Author: Robert Hyatt
Date: 09:31:39 02/16/06
Go up one level in this thread
On February 15, 2006 at 23:57:51, Peter Kappler wrote: >On February 15, 2006 at 23:26:28, Robert Hyatt wrote: > >>On February 15, 2006 at 17:35:06, Peter Kappler wrote: >> >>>On February 15, 2006 at 17:13:54, Robert Hyatt wrote: >>> >>>>On February 15, 2006 at 16:24:20, Uri Blass wrote: >>>> >>>>>On February 15, 2006 at 15:18:56, Robert Hyatt wrote: >>>>> >>>>>>On February 15, 2006 at 13:19:35, George Tsavdaris wrote: >>>>>> >>>>>>>On February 15, 2006 at 12:59:32, Peter Skinner wrote: >>>>>>> >>>>>>>>On February 15, 2006 at 12:55:56, Peter Skinner wrote: >>>>>>>> >>>>>>>>>Hello all, >>>>>>>>> >>>>>>>>>As promised by Vincent last week, he has entered Diep into CCT8. >>>>>>> >>>>>>>Nice but what hardware he will use? Any huge one or normal(fast).....? >>>>>>> >>>>>>> Also is this the most large number of participants for a CCT or there have been >>>>>>>and any larger....? >>>>>>> I remember very recently Hiarcs and an experimental Junior participating. Did >>>>>>>that happen in the last CCT or in another different than CCT tournament.....? >>>>>>> >>>>>>> Also 9 rounds with so many participants seems a bit short for me. Do you >>>>>>>consider increasing the number of rounds.....? >>>>>>> >>>>>> >>>>>>9 rounds is enough to find a clear 1st place for 512 opponents. :) >>>>> >>>>>This is correct if one program wins all the games but it will probably not >>>>>happen. >>>>> >>>>>> >>>>>>By the time this event ends, the top group will have all played each other. >>>>> >>>>>I am not sure of it. >>>>>In theory it is possible to have 10 winners with 6 out of 9 and in this case it >>>>>is clear that they need to beat weaker programs to get more than 4.5 out of 9 so >>>>>not every pair of winners played. >>>>> >>>>>Uri >>>> >>>>In practice this doesn't happen. The real problem is that by round 6, the >>>>winner is pretty certain, although three games against weaker opponents are >>>>left, and there the luck factor often lurks behind a pawn and jumps out to >>>>present a surprise and knock one of the top players off. >>>> >>> >>>I have to believe that you're half-kidding here. Surely you don't believe that >>> adding 3 more rounds increases the variance of the final result? >>> >>>-Peter >>> >> >>Yes, it absolutely does. Simple example: 4 strong programs, 12 weak ones. >>after round 1, you have 8 with 1, 8 with 0, the 8 with 1 include the top 4. >>After two rounds, the top four have two, the bottom four have 0, and the rest >>have 1 (assuming no draws). after 3 more rounds the top four have played. What >>now for those other 4 rounds? Other programs? With the luck factor increasing >>variance? >> > > >What is this "luck factor"??? It is something seen in _every_ tournament played. A weaker program stumbles into a winning position, either being lucky with the book, or just lucky in making a move it didn't understand was good, but which turned out to be good many moves later. I can refer you to the game Nuchess - Cray Blitz at the 1984 ACM event. We played a horrible-looking Nb8 move. But it later let us trade off all the pieces and win a pawn-race because white simply didn't understand unstoppable pawns. But had black not played that one ugly move, for the wrong reason, white would have won handily. Every tournament has a luck factor thrown in. Even in my human chess games, I occasionally stumble into something I had not forseen, and win because of it. > >If one of the strong programs loses or draws against one of the weak programs, >that's not luck - it's a signal that the program might not be as strong as you >thought. It can be luck plain and simply. You have three moves to choose between, at the depth you are searching, all three have _identical_ scores even though one will later turn out to be winning, one will turn out to be losing, and one will turn out to be pretty "equal". What determines which move your search chooses? Luck of move ordering at the root. Since the first move with equal scores will be chosen by alpha/beta. I can play a move that is lucky in that it wins even though I don't know it at the time, I can play a move that is unlucky in that it loses later in the game. That's luck, since it is based on random choice rather than any sort of chess knowledge or skill. > >It seems obvious to me that increasing the number of rounds always reduces the >variance of the final tournament standing, regardless of the distribution of the >participants' ratings. > Seems to me that if you look at events starting at round 6 and on, nothing much changes since the leaders have all played because of the Swiss pairing rules. But lower-rated programs still move up and down and a few collect right below the leaders. If all programs were pretty equal, extra rounds would not really make that much of a difference. But they are not equal, and strong vs weak in late rounds doesn't do a thing for overall result confidence. >-Peter > > > >> >>> >>> >>> >>> >>>>log2(#players) is a good number of rounds for starters. one more gives a couple >>>>of more top finishers a better final result. But too many and many of the final >>>>rounds are simply meaningless, as we've seen multiple times. For example, at >>>>the last WCCC they tried to fudge the round-robin pairing to put a few of the >>>>"interesting games" on the final few rounds. Didn't work out at all and the >>>>event was over early... >>>> >>>>There can always be too many rounds in a Swiss. >>>> >>>>9 is on the edge. Both in final results and in total time required to play 9 >>>>games...
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