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Rollouts

Posted By: Stick
Date: Saturday, 19 December 2009, at 3:26 p.m.

In Response To: Prime Time (Stick)

First, the actual position posted. (AtS) As you can see, there's play A and then there's everything else. I only briefly considered 23, 9. It seemed like a weak trash play to me and I only added it to the rollout after Rich and MCG mentioned it. I found a much better play in 10, 9. I took a fair amount of time deciding between my final play and 7, 7. I eventually decided I didn't like how often I get blown off the board with 7, 7 and went with 10, 9.

Where was my thinking flawed? I didn't take the entire problem into consideration. If I had I would have realized many details such as my opponents backgammon wins being worthless. More important is my opponents gammon value which is clearly decreased from money value at this score. I think that's the biggest kicker to this problem. Lastly, as some have mentioned, at this score my rewhips are fast and furious. I haven't completely investigated how often I get to reship after the next sequence and where my opponent stands on the T/P decision differing from money play, but I suspect there is a real difference.

Below are various rollouts, AtS and money, showing my OtB play to be reasonable for money and donkey AtS. I had blinders on to my opponent's gv and made the sissy play.

The score (after 9 games) is: Stick 5, zillaBoy 8 (match to 11 points)

Stick	133
zillaBoy	99
Position ID: 7PaGAAjY5qoCIA Match ID: AQFmAVAAQAAA

#		Ply	Move	Equity
	1	R	11/7 8/7	+0.1727
			0.4424 0.0651 0.0077 - 0.5576 0.4172 0.0909 -0.1389 +0.1727 0.0070 0.0039 0.0037 - 0.0070 0.0137 0.0217 0.0212 0.0276
			Full cubeful rollout with var.redn.
			108 games, Mersenne Twister dice gen. with seed 839451541 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	24/23 13/9	+0.0225 ( -0.1502)
			0.3959 0.0672 0.0042 - 0.6041 0.4574 0.0198 -0.2054 +0.0225 0.0072 0.0048 0.0012 - 0.0072 0.0227 0.0096 0.0206 0.0275
			Full cubeful rollout with var.redn.
			108 games, Mersenne Twister dice gen. with seed 839451541 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
•	3	R	13/9 11/10	-0.0793 ( -0.2520)
			0.3671 0.0666 0.0152 - 0.6329 0.3771 0.0243 -0.2741 -0.0793 0.0076 0.0060 0.0091 - 0.0076 0.0215 0.0071 0.0196 0.0293
			Full cubeful rollout with var.redn.
			108 games, Mersenne Twister dice gen. with seed 839451541 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

---

gnubg	133
user	99
Position ID: 7PaGAAjY5qoCIA Match ID: AQEGAAAAAAAA

#		Ply	Move	Equity
•	1	R	13/9 11/10	-0.3482
			0.3660 0.0631 0.0031 - 0.6340 0.3000 0.0038 -0.5056 -0.3482 0.0012 0.0008 0.0002 - 0.0012 0.0016 0.0003 0.0030 0.0043
			Full cubeful rollout with var.redn.
			2776 games, Mersenne Twister dice gen. with seed 838868834 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	11/7 8/7	-0.3496 ( -0.0015)
			0.4436 0.0607 0.0023 - 0.5564 0.4075 0.0404 -0.4978 -0.3496 0.0013 0.0009 0.0001 - 0.0013 0.0018 0.0011 0.0040 0.0051
			Full cubeful rollout with var.redn.
			2776 games, Mersenne Twister dice gen. with seed 838868834 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	3	R	24/23 13/9	-0.4008 ( -0.0526)
			0.3788 0.0669 0.0026 - 0.6212 0.3720 0.0090 -0.5539 -0.4008 0.0052 0.0024 0.0008 - 0.0052 0.0066 0.0032 0.0134 0.0173
			Full cubeful rollout with var.redn.
			148 games, Mersenne Twister dice gen. with seed 838868834 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

---

	is Player 2 score: 0 pip: 99 Money session Jacoby Beaver pip: 133 score: 0 is Player 1
XGID=---aBBB-CAAAAAa---bdbcb-A-:1:1:1:41:0:0:3:0:10
to play 41

1.	Rollout1	11/7 8/7	eq: -0.339
	Player: Opponent: 44.32% (G:6.97% B:0.32%) 55.68% (G:40.51% B:4.65%) Conf: ± 0.014 (-0.353...-0.325) Duration: 3 hours 30 minutes 08 seconds
2.	Rollout2	13/9 11/10	eq: -0.346 (-0.008)
	Player: Opponent: 36.76% (G:6.12% B:0.40%) 63.24% (G:29.97% B:0.42%) Conf: ± 0.018 (-0.364...-0.328) Duration: 3 hours 17 minutes 52 seconds
1 325 Games rolled with Variance Reduction. Dice Seed: 1296 Moves and cube decisions: 5 ply

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