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My matches in New York Metropolitan Open 2014

Posted By: Igor
Date: Saturday, 18 January 2014, at 1:38 a.m.

In Response To: My matches in New York Metropolitan Open 2014 (Henrik Bukkjaer)

But looking further down in the same match, game 3, you decide to take when doubled in a dubious 2-5 backgame. (at this point, Jason have missed 7 cubes in that particular game). Score is 6-0/9 in your favor, and you risk a gammon at the rate of about 20%.

The position is a proper double, and a pass according to XG. It's by no means a big pass, only a 0,027 error, but if you were going to adjust anything in your game from low PR towards winning - this is exactly the place to do so (in my eyes).

I have done a few rollouts of backgame cube actions with XGR+ checker plays and cube decisions, search interval huge. What I noticed is that XG evaluation of backgame cube decisions is way off. It grossly undervalues chances of the backgame player. Perhaps due to its known weakness in containment game.

I have not done rollouts for that particular game, but I believe they might turn all those "missed cubes" by Jason into proper non-doubles and Mochy's "small pass" into a huge take.

Here is a sample of what I did some time ago to compare different rollout settings. Anything lower than XGR+/XGR+ is quite a bit off. Notice that changing search interval for 4-ply checker play has zero effect -- meaning XG does not play 4-ply much better than 3-ply for backgames.

 White is Player 2 score: 0 pip: 151 Unlimited GameJacoby Beaver pip: 66 score: 0 Blue is Player 1
XGID=-bbDDDC-----------cbbbb---:0:0:1:00:0:0:3:0:10
Blue on roll, cube action?

 Analyzed in XG Roller++ No double Double/Take Player Winning Chances: 64.90% (G:37.58% B:8.07%) 65.91% (G:38.04% B:8.04%) Opponent Winning Chances: 35.10% (G:0.00% B:0.00%) 34.09% (G:0.00% B:0.00%) Cubeless Equities +0.755 +1.558 Cubeful Equities No double: +1.000 Double/Take: +1.306 (+0.306) Double/Pass: +1.000 Best Cube action: Double / Pass

eXtreme Gammon Version: 2.10

 White is Player 2 score: 0 pip: 151 Unlimited GameJacoby Beaver pip: 66 score: 0 Blue is Player 1
XGID=-bbDDDC-----------cbbbb---:0:0:1:00:0:0:3:0:10
Blue on roll, cube action?

 Analyzed in Rollout No double Double/Take Player Winning Chances: 64.76% (G:37.10% B:8.00%) 64.72% (G:37.24% B:8.31%) Opponent Winning Chances: 35.24% (G:0.00% B:0.00%) 35.28% (G:0.00% B:0.00%) Cubeless Equities +0.746 +1.500 Cubeful Equities No double: +0.970 (-0.030) ±0.012 (+0.958..+0.981) Double/Take: +1.176 (+0.176) ±0.025 (+1.151..+1.201) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.Dice Seed: 31641692Moves: 3-ply, cube decisions: XG Roller Double Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 1 minute 45 seconds

eXtreme Gammon Version: 2.10

 White is Player 2 score: 0 pip: 151 Unlimited GameJacoby Beaver pip: 66 score: 0 Blue is Player 1
XGID=-bbDDDC-----------cbbbb---:0:0:1:00:0:0:3:0:10
Blue on roll, cube action?

 Analyzed in Rollout No double Double/Take Player Winning Chances: 64.48% (G:37.02% B:7.87%) 63.79% (G:37.00% B:8.06%) Opponent Winning Chances: 35.52% (G:0.00% B:0.00%) 36.21% (G:0.00% B:0.00%) Cubeless Equities +0.739 +1.453 Cubeful Equities No double: +0.968 (-0.032) ±0.006 (+0.962..+0.975) Double/Take: +1.121 (+0.121) ±0.019 (+1.102..+1.140) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.Dice Seed: 31641692Moves: 4-ply, cube decisions: XG Roller+ Double Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 19 minutes 49 seconds

eXtreme Gammon Version: 2.10

 White is Player 2 score: 0 pip: 151 Unlimited GameJacoby Beaver pip: 66 score: 0 Blue is Player 1
XGID=-bbDDDC-----------cbbbb---:0:0:1:00:0:0:3:0:10
Blue on roll, cube action?

