• GNU Backgammon is unsure about doubling. What about you?

    From Axel Reichert@21:1/5 to All on Sun Jul 3 22:03:56 2022
    I was astonished to see GNU Backgammon assess its own cube decision as
    "very bad" (> 0.16 equity loss). I am using different settings for
    evaluation (during the game) and analysis (after the game), but cannot
    remember a discrepancy this large. There is also a pronounced odd/even
    effect with respect to the plies.

    The score (after 5 games) is: gnubg 8, axel 6 (match to 11 points)
    Move number 52: gnubg on roll, cube decision?

    GNU Backgammon Position ID: 0DmAnUFtM8YhAA
    Match ID : MAFgAYAAMAAE
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ O: gnubg
    | O O O O X O | | X X O O | 8 points
    | O O O X O | | X X O O | On roll
    | | | X O |
    | | | |
    | | | |
    | |BAR| |^ 11 point match (Cube: 1)
    | | | |
    | | | |
    | X | | X |
    | X | | X |
    | X X | X | X O | 6 points
    +24-23-22-21-20-19------18-17-16-15-14-13-+ X: axel
    Pip counts: O 101, X 200

    I took ("When no clue, take, you might learn something"). What are your thoughts (about the position and suitable rollout settings)?

    Best regards

    Axel

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  • From pepstein5@gmail.com@21:1/5 to Axel Reichert on Mon Jul 4 13:19:37 2022
    On Sunday, July 3, 2022 at 9:03:59 PM UTC+1, Axel Reichert wrote:
    I was astonished to see GNU Backgammon assess its own cube decision as
    "very bad" (> 0.16 equity loss). I am using different settings for
    evaluation (during the game) and analysis (after the game), but cannot remember a discrepancy this large. There is also a pronounced odd/even
    effect with respect to the plies.

    The score (after 5 games) is: gnubg 8, axel 6 (match to 11 points)
    Move number 52: gnubg on roll, cube decision?

    GNU Backgammon Position ID: 0DmAnUFtM8YhAA
    Match ID : MAFgAYAAMAAE
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ O: gnubg
    | O O O O X O | | X X O O | 8 points
    | O O O X O | | X X O O | On roll
    | | | X O |
    | | | |
    | | | |
    | |BAR| |^ 11 point match (Cube: 1)
    | | | |
    | | | |
    | X | | X |
    | X | | X |
    | X X | X | X O | 6 points
    +24-23-22-21-20-19------18-17-16-15-14-13-+ X: axel
    Pip counts: O 101, X 200

    I took ("When no clue, take, you might learn something"). What are your thoughts (about the position and suitable rollout settings)?

    Best regards

    Axel

    Looks like a clear ND/T to me. However, I note several points.
    1) We are in the middle of Wimbledon.
    2) A new edition of the New Yorker just came online today.
    3) There are some great articles in the London Review of Books that I haven't read yet.
    4) Same as 3) for the New York Review of Books.

    How are points 1 to 4 relevant?

    They're relevant because they indicate that, with so much else to watch and read, I'm not
    exactly super-motivated to spend time defending my verdict.
    Obviously with a match lead, gnubg should be conservative with the cube.

    Paul

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  • From MK@21:1/5 to Axel Reichert on Mon Jul 4 14:53:26 2022
    On July 3, 2022 at 2:03:59 PM UTC-6, Axel Reichert wrote:

    I was astonished to see GNU Backgammon assess its
    own cube decision as "very bad" (> 0.16 equity loss)....

    GNU Backgammon Position ID: 0DmAnUFtM8YhAA
    Match ID : MAFgAYAAMAAE

    I took ..... What are your thoughts (about the position and
    suitable rollout settings)?

    It's hard to understand which is which but apparently Gnubg
    doubled (and you took) when it shouldn't double. If that's the
    case, 4-ply hint says ND (I rarely do rollouts) and says D/T is
    -0.281 which is almost twice the > -0.16 treshold.

    Since I don't understand (and don't want to underdtand bogus)
    detailed cube analysis numbers, I don't pay much attention to
    how Gnubg may be making "PR sacrificing" cube decisions but
    in the past I had caught and posted many examples of Gnubg's
    making "PR sacrificing" checker decisions during the game by
    looking ahead to upcoming dice rolls.

    How did your game end? Can you copy/paste it here as text?

    From now on, I may try to catch such cube "errors" even with
    my very limited understanding of the "cube skill bullshit"...

