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  • This is not an anti-conservation argument

    From [email protected]@21:1/5 to All on Tue Jan 25 03:45:33 2022
    I totally agree with all moves to preserve rare species. However, I do think that
    beavers might be more frequent than is commonly supposed.
    I thought I played an excellent game against XG but, in fact, my PR was around 9.0
    My mistake? The only mistake taking me out of world-class territory
    was that I didn't think to beaver XG! XG thought that my not beavering
    was a greater mistake than its own double.
    XG surprised me a lot by doubling the position. I didn't even consider
    the beaver, but was very sure of the take. My thinking was that I had
    made a checkerplay mistake to lead to this position but XG didn't think
    so.

    Paul

    XGID=aBABC-BAb---AA-B--bbcbab--:0:0:-1:00:0:0:3:0:10
    X:eXtremeGammon O:Daniel

    Score is X:0 O:0. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O X O | | O O O O O |
    | X | | O O O O |
    | | | O |
    | | | |
    | | X | |
    | |BAR| |
    | | | |
    | | | |
    | | | X |
    | O X | | X X X X |
    | O O X | | X X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 115 O: 96 X-O: 0-0
    Cube: 1
    X on roll, cube action

    Analyzed in XG Roller+
    Player Winning Chances: 49.75% (G:24.66% B:2.25%)
    Opponent Winning Chances: 50.25% (G:14.32% B:0.30%)

    Cubeless Equities: No Double=+0.118, Double=+0.241

    Cubeful Equities:
    No double: -0.183
    Double/Beaver: -0.451 (-0.268)
    Double/Pass: +1.000 (+1.183)

    Best Cube action: No double / Beaver
    Percentage of wrong pass needed to make the double decision right: 15.6%

    eXtreme Gammon Version: 2.10

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to [email protected] on Tue Jan 25 08:48:42 2022
    On 1/25/2022 6:45 AM, [email protected] wrote:
    I totally agree with all moves to preserve rare species. However, I do think that
    beavers might be more frequent than is commonly supposed.

    They may also be more common than is frequently supposed.

    I thought I played an excellent game against XG but, in fact, my PR was around 9.0
    My mistake? The only mistake taking me out of world-class territory
    was that I didn't think to beaver XG! XG thought that my not beavering
    was a greater mistake than its own double.

    Interesting. Below is a variant that XG 3-ply thinks is a simple take
    but that a rollout deems to be a beaver.

    XGID=aB-CBABAb---AA-B--bbcbab--:0:0:-1:00:0:0:3:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    | X X O | | O O O O O |
    | X O | | O O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | X |
    | O | | X X X X |
    | X O X | | X X X X X |
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    Pip count X: 98 O: 115 X-O: 0-0
    Cube: 1
    O on roll, cube action

    Analyzed in Rollout
    No double
    Player Winning Chances: 52.08% (G:27.77% B:2.31%)
    Opponent Winning Chances: 47.92% (G:15.27% B:0.30%)
    Double/Take
    Player Winning Chances: 52.24% (G:29.07% B:2.99%)
    Opponent Winning Chances: 47.76% (G:15.37% B:0.38%)

    Cubeless Equities: No Double=+0.187, Double=+0.416

    Cubeful Equities:
    No double: -0.178
    Double/Beaver: -0.198 (-0.020)
    Double/Pass: +1.000 (+1.178)

    Best Cube action: No double / Beaver
    Percentage of wrong pass needed to make the double decision right: 1.7%

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.010 (-0.188..-0.168)
    Confidence Double: ± 0.042 (-0.241..-0.156)

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From [email protected]@21:1/5 to Tim Chow on Tue Jan 25 08:18:45 2022
    On Tuesday, January 25, 2022 at 1:48:46 PM UTC, Tim Chow wrote:
    On 1/25/2022 6:45 AM, [email protected] wrote:
    I totally agree with all moves to preserve rare species. However, I do think that
    beavers might be more frequent than is commonly supposed.
    They may also be more common than is frequently supposed.
    I thought I played an excellent game against XG but, in fact, my PR was around 9.0
    My mistake? The only mistake taking me out of world-class territory
    was that I didn't think to beaver XG! XG thought that my not beavering
    was a greater mistake than its own double.
    Interesting. Below is a variant that XG 3-ply thinks is a simple take
    but that a rollout deems to be a beaver.

    XGID=aB-CBABAb---AA-B--bbcbab--:0:0:-1:00:0:0:3:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver +12-11-10--9--8--7-------6--5--4--3--2--1-+
    | X X O | | O O O O O |
    | X O | | O O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | X |
    | O | | X X X X |
    | X O X | | X X X X X |
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    Pip count X: 98 O: 115 X-O: 0-0
    Cube: 1
    O on roll, cube action

    Analyzed in Rollout
    No double
    Player Winning Chances: 52.08% (G:27.77% B:2.31%)
    Opponent Winning Chances: 47.92% (G:15.27% B:0.30%)
    Double/Take
    Player Winning Chances: 52.24% (G:29.07% B:2.99%)
    Opponent Winning Chances: 47.76% (G:15.37% B:0.38%)

    Cubeless Equities: No Double=+0.187, Double=+0.416

    Cubeful Equities:
    No double: -0.178
    Double/Beaver: -0.198 (-0.020)
    Double/Pass: +1.000 (+1.178)
    Best Cube action: No double / Beaver
    Percentage of wrong pass needed to make the double decision right: 1.7%

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.010 (-0.188..-0.168)
    Confidence Double: ± 0.042 (-0.241..-0.156)

    eXtreme Gammon Version: 2.19.207.pre-release

    As always, you prove yourself a major expert in variantization, and I think we've uncovered the nub of the matter.
    In your variantization, a double is only a small error -- 0.02. It's close to a Kauder paradox position -- double/beaver is close
    to correct. The double is a tragic blunder (by XG) in my situation, though.

    Paul

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