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Rollout Results at Four Scores

Posted By: Paul Weaver
Date: Monday, 22 February 2016, at 6:03 p.m.

In Response To: DMP 51 (Paul Weaver)

Thanks to Nack for coming up with a variation that appears to be far more interesting that the position I posted. Also, thanks to my friend who emailed me the 15K DMP rollout results of the original position I posted. He said he did not know how to email me the XG file. Requesting that he post the rollout data he sent me, if he knows how and is willing to do it.

I agree with Tim's comment that the margin is so tiny we cannot be sure of the best play. If this is the case, then why bother making this post? I believe it is interesting and instructive to know that double-slot is at least a contender at DMP, with more than a 50% chance of actually being best. I have no way of knowing what play you would have made, but I admit I made the naive beginners' play over the board.

Check out the probability distributions (the % of wins, Gs and BGs of each player) in the rollout data. Notice how they differ according to the score. When losing a BG is consequential, it can seriously reduce your winning chances when you play to avoid losing a BG. I leave it to the reader to guess the GS play.

If your name is not Nack, you may find this comment to be irrelevant, but this position came up in a one-point Nackgammon match between Othello and me. Here is something that is very relevant to those of you not named Nack: You want to improve your checker play in complex positions? Play a lot of Nackgammon and study the XG analysis.

 White is othello score: 0 pip: 125 1 point match pip: 180 score: 0 Blue is peever
XGID=--a-A-D-Ca---B--dcCb-bb-B-:0:0:1:51:0:0:0:1:10
Blue to play 51

1.Rollout118/13 6/5eq: -0.210
 Player:Opponent: 39.51% (G:4.33% B:0.38%)60.49% (G:37.62% B:17.16%) Conf.: ± 0.004 (-0.214...-0.206) - [100.0%]Duration: 42 minutes 15 seconds
2.Rollout18/3 4/3eq: -0.219 (-0.009)
 Player:Opponent: 39.04% (G:5.65% B:0.40%)60.96% (G:31.59% B:11.92%) Conf.: ± 0.003 (-0.222...-0.216) - [0.0%]Duration: 33 minutes 22 seconds
1 5184 Games rolled with Variance Reduction.
Dice Seed: 101
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

 White is othello score: 0 pip: 125 3 point match pip: 180 score: 2 Blue is peever
XGID=--a-A-D-Ca---B--dcCb-bb-B-:0:0:1:51:2:0:0:3:10
Blue to play 51

1.Rollout18/3 4/3eq: -0.753
 Player:Opponent: 34.71% (G:5.01% B:0.48%)65.29% (G:20.24% B:5.78%) Conf.: ± 0.009 (-0.761...-0.744) - [100.0%]Duration: 6 minutes 42 seconds
2.Rollout118/13 6/5eq: -0.855 (-0.103)
 Player:Opponent: 36.67% (G:3.97% B:0.30%)63.33% (G:27.22% B:11.95%) Conf.: ± 0.012 (-0.867...-0.843) - [0.0%]Duration: 8 minutes 27 seconds
1 1296 Games rolled with Variance Reduction.
Dice Seed: 101
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

 White is othello score: 0 pip: 125 Unlimited GameJacoby Beaver pip: 180 score: 0 Blue is peever
XGID=--a-A-D-Ca---B--dcCb-bb-B-:1:-1:1:51:0:0:3:0:10
Blue to play 51

1.Rollout18/3 4/3eq: -0.720
 Player:Opponent: 37.21% (G:6.83% B:0.24%)62.79% (G:24.65% B:2.94%) Conf.: ± 0.015 (-0.734...-0.705) - [99.9%]Duration: 15 minutes 20 seconds
2.Rollout118/13 6/5eq: -0.768 (-0.049)
 Player:Opponent: 37.51% (G:5.17% B:0.21%)62.49% (G:30.87% B:4.63%) Conf.: ± 0.026 (-0.794...-0.742) - [0.1%]Duration: 19 minutes 24 seconds
1 1296 Games rolled with Variance Reduction.
Dice Seed: 101
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

 White is othello score: 1 pip: 125 2 point match Crawford pip: 180 score: 0 Blue is peever
XGID=--a-A-D-Ca---B--dcCb-bb-B-:0:0:1:51:0:1:1:2:10
Blue to play 51

1.Rollout18/3 4/3eq: -0.083
 Player:Opponent: 38.38% (G:7.46% B:0.53%)61.62% (G:33.17% B:11.69%) Conf.: ± 0.008 (-0.091...-0.075) - [99.9%]Duration: 8 minutes 37 seconds
2.Rollout118/13 6/5eq: -0.103 (-0.020)
 Player:Opponent: 39.01% (G:5.86% B:0.42%)60.99% (G:37.76% B:16.48%) Conf.: ± 0.009 (-0.112...-0.093) - [0.1%]Duration: 9 minutes 47 seconds
1 1296 Games rolled with Variance Reduction.
Dice Seed: 101
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

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