• If I said I had a beautiful double, would you hold it against me?

    From pepstein5@gmail.com@21:1/5 to All on Sat Jul 16 14:35:59 2022
    XGID=aBBBBBB-B--aa-a--bbcbb--A-:0:0:1:00:2:2:3:0:10
    X:Daniel O:eXtremeGammon

    Score is X:2 O:2. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O O | | O O O X |
    | O O | | O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | |
    | X | | X X X X X X |
    | O O X | | X X X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 129 X-O: 2-2
    Cube: 1
    X on roll, cube action

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  • From Timothy Chow@21:1/5 to peps...@gmail.com on Sat Jul 16 22:36:45 2022
    On 7/16/2022 5:35 PM, peps...@gmail.com wrote:
    XGID=aBBBBBB-B--aa-a--bbcbb--A-:0:0:1:00:2:2:3:0:10
    X:Daniel O:eXtremeGammon

    Score is X:2 O:2. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O O | | O O O X |
    | O O | | O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | |
    | X | | X X X X X X |
    | O O X | | X X X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 129 X-O: 2-2
    Cube: 1
    X on roll, cube action

    I don't think X has enough spare pips to double here. O's outfield
    blots give me pause, because they increase X's gammon wins, but I
    still don't think it's enough for a double.

    ---
    Tim Chow

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  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Sun Jul 17 02:52:49 2022
    On Sunday, July 17, 2022 at 3:36:51 AM UTC+1, Tim Chow wrote:
    On 7/16/2022 5:35 PM, peps...@gmail.com wrote:
    XGID=aBBBBBB-B--aa-a--bbcbb--A-:0:0:1:00:2:2:3:0:10
    X:Daniel O:eXtremeGammon

    Score is X:2 O:2. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O O | | O O O X |
    | O O | | O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | |
    | X | | X X X X X X |
    | O O X | | X X X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 129 X-O: 2-2
    Cube: 1
    X on roll, cube action
    I don't think X has enough spare pips to double here. O's outfield
    blots give me pause, because they increase X's gammon wins, but I
    still don't think it's enough for a double.

    This could be a (somewhat) rare case where Jacoby is relevant.
    I haven't rolled out the non-Jacoby case.

    Paul

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  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Sun Jul 17 04:14:21 2022
    On Sunday, July 17, 2022 at 3:36:51 AM UTC+1, Tim Chow wrote:
    On 7/16/2022 5:35 PM, peps...@gmail.com wrote:
    XGID=aBBBBBB-B--aa-a--bbcbb--A-:0:0:1:00:2:2:3:0:10
    X:Daniel O:eXtremeGammon

    Score is X:2 O:2. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O O | | O O O X |
    | O O | | O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | |
    | X | | X X X X X X |
    | O O X | | X X X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 129 X-O: 2-2
    Cube: 1
    X on roll, cube action
    I don't think X has enough spare pips to double here. O's outfield
    blots give me pause, because they increase X's gammon wins, but I
    still don't think it's enough for a double.

    ---
    Tim Chow

    Do you see it as an ND/beaver or an ND/T?
    (Try and pretend that you didn't see my follow-up post.)

    Paul

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  • From Timothy Chow@21:1/5 to peps...@gmail.com on Sun Jul 17 19:53:50 2022
    On 7/17/2022 7:14 AM, peps...@gmail.com wrote:
    Do you see it as an ND/beaver or an ND/T?
    (Try and pretend that you didn't see my follow-up post.)

    ND/T. This doesn't look like a Kauder paradox to me.

    ---
    Tim Chow

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  • From pepstein5@gmail.com@21:1/5 to peps...@gmail.com on Mon Jul 18 00:25:22 2022
    On Monday, July 18, 2022 at 8:22:45 AM UTC+1, peps...@gmail.com wrote:
    On Monday, July 18, 2022 at 12:53:53 AM UTC+1, Tim Chow wrote:
    On 7/17/2022 7:14 AM, peps...@gmail.com wrote:
    Do you see it as an ND/beaver or an ND/T?
    (Try and pretend that you didn't see my follow-up post.)
    ND/T. This doesn't look like a Kauder paradox to me.
    Holding is a big blunder. I get only just over 50% wins but approx 60% of the wins are gammons.
    This position has the (somewhat) unusual trait in that you have to double, even
    though you don't have that big an edge.
    I was (wrongly) quite confident in the hold.
    I will post the rollout later -- it's on my other computer.

