Author: Robert Hyatt
Date: 19:59:52 09/01/01
Go up one level in this thread
On September 01, 2001 at 15:45:12, Uri Blass wrote: >On September 01, 2001 at 15:06:05, Slater Wold wrote: > >>On September 01, 2001 at 11:00:37, Ed Schröder wrote: >> >>>On September 01, 2001 at 09:55:25, Robert Hyatt wrote: >>> >>>>On September 01, 2001 at 08:48:00, Vincent Diepeveen wrote: >>>> >>>>> >>>>>You are entirely right Ed, i have singular extensions inside diep now >>>>>and play with them turned on tournaments now. first tournament i played >>>>>with them turned on was back in 1994 the dutch open championship, >>>>>but my implementation sucked bigtime there. Then in paderborn 2001 i >>>>>used a better implementation with big reduction factor (R=3) and >>>>>also in combination with other extensions. The reason i have them >>>>>inside diep now is >>>>> a) diep doesn't search very deeply so overhead isn't too big then >>>>> b) to solve testpositions quicker otherwise i need days to solve things >>>>> >>>>>However what i notice is that in mainlines in complex positions the >>>>>value of singular extensions is very limited. Of course if i'm already >>>>>won i see mates way before my opponent sees them (in middlegame) or >>>>>i see a win way before my opponent sees it, as well as that Rxf7 move >>>>>which ferret played against gandalf i see within seconds with within 90 >>>>>seconds the right score, but after all the only impact of singular extensions >>>>>is that they give a psychological good feeling "i'm not going to lose >>>>>because of a cheap trick if my program messes up". Of course combinations >>>>>can only be there and getting outsearched is only important if a program >>>>>plays completely anti positional chess. >>>>> >>>>>In normal game play and in sound positions, there the value of SE and similar >>>>>extensions gets hugely overrated i think. >>>> >>>> >>>>I don't believe they _hurt_ when done right. The _last_ report by the DB >>>>team suggested that SE was worth maybe 10-20 Elo rating points at most. Their >>>>first report suggested far greater improvement, but this was because it did far >>>>better on test suites. In matches, it won, but the margin of victory was much >>>>less than the test suite results suggested... >>>> >>>>My tests in CB produced the same results. Modest improvements in games, some- >>>>times wild improvements in test positions. But even though the improvement in >>>>games is very modest, that one game here or there is _still_ very important. >>>>That could be your game vs Kramnik in a big tournament, for example. >>> >>> >>>Then why is SE not in Crafty when SE is an improvement? >>> >>>Ed >> >>I believe SE isn't going to hurt you when you're searching 200M nodes a second. >> >>Perhaps when you're search 1.0M or 1.5M, perhaps that extra squeeze of depth is >>not worth it, when it's taking up valuable time. >> >>Slate > >I believe that you are wrong. > >Deeper search without singular extensions is always important >Deeper blue could not see the move Qe3 in the pv against kasparov >when top programs of today can see it > >programs change their mind also at long time control because >deep search helps them to discover new things. > >I have examples from my correspondence games >when Deep Fritz changes it's mind after many hours >to a better positional move because of deep search >and I believe that it could not see it with singular extensions. > >Uri I don't understand _any_ of the above reasoning. (1) what says that SE is going to result in a much shallower search than normal? I've seen nothing like this. (2) what says that a SE search is not going to find a deep positional move better than a non-SE search? (3) What is any of this based on since the only people that have reported SE results have been the DB guys, and a little info on the last CB version from me?
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