    MK

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  • From Timothy Chow@21:1/5 to Axel Reichert on Thu Jul 7 21:13:17 2022
    On 7/3/2022 4:03 PM, Axel Reichert wrote:
    I was astonished to see GNU Backgammon assess its own cube decision as
    "very bad" (> 0.16 equity loss). I am using different settings for
    evaluation (during the game) and analysis (after the game), but cannot remember a discrepancy this large. There is also a pronounced odd/even
    effect with respect to the plies.

    This is the sort of position that GNU and XG still have some trouble
    with. The match score also complicates matters. At 3-away/5-away,
    when most of the 3-away player's wins are gammons, but the 5-away
    player still has considerable winning chances, doubling is typically
    a mistake; for a start, it decreases the 3-away player's gammon value
    (possibly to zero, if the 5-away player redoubles). The take is easy
    and will probably be easy next turn as well.

    I suspect that the "contradictory" behavior you observed will be much
    reduced at a normal match score such as 7-away/7-away. Whatever
    heuristics GNU is using to adjust for the match score are probably
    not working too well in this position.

    Below is an XG rollout with stronger-than-usual settings. The
    standard rollout settings were yielding high-variance results,
    which is a sign that the bot doesn't understand the position
    very well. Even these settings were yielding pretty high
    variance, but at least the final result is in line with what
    I would expect from general principles (i.e., ND/T).

    XGID=aABBBbBcbB--C---Ac-ca-----:0:0:1:00:8:6:0:11:10

    X:Player 2 O:Player 1
    Score is X:8 O:6 11 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O O |
    | O | | O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | X O | | |
    | X X O O | | X O X X X |
    | X X O O | | X O X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 101 O: 200 X-O: 8-6/11
    Cube: 1
    X on roll, cube action

    Analyzed in Rollout
    No double
    Player Winning Chances: 62.75% (G:47.44% B:0.84%)
    Opponent Winning Chances: 37.25% (G:5.60% B:0.26%)
    Double/Take
    Player Winning Chances: 61.44% (G:48.89% B:1.13%)
    Opponent Winning Chances: 38.56% (G:5.92% B:0.32%)

    Cubeful Equities:
    No double: +0.609
    Double/Take: +0.411 (-0.198)
    Double/Pass: +1.000 (+0.391)

    Best Cube action: No double / Take
    Percentage of wrong pass needed to make the double decision right: 25.2%

    Rollout:
    2014 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 4-ply, cube decisions: XG Roller+
    Search interval: Large
    Confidence No Double: ± 0.018 (+0.591..+0.627)
    Confidence Double: ± 0.031 (+0.380..+0.442)

    eXtreme Gammon Version: 2.19.207.pre-release, MET: Kazaross XG2

    ---
    Tim Chow

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  • From Timothy Chow@21:1/5 to All on Thu Jul 7 21:17:25 2022
    On 7/4/2022 5:53 PM, MK wrote:
    in the past I had caught and posted many examples of Gnubg's
    making "PR sacrificing" checker decisions during the game by
    looking ahead to upcoming dice rolls.

    You still believe this nonsense? Even by your standards, this
    is nuts. How do you explain the fact that even when you change
    the dice seed and play from this position, GNU makes exactly
    the same decisions every time?

    ---
    Tim Chow

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  • From Stick Rice@21:1/5 to All on Sun Jul 10 17:18:05 2022
    The take is easy
    and will probably be easy next turn as well.

    Tim Chow

    Doubtful.

    Stick

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  • From MK@21:1/5 to Tim Chow on Tue Jul 19 04:25:04 2022
    On July 7, 2022 at 7:17:27 PM UTC-6, Tim Chow wrote:

    On 7/4/2022 5:53 PM, MK wrote:

    in the past I had caught and posted many examples of
    Gnubg's making "PR sacrificing" checker decisions
    during the game by looking ahead to upcoming dice rolls.

    You still believe this nonsense?

    Don't you yet?

    Even by your standards, this is nuts. How do you explain
    the fact that even when you change the dice seed and
    play from this position, GNU makes exactly the same
    decisions every time?

    This can become a multi-faceted interesting discussion.

    Let's start.

    First, I assume you mean if you change the dice seed not
    from this position but from previous position, i.e. before
    the bot makes its decision. Otherwise, it's already done
    and it's too late.

    Second, I assume you understand that when you say it
    will make the same decision, you mean "the same wrong,
    inferior decision", or else you would be missing the point
    by a mile...

    My comment was meant to be a semi-serious, semi-snide
    explanation, expecting that nobody else would ridicule
    themselves offering explanations.

    Do you realize and accept that your blabbering bullshit
    explantion is no better than mine that you sneer at...?

    Also, I was referring to past examples of checker plays
    which may have changed since then, while here we are
    talking a cube decision. Very different things...

