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64S22E44
Posted By: Maik Stiebler
Date: Friday, 29 August 2014, at 2:12 p.m.
In Response To: 64S22E44 (David Presser)
I wondered why truncated rollouts / XGR++ differ from full rollouts by so much. I think the key is the evaluation of the running play after the opponent misses, e.g. with a 61. The full rollout in the left diagram differs from the truncated one in the right diagram by more than 0.060.
White is Player 1
score: 0
pip: 141Unlimited Game
Jacoby Beaverpip: 159
score: 0
Blue is Player 2XGID=bECBeCAAccb:0:0:1:61:0:0:3:0:10 Blue to play 61
1. Rollout^{1} 13/7 8/7 eq: 0.551
Player:
Opponent:34.63% (G:5.21% B:0.15%)
65.37% (G:4.69% B:0.17%)Conf.: ± 0.012 (0.563...0.539)
Duration: 9 minutes 22 seconds^{1} 1296 Games rolled with Variance Reduction.
Dice Seed: 68613879
Moves and cube decisions: 3plyeXtreme Gammon Version: 2.10
White is Player 1
score: 0
pip: 141Unlimited Game
Jacoby Beaverpip: 159
score: 0
Blue is Player 2XGID=bECBeCAAccb:0:0:1:61:0:0:3:0:10 Blue to play 61
1. Rollout^{1} 13/7 8/7 eq: 0.487
Player:
Opponent:34.86% (G:4.76% B:0.12%)
65.14% (G:4.80% B:0.13%)Conf.: ± 0.004 (0.490...0.483)
Duration: 1 minute 32 seconds^{1} Truncated at 4 moves using 3ply.
1296 Games rolled with Variance Reduction.
Dice Seed: 68613835
Moves and cube decisions: 3plyeXtreme Gammon Version: 2.10
However, in the following cubeless rollouts, full and truncated agree. So I guess XG either underestimates the amount of cube vig against the holding game, or it misplays the cube for the holding game player in the full rollout.
White is Player 1
score: 0
pip: 141Unlimited Game pip: 159
score: 0
Blue is Player 2XGID=bECBeCAAccb:0:0:1:61:0:0:0:0:0 Blue to play 61
1. Rollout^{1} 13/7 8/7 eq: 0.308
Player:
Opponent:34.49% (G:5.25% B:0.15%)
65.51% (G:5.01% B:0.19%)Conf.: ± 0.005 (0.313...0.303)
Duration: 9 minutes 43 seconds^{1} 1296 Games rolled with Variance Reduction.
Dice Seed: 68613838
Moves and cube decisions: 3plyeXtreme Gammon Version: 2.10
White is Player 1
score: 0
pip: 141Unlimited Game pip: 159
score: 0
Blue is Player 2XGID=bECBeCAAccb:0:0:1:61:0:0:0:0:0 Blue to play 61
1. Rollout^{1} 13/7 8/7 eq: 0.306
Player:
Opponent:34.73% (G:4.66% B:0.12%)
65.27% (G:4.68% B:0.12%)Conf.: ± 0.001 (0.307...0.305)
Duration: 1 minute 07 seconds^{1} Truncated at 4 moves using 3ply.
1296 Games rolled with Variance Reduction.
Dice Seed: 68613832
Moves and cube decisions: 3plyeXtreme Gammon Version: 2.10

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