'Bd6' #[Qb6](74)################################ 74 T=82 qf2b6 Qe8e7 pa4b5P Ra8b8 qb6a6P Pe5e4 bc2e4P Qe7e5 be4f3 Rc8d8 qa6a7 Qe5c3p bf3h5 11(6)[PT=551]?[4 sec (main.c:1391)] #[et1 551 sec][Qb6](48)#[axb5](63) 63 T=416 pa4b5P Pa6b5p qf2b6 Ra8a2r ra1a2R Bd6c7 qb6e6 Kg8h8 bc2e4 Rc8b8 ra2a6 Qe8d8 pd5d6 Bc7b6 --------------------------------------- --> 36. axb5 <-- 4/40:28 Qb6 dropped in score from 74 to 48. If they used pawn=128, that's like 1/5 of a pawn - I would hardly call that a "significant" drop in score, worthy of more than doubling the normal time limit. But you may be right, in that this is a case of "normally" finding a better move. IMO, it's a bit difficult to tell exactly what's going on in their logs sometimes.
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