    Paul

    There are two obvious variantizations -- non-Jacoby or owning the cube.
    These are probably holds but I have difficulties setting up positions (as opposed
    to just exporting positions that I've already met) so I won't be
    doing rollouts for these.

    Paul

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  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Mon Jul 18 00:22:44 2022
    On Monday, July 18, 2022 at 12:53:53 AM UTC+1, Tim Chow wrote:
    On 7/17/2022 7:14 AM, peps...@gmail.com wrote:
    Do you see it as an ND/beaver or an ND/T?
    (Try and pretend that you didn't see my follow-up post.)
    ND/T. This doesn't look like a Kauder paradox to me.

    Holding is a big blunder. I get only just over 50% wins but approx 60% of the wins are gammons.
    This position has the (somewhat) unusual trait in that you have to double, even though you don't have that big an edge.
    I was (wrongly) quite confident in the hold.
    I will post the rollout later -- it's on my other computer.

    Paul

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  • From Timothy Chow@21:1/5 to peps...@gmail.com on Tue Jul 19 00:35:58 2022
    On 7/18/2022 3:25 AM, peps...@gmail.com wrote:
    There are two obvious variantizations -- non-Jacoby or owning the cube.
    These are probably holds but I have difficulties setting up positions (as opposed
    to just exporting positions that I've already met) so I won't be
    doing rollouts for these.

    According to the rollouts below, the non-Jacoby is a borderline D/ND
    and X owning the cube is a clear hold. Very nice position for
    illustrating the differences among these three scenarios!

    ------------------------
    No Jacoby, centered cube
    ------------------------

    XGID=aBBBBBB-B--aa-a--bbcbb--A-:0:0:1:00:0:0:0:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O O | | O O O X |
    | O O | | O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | |
    | X | | X X X X X X |
    | O O X | | X X X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 129 X-O: 0-0
    Cube: 1
    X on roll, cube action

    Analyzed in Rollout
    No double
    Player Winning Chances: 51.91% (G:37.28% B:0.71%)
    Opponent Winning Chances: 48.09% (G:4.52% B:0.14%)
    Double/Take
    Player Winning Chances: 52.08% (G:37.19% B:0.63%)
    Opponent Winning Chances: 47.92% (G:4.53% B:0.14%)

    Cubeless Equities: No Double=+0.372, Double=+0.746

    Cubeful Equities:
    No double: +0.288 (-0.014)
    Double/Take: +0.303
    Double/Pass: +1.000 (+0.697)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 4-ply, cube decisions: XG Roller+
    Search interval: Large
    Confidence No Double: ± 0.008 (+0.280..+0.296)
    Confidence Double: ± 0.015 (+0.288..+0.317)

    eXtreme Gammon Version: 2.19.207.pre-release

    -----------
    X owns cube
    -----------

    XGID=aBBBBBB-B--aa-a--bbcbb--A-:1:1:1:00:0:0:0:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O O | | O O O X |
    | O O | | O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | | +---+
    | X | | X X X X X X | | 2 |
    | O O X | | X X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 129 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action

    Analyzed in Rollout
    No redouble
    Player Winning Chances: 51.65% (G:37.42% B:0.71%)
    Opponent Winning Chances: 48.35% (G:4.60% B:0.13%)
    Redouble/Take
    Player Winning Chances: 52.08% (G:37.19% B:0.63%)
    Opponent Winning Chances: 47.92% (G:4.53% B:0.14%)

    Cubeful Equities:
    No redouble: +0.468
    Redouble/Take: +0.303 (-0.165)
    Redouble/Pass: +1.000 (+0.532)

    Best Cube action: No redouble / Take
    Percentage of wrong pass needed to make the double decision right: 19.2%

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 4-ply, cube decisions: XG Roller+
    Search interval: Large
    Confidence No Double: ± 0.005 (+0.463..+0.473)
    Confidence Double: ± 0.015 (+0.288..+0.317)

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow

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  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Tue Jul 19 00:38:21 2022
    On Tuesday, July 19, 2022 at 5:36:01 AM UTC+1, Tim Chow wrote:
    On 7/18/2022 3:25 AM, peps...@gmail.com wrote:
    There are two obvious variantizations -- non-Jacoby or owning the cube. These are probably holds but I have difficulties setting up positions (as opposed
    to just exporting positions that I've already met) so I won't be
    doing rollouts for these.
    According to the rollouts below, the non-Jacoby is a borderline D/ND
    and X owning the cube is a clear hold. Very nice position for
    illustrating the differences among these three scenarios!