 Analyzed in Rollout No double Double/Take Player Winning Chances: 64.48% (G:37.02% B:7.87%) 63.71% (G:36.99% B:8.05%) Opponent Winning Chances: 35.52% (G:0.00% B:0.00%) 36.29% (G:0.00% B:0.00%) Cubeless Equities +0.739 +1.449 Cubeful Equities No double: +0.968 (-0.032) ±0.006 (+0.962..+0.975) Double/Take: +1.117 (+0.117) ±0.019 (+1.099..+1.136) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.Dice Seed: 31641692Moves: 4-ply, cube decisions: XG Roller+Search interval: Large Double Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 21 minutes 58 seconds

eXtreme Gammon Version: 2.10

 White is Player 2 score: 0 pip: 151 Unlimited GameJacoby Beaver pip: 66 score: 0 Blue is Player 1
XGID=-bbDDDC-----------cbbbb---:0:0:1:00:0:0:3:0:10
Blue on roll, cube action?

 Analyzed in Rollout No double Double/Take Player Winning Chances: 64.48% (G:37.02% B:7.87%) 63.73% (G:37.01% B:8.04%) Opponent Winning Chances: 35.52% (G:0.00% B:0.00%) 36.27% (G:0.00% B:0.00%) Cubeless Equities +0.739 +1.450 Cubeful Equities No double: +0.968 (-0.032) ±0.006 (+0.962..+0.975) Double/Take: +1.121 (+0.121) ±0.019 (+1.102..+1.139) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.Dice Seed: 31641692Moves: 4-ply, cube decisions: XG Roller+Search interval: Huge Double Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 24 minutes 24 seconds

eXtreme Gammon Version: 2.10

 White is Player 2 score: 0 pip: 151 Unlimited GameJacoby Beaver pip: 66 score: 0 Blue is Player 1
XGID=-bbDDDC-----------cbbbb---:0:0:1:00:0:0:3:0:10
Blue on roll, cube action?

 Analyzed in Rollout No double Double/Take Player Winning Chances: 64.21% (G:36.84% B:7.73%) 63.70% (G:36.79% B:7.92%) Opponent Winning Chances: 35.79% (G:0.00% B:0.00%) 36.30% (G:0.00% B:0.00%) Cubeless Equities +0.730 +1.442 Cubeful Equities No double: +0.967 (-0.033) ±0.007 (+0.960..+0.974) Double/Take: +1.103 (+0.103) ±0.019 (+1.084..+1.122) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.Dice Seed: 31641692Moves and cube decisions: XG Roller+ Double Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 1 hour 31 minutes

eXtreme Gammon Version: 2.10

 White is Player 2 score: 0 pip: 151 Unlimited GameJacoby Beaver pip: 66 score: 0 Blue is Player 1
XGID=-bbDDDC-----------cbbbb---:0:0:1:00:0:0:3:0:10
Blue on roll, cube action?

 Analyzed in Rollout No double Double/Take Player Winning Chances: 63.93% (G:36.65% B:7.64%) 63.65% (G:36.84% B:7.88%) Opponent Winning Chances: 36.07% (G:0.00% B:0.00%) 36.35% (G:0.00% B:0.00%) Cubeless Equities +0.721 +1.440 Cubeful Equities No double: +0.965 (-0.035) ±0.007 (+0.958..+0.972) Double/Take: +1.099 (+0.099) ±0.020 (+1.079..+1.119) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.Dice Seed: 31641692Moves and cube decisions: XG Roller+Search interval: Large Double Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 1 hour 53 minutes

eXtreme Gammon Version: 2.10

 White is Player 2 score: 0 pip: 151 Unlimited GameJacoby Beaver pip: 66 score: 0 Blue is Player 1
XGID=-bbDDDC-----------cbbbb---:0:0:1:00:0:0:3:0:10
Blue on roll, cube action?

 Analyzed in Rollout No double Double/Take Player Winning Chances: 63.96% (G:36.66% B:7.64%) 63.60% (G:36.63% B:7.92%) Opponent Winning Chances: 36.04% (G:0.00% B:0.00%) 36.40% (G:0.00% B:0.00%) Cubeless Equities +0.722 +1.435 Cubeful Equities No double: +0.957 (-0.043) ±0.009 (+0.948..+0.966) Double/Take: +1.094 (+0.094) ±0.021 (+1.073..+1.116) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.Dice Seed: 24617919Moves and cube decisions: XG Roller+Search interval: Huge Double Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 2 hours 17 minutes

eXtreme Gammon Version: 2.10

About 0.2 in relative equity difference regarding the pass decision between XGR++ evaluation and XGR+/XGR+ rollout.

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