Author: Robert Hyatt
Date: 20:20:50 03/27/00
Go up one level in this thread
On March 27, 2000 at 11:15:23, blass uri wrote: >On March 27, 2000 at 09:53:57, Ed Schröder wrote: > >>On March 27, 2000 at 09:06:01, Robert Hyatt wrote: >> >>>On March 25, 2000 at 23:13:49, Tina Long wrote: >>> >>>>On March 25, 2000 at 14:28:13, James Robertson wrote: >>>> >>>>>On March 25, 2000 at 13:41:28, Roger wrote: >>>>> >>>>>>Would tablebases for Tiger have changed this result at all? >>>>>> >>>>>>Roger >>>>> >>>>>Maybe a quarter of a point.... My experience with tablebases is that if the >>>>>program is moderately smart it doesn't benefit tremendously from them. >>>>> >>>>>James >>>>> >>>>Ed Schroder said about 6 months ago that Tablebases were worth about 10 points >>>>on the SSDF scale. >>>> >>>>I'm 70% sure he said that! I'm 100% sure that Ed said once that something was >>>>worth very little rating points. >>>> >>>>I'm glad I could add some real detail to this discussion. >>>> >>>>Tina Long >>> >>> >>>Ed is wrong there. it is _amazing_ how many comp vs comp games end up in >>>krp vs kr, with the side without tablebases losing most of those. There are >>>other endings too (KQP vs KQ, see for example crafty vs nimzo in the ICCT >>>tournament last month). >>> >>>The wrong way to test this is to play A with, vs A without. the right way to >>>test this is A without vs B without, then A with vs B without. But A ought to >>>be reasonably close to B without tablebases... >> >>Tablebases have a great future no doubt. But what is available at the >>moment (4-5 pieces) its value for Rebel is not more than 5-10 elo I >>would say because: >> >>a) most cases are simply covered by chess knowlegde; >> >>b) the loss of speed during search because of all the >>disc access. > >I do not think that b is right because you save time by not searching positions >of 5 pieces. > >disc access is relevant only after a capture that leads to 5 pieces on the >board. >My simple logic says that if you search n plies forward then you can decide to >call tablebases only after a capture that leads to 5 pieces and only if the >caprure is at distance of n-d plies from the root when d is the minimal numner >that searching d plies forward is slower than calling tablebases. > > That is all correct. Disk access is _not_ a problem. It doesn't slow me down enough to be a problem at all, and the gain more than offsets the I/O time... and if you cache stuff right, and hash the results right, the penalty drops to almost nothing for most positions... And the gain... :) >The only loss of speed that I can see is in case that you have no tablebases >calls because of checking one if command: > >If capture leads to 5 pieces and depth<=(n-d) then call tablebases. > >I guess that the loss of speed in this case is very small. >> >>So I don't think I am wrong when the subject is Rebel. >> >>Things might change dramatically when for instance the complete >>6 pieces become available. +100 elo easily for chess programs. > >I guess that +100 elo is too optimistic even with 6 men tablebases. >Uri
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