• Need help with gamblegammon formulas/calculations.

    From MK@21:1/5 to Axel Reichert on Thu Sep 8 04:29:36 2022
    I can't help going back to somethings said in the thread
    "Some thought on the fascinating and elusive luck".

    https://groups.google.com/g/rec.games.backgammon/c/eIKGjPQXISU/m/rzpNtdqUAAAJ

    On August 28, 2022 at 6:41:02 AM UTC-6, Axel Reichert wrote:

    I found some old "mutant" session results with expert
    checker play mimicking GNU Backgammon and random
    cube play (double, hold, beaver, take, pass). After 1000
    games the mutant was trailing with 17394 points versus
    gnubg's 114822.

    As I had indicated before, that is 15% win rate for the
    "mutant" with "zero cube skill".

    I wanted to know the "cube error rate" for the mutant
    which would be easy to figure out, if Axel shared his
    game files, by just letting XG or Gnubg analyse them.

    Since he will neither share the game files or help with
    calculating it, I'm trying to do it myself by deriving it
    from the "overall/average error rates" by XG or Gnubg.

    With combined checker and cube error rate, 15%-85%
    win rates require between 415 to 575 ELO difference
    between the players. For example, to win 15% against
    a bot of "supernatural" level, a player would need to be
    between "advanced" and "intermediate" level. See:

    http://www.columbusbg.org/Ratings/

    http://www.bgonline.org/forums/webbbs_config.pl?read=53409

    https://www.gnu.org/software/gnubg/manual/html_node/Overall-rating.html

    In Axel's experiment against "expert" (checker) level,
    the "random player" would have to be of about 1,500
    ELO, i.e. "casual player" which is higher than "beginner"
    and "distracted/awful".

    If the same holds true also for cube error alone, I think
    it would be quite telling about the so-called "cube skill".

    I'm assuming that if I can eliminate the checker skill
    from the equation, I should be able deduct the cube
    skill from the bot's overall/average error rate number.

    I looked but could find any documentation on how the
    bots use the checker and cube error rates to come up
    with an overall/average error rate. Does anyone know
    how XG or Gnubg figures it out?

    XG also calculates "expected win percent" based on
    the overall error rate. I couldn't find anything about how
    it calculates that either. I would appreciate any direct
    answers or links to relevant documentations.

    As you may have guessed, what I'm after is to show
    that if there was as much cube skill as hyped, random
    cube player could not achieve a 15% win rate...

    MK

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  • From Axel Reichert@21:1/5 to murat@compuplus.net on Sat Nov 19 09:32:05 2022
    MK <murat@compuplus.net> writes:

    if there was as much cube skill as hyped, random cube player could not achieve a 15% win rate...

    Try to estimate how often a game will be played to conclusion and then
    think about what this amounts to with equal checker play. No surprise
    here.

    Axel

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  • From MK@21:1/5 to Axel Reichert on Sat Nov 19 16:04:42 2022
    On November 19, 2022 at 1:32:07 AM UTC-7, Axel Reichert wrote:

    MK <mu...@compuplus.net> writes:

    if there was as much cube skill as hyped, random
    cube player could not achieve a 15% win rate...

    I'm so elated to see you take interest in this
    2.5 months old thread that nobody else had
    anything to contribute thus far.

    Try to estimate how often a game will
    be played to conclusion

    I wouldn't know how to do this estimate. Can
    you explain how can it be done, if you know?

    and then think about what this amounts
    to with equal checker play.

    Even after you will give me your estimate of
    the rate of games being played to conclusion,
    I still wouldn't know how to calculate what win
    rate it would amount to. As a mathematician,
    can you explain to me how one could do that,
    if you know?

    No surprise here.

    You (and your certain mathematician ilk) keep
    making such dismissive statements without
    offering any predictions, for us to later see if
    the results should or shouldn't "surprise" us...

    MK

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