Author: Andrew Dados
Date: 11:14:37 05/04/01
Go up one level in this thread
On May 04, 2001 at 13:39:18, Robert Hyatt wrote: >On May 04, 2001 at 11:19:08, Uri Blass wrote: > >>On May 04, 2001 at 10:41:34, Robert Hyatt wrote: >><snipped> >>>There are other possible explanations here too. >>> >>>The most likely is that the first search you gave produced a score for depth >>>16. It started on depth=17 but failed to produce a score/move before it timed >>>out. >> >>This explanation does not seem to be correct. >>The score of deeper blue was clearly lower after trading queens. >> >>It is known that programs after failing low use more time and I do not see that >>deeper blue used more time for Qxf1. >>It used only 168 seconds for Qxf1 based on the logfile. >> >>Another point is the fact that the score was no constant in the first iterations >>after Qxf1 Rxf1. >>I expect constant score in the first iterations if the score is based on >>previous search. >> >>Uri > > >Doesn't mean that is what it is doing. You search to depth=16 and get a score >of (say) +.01 > >you start the depth=17 search, which is going to drop the score to -.5, but you >don't have time to get the move back. > >you make the move and start pondering. > >_instantly_ you find the -.5 score as it is left in the transposition table >from the search that timed out. > [snip] Now, Bob, have a look at that again: 1) Previous, timed out search: ============================= 11(6)[TIMEOUT] 2 T=168 Qb5f1q ra1f1Q Ph6h5 kh1g1 Pb7b5 kg1h1 Kg8f8 kh1h2 Ne5g4 ne3g4N Ph5g4n pf5f6 Rd8d6 kh2g1 Re8e6 rf1e1 2) Next search: ============================== 7(4) #[h5](-30)[h5](-30) -30v T=0 Ph6h5 kh1g1 Pb7b5 kg1h1 Kg8f8 kh1h2 Ne5g4 ne3g4N Ph5g4n pf5f6 Rd8d6 kh2g1 Re8e6 rf1e1 7(6) #[h5](-66)############################## -66 T=1 Ph6h5 kh1g1 Pb7b5 kg1h1 Kg8f8 kh1h2 Ne5g4 ne3g4N Ph5g4n pf5f6 Rd8d6 kh2g1 Re8e6 rf1e1 8(6) #[h5](-50)############################## -50 T=5 Ph6h5 kh1g1 Pb7b5 kg1h1 Kg8f8 kh1h2 Ne5g4 ne3g4N Ph5g4n pf5f6 Rd8d6 kh2g1 Re8e6 rf1e1 Note: a) all 3 lines above are searches below previous 11(6) depth. They all produce same PV and different scores. They all should give exact same score if TT probe was hit from previous search. If they give different scores, then TT was owerwritten, then in that case second and third PV would give score similar to previous search-to-corresponding-depth score. Hard to believe *all* PV nodes were overwritten and then exact, same PV was found. b) it took T=5 seconds to get 8(6), so either something is broken in DB TT (it shows exact PV line as previous) or DB didnt reuse TT from search to search, which makes sense if it was doing some preprocessing. As you noted above 8(6) depth should return _instantly_. -Andrew-
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