    ------------------------
    No Jacoby, centered cube
    ------------------------

    XGID=aBBBBBB-B--aa-a--bbcbb--A-:0:0:1:00:0:0:0:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O O | | O O O X |
    | O O | | O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | |
    | X | | X X X X X X |
    | O O X | | X X X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 129 X-O: 0-0
    Cube: 1
    X on roll, cube action
    Analyzed in Rollout
    No double
    Player Winning Chances: 51.91% (G:37.28% B:0.71%)
    Opponent Winning Chances: 48.09% (G:4.52% B:0.14%)
    Double/Take
    Player Winning Chances: 52.08% (G:37.19% B:0.63%)
    Opponent Winning Chances: 47.92% (G:4.53% B:0.14%)

    Cubeless Equities: No Double=+0.372, Double=+0.746

    Cubeful Equities:
    No double: +0.288 (-0.014)
    Double/Take: +0.303
    Double/Pass: +1.000 (+0.697)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 4-ply, cube decisions: XG Roller+
    Search interval: Large
    Confidence No Double: ± 0.008 (+0.280..+0.296)
    Confidence Double: ± 0.015 (+0.288..+0.317)

    eXtreme Gammon Version: 2.19.207.pre-release

    -----------
    X owns cube
    -----------

    XGID=aBBBBBB-B--aa-a--bbcbb--A-:1:1:1:00:0:0:0:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O O | | O O O X |
    | O O | | O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | | +---+
    | X | | X X X X X X | | 2 |
    | O O X | | X X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 129 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action
    Analyzed in Rollout
    No redouble
    Player Winning Chances: 51.65% (G:37.42% B:0.71%)
    Opponent Winning Chances: 48.35% (G:4.60% B:0.13%)
    Redouble/Take
    Player Winning Chances: 52.08% (G:37.19% B:0.63%)
    Opponent Winning Chances: 47.92% (G:4.53% B:0.14%)

    Cubeful Equities:
    No redouble: +0.468
    Redouble/Take: +0.303 (-0.165)
    Redouble/Pass: +1.000 (+0.532)

    Best Cube action: No redouble / Take
    Percentage of wrong pass needed to make the double decision right: 19.2%

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 4-ply, cube decisions: XG Roller+
    Search interval: Large
    Confidence No Double: ± 0.005 (+0.463..+0.473)
    Confidence Double: ± 0.015 (+0.288..+0.317)

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow
    Glad you liked it. Time for me to follow on with the original rollout. Analyzed in Rollout
    No double
    Player Winning Chances: 51.56% (G:35.79% B:0.66%)
    Opponent Winning Chances: 48.44% (G:4.44% B:0.12%)
    Double/Take
    Player Winning Chances: 52.13% (G:37.44% B:0.66%)
    Opponent Winning Chances: 47.87% (G:4.52% B:0.12%)

    Cubeless Equities: No Double=+0.350, Double=+0.754

    Cubeful Equities:
    No double: +0.185 (-0.123)
    Double/Take: +0.308
    Double/Pass: +1.000 (+0.692)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.008 (+0.177..+0.194)
    Confidence Double: ± 0.019 (+0.289..+0.326)

    Double Decision confidence: 100.0%
    Take Decision confidence: 100.0%

    Duration: 20 minutes 09 seconds

    eXtreme Gammon Version: 2.10

    Now, let's check for consistency between all three rollouts.
    First look at the hold situation. Non-Jacoby is clearly better for
    the favourite than mine but clearly not as good as actually holding
    the cube. So, for holding, we expect original equity < non-Jacoby equity < own cube equity.
    And indeed we get 0.185 < 0.288 < 0.468.
    For doubling, we expect all equities to be the same.
    Tim gets 0.303 and I get 0.308. This is a small discrepancy which is easily explained
    by the different settings and the confidence bounds.

    Paul

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