    Starting with Jellyshit, I have argued for and provided
    statistical evidence for that games played with manual
    dice against the bots "enfold", "develop" in such easily
    observable different ways, that if anyone denies to or is
    incapable to see it, I won't take them seriously enough to
    debate with them.

    In the past, I was the one begging to be given a chance to
    prove my points. Now I don't give a shit. Except, of course,
    if you guys make it easy for me to demonstrate to you all,
    in a way open to the public and if you all are willing to bet
    money on it against me.

    I have given you step-by-step instructions to prove it to
    yourselves in the past. I don't think that any of you ever
    made a genuine effort. I won't waste my time again with
    repeating them but I can perhaps add this one new way.

    Recently, I posted here an external dice dll for XG reading
    numbers from text files, including the source code and
    instructions to compile it as a dll or as an exe.

    Gnubg already has the feature of reading dice from files.
    So, let it read from a text file and use my dll to make XG
    get rolls from the same file. Play money games against
    both bots thus with the same dice rolls.

    Per you guys' own argument, (and mine:)) both bots play
    almost exactly the same way, except for very well known
    differences like their playing the opening 64's and a few
    others. You will see that depending on who rolls the dice,
    the bots will diverge on best moves. But, why am I even
    wasting my time with you half brained "believer" morons
    when I should know better that you neither won't or can't
    consider what I say even as mere hypothetical possibilities...

    MK

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  • From Timothy Chow@21:1/5 to All on Tue Jul 19 09:30:20 2022
    On 7/19/2022 7:25 AM, MK wrote:
    On July 7, 2022 at 7:17:27 PM UTC-6, Tim Chow wrote:

    On 7/4/2022 5:53 PM, MK wrote:

    in the past I had caught and posted many examples of
    Gnubg's making "PR sacrificing" checker decisions
    during the game by looking ahead to upcoming dice rolls.

    You still believe this nonsense?
    [...]
    My comment was meant to be a semi-serious, semi-snide
    explanation, expecting that nobody else would ridicule
    themselves offering explanations.

    Ah, so your answer is no. Some vestige of sanity still remains
    in that brain of yours, fighting to get out.

    ---
    Tim Chow

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  • From MK@21:1/5 to Tim Chow on Fri Jul 22 00:39:48 2022
    On July 19, 2022 at 7:30:23 AM UTC-6, Tim Chow wrote:

    On 7/19/2022 7:25 AM, MK wrote:

    My comment was meant to be a semi-serious, semi-
    snide explanation, expecting that nobody else would
    ridicule themselves offering explanations.

    Ah, so your answer is no. Some vestige of sanity still
    remains in that brain of yours, fighting to get out.

    As typical, you pick one sentence from my post and
    repond to it with onle sentence also. Perhaps your
    brain (however much you have) filters out the rest
    in self-defense. I hope that others may have gotten
    a little more from it than you.

    Why don't we go back to your reply to Axel and do a
    retake. You started your bullshit by saying:

    This is the sort of position that GNU and XG still
    have some trouble with.

    Since you are generalizing from it, can you give some
    other examples of "this sort of position"..?

    And you finished with a rollout by saying:

    Even these settings were yielding pretty high variance,
    but at least the final result is in line with what I would
    expect from general principles (i.e., ND/T).
    .....
    Moves: 4-ply, cube decisions: XG Roller+

    If you had kept going up the ladder, you would have seen
    that unfortuately for you, the D/T comes back at 6-ply.

    So, let's take a more close look at what bots say about it.

    In Gnubg, which Axel was playing against, we see:

    Beginner = ND/T
    Casual Play = ND/T
    Intermediate = ND/T
    Advanced = ND/T
    Expert = D/T **
    World Class = ND/T
    Supremo = ND/T
    Grand Master = D/T **
    4-ply = ND/T

    He didn't say which level he was playing against but it
    is very odd that contradicting decisions are interleaved.

    In XG, which you prefer for some reason, we see:

    1-ply = D/T
    2-ply = D/P !!
    3-ply red = D/T
    3-ply = D/T
    XG Roller = D/T
    4-ply = D/T
    5-ply = D/T
    XG Roller+ = ND/T **
    6-ply = D/T
    7-ply = ND/T **
    XG Roller++ = ND/T **

    Not only contradicting decisions are also interleaved but
    there is also the bonus oddity of D/P at 2-ply.

    I asked for it but Axel didn't post the game record here in
    text format which would have taken only a few seconds
    of copy/paste. I wonder if he was afraid that I could find
    something more to point at in there..?

    You guys' denial of the obvious will only delay it for you
    (unfortunately) but eventually you all will what pieces of
    shit are the gamblegammon bots that you worship...

    MK

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