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Will XG2 have a 'View Statistics' feature?

Posted By: Timothy Chow
Date: Monday, 4 April 2011, at 11:22 p.m.

In Response To: Will XG2 have a 'View Statistics' feature? (Ray Kershaw)

Yes, that's right; XG will report percentages of wins/gammons/backgammons for a rollout. These aren't the actual numbers of games/gammons/backgammons that you'll win from that position (playing both sides the way the bot plays them). With the cube in play, you'll win some games when your opponent drops your double. The reported percentages don't count this as a simple win; rather, it makes an estimate of how many wins/gammons/backgammons you would collect if the game were played out to the bitter end.

Thus, these numbers are often referred to as "cubeless" wins/gammons/backgammons, because when there is no cube then games of course must be played to completion.

However, they're not really cubeless wins/gammons/backgammons, because the presence of the cube affects the checker play. To obtain a proper estimate of the number of games you would win cubelessly, you should play out the rest of the game, moving the checkers the way you would move them if there truly were no cube in play. But this is not what XG does. XG plays the checkers ATS, in particular paying attention to any effect that the cube location and score might have on the proper checker play. When a rollout trial ends in D/P, it substitutes some funky estimate of "cubeless" wins/gammons/backgammons into its calculations.

So I call these numbers "pseudocubeless" to emphasize that they're not the actual win/gammon/backgammon percentages, nor are they even cubeless win/gammon/backgammon percentages. They're some sort of estimate of cubeless percentages, obtained by the above convoluted process.

Most people blur all the above distinctions and cavalierly say that one play "wins more games but loses more gammons" than another if that's what the pseudocubeless numbers indicate. Then they scratch their heads wondering why the numbers don't add up correctly.

Messages In This Thread

• Will XG2 have a 'View Statistics' feature?
  Timothy Chow -- Monday, 4 April 2011, at 3:41 p.m.
  • Will XG2 have a 'View Statistics' feature?
    eXtreme Gammon -- Monday, 4 April 2011, at 4:16 p.m.
    • Will XG2 have a 'View Statistics' feature?
      Timothy Chow -- Monday, 4 April 2011, at 6:28 p.m.
      • Will XG2 have a 'View Statistics' feature?
        Ray Kershaw -- Monday, 4 April 2011, at 9:43 p.m.
        • Will XG2 have a 'View Statistics' feature?
          Timothy Chow -- Monday, 4 April 2011, at 11:22 p.m.
          • Will XG2 have a 'View Statistics' feature?
            Ray Kershaw -- Tuesday, 5 April 2011, at 3:35 p.m.
            • Will XG2 have a 'View Statistics' feature?
              Timothy Chow -- Tuesday, 5 April 2011, at 11:04 p.m.
              • Will XG2 have a 'View Statistics' feature?
                Ray Kershaw -- Thursday, 7 April 2011, at 2:28 p.m.
                • Will XG2 have a 'View Statistics' feature?
                  Timothy Chow -- Thursday, 7 April 2011, at 11:13 p.m.
          • Will XG2 have a 'View Statistics' feature?
            Daniel Murphy -- Friday, 8 April 2011, at 10:32 a.m.
            • Will XG2 have a 'View Statistics' feature?
              Timothy Chow -- Friday, 8 April 2011, at 10:19 p.m.
              • Will XG2 have a 'View Statistics' feature?
                Daniel Murphy -- Saturday, 9 April 2011, at 12:07 a.m.
                • Will XG2 have a 'View Statistics' feature?
                  Timothy Chow -- Friday, 15 April 2011, at 10:59 p.m.
    • Will XG2 have a 'View Statistics' feature?
      leobueno -- Friday, 8 April 2011, at 10:45 p.m.