Author: Slater Wold
Date: 12:06:05 09/01/01
Go up one level in this thread
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
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