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501 Essential Backgammon Problems #40 -- RO + Variant

Posted By: Igor
Date: Monday, 26 August 2013, at 1:43 p.m.

In Response To: 501 Essential Backgammon Problems #40 (Igor)

I have nothing to add to Mike's excellent analysis.

		White is Player 2 score: 0 pip: 159 Unlimited Game Jacoby pip: 160 score: 0 Blue is Player 1
XGID=-----bE-D--AeC---c-e----B-:0:0:1:61:0:0:1:0:10
Blue to play 61

1.	Rollout1	11/4	eq: -0.284
	Player: Opponent: 43.60% (G:8.37% B:0.29%) 56.40% (G:14.25% B:0.47%) Conf.: ± 0.003 (-0.287...-0.281) - [100.0%] Duration: 2 hours 53 minutes
2.	Rollout1	24/18 11/10	eq: -0.293 (-0.008)
	Player: Opponent: 43.22% (G:8.72% B:0.32%) 56.78% (G:14.32% B:0.60%) Conf.: ± 0.003 (-0.296...-0.289) - [0.0%] Duration: 3 hours 08 minutes
3.	Rollout2	13/7 8/7	eq: -0.301 (-0.016)
	Player: Opponent: 43.05% (G:8.93% B:0.33%) 56.95% (G:14.27% B:0.58%) Conf.: ± 0.005 (-0.306...-0.295) - [0.0%] Duration: 1 hour 09 minutes
4.	Rollout2	24/23 24/18	eq: -0.304 (-0.019)
	Player: Opponent: 43.19% (G:7.65% B:0.29%) 56.81% (G:14.54% B:0.54%) Conf.: ± 0.005 (-0.309...-0.299) - [0.0%] Duration: 1 hour 12 minutes
5.	Rollout3	24/18 8/7	eq: -0.320 (-0.036)
	Player: Opponent: 43.10% (G:8.72% B:0.34%) 56.90% (G:16.64% B:0.85%) Conf.: ± 0.008 (-0.328...-0.312) - [0.0%] Duration: 36 minutes 47 seconds
1 25920 Games rolled with Variance Reduction. Dice Seed: 18260878 Moves: 3-ply, cube decisions: XG Roller 2 10368 Games rolled with Variance Reduction. Dice Seed: 18260878 Moves: 3-ply, cube decisions: XG Roller 3 5184 Games rolled with Variance Reduction. Dice Seed: 18260878 Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

Here is a variant to show that (non-)stripping the midpoint is what makes the difference.

		White is Player 2 score: 0 pip: 159 Unlimited Game Jacoby pip: 165 score: 0 Blue is Player 1
XGID=-----bE-C--AeD---c-e----B-:0:0:1:61:0:0:1:0:10
Blue to play 61

1.	Rollout1	13/7 8/7	eq: -0.317
	Player: Opponent: 42.87% (G:8.32% B:0.31%) 57.13% (G:14.85% B:0.59%) Conf.: ± 0.003 (-0.321...-0.314) - [100.0%] Duration: 3 hours 00 minute
2.	Rollout1	11/4	eq: -0.331 (-0.014)
	Player: Opponent: 42.51% (G:7.81% B:0.28%) 57.49% (G:14.78% B:0.50%) Conf.: ± 0.003 (-0.334...-0.328) - [0.0%] Duration: 2 hours 55 minutes
3.	Rollout2	24/23 24/18	eq: -0.337 (-0.019)
	Player: Opponent: 42.43% (G:7.17% B:0.28%) 57.57% (G:15.27% B:0.60%) Conf.: ± 0.007 (-0.344...-0.329) - [0.0%] Duration: 36 minutes 28 seconds
4.	Rollout2	24/18 11/10	eq: -0.338 (-0.021)
	Player: Opponent: 42.33% (G:8.40% B:0.33%) 57.67% (G:15.38% B:0.63%) Conf.: ± 0.007 (-0.346...-0.331) - [0.0%] Duration: 38 minutes 16 seconds
5.	Rollout2	24/23 13/7	eq: -0.364 (-0.046)
	Player: Opponent: 41.69% (G:9.14% B:0.34%) 58.31% (G:16.10% B:0.77%) Conf.: ± 0.008 (-0.371...-0.356) - [0.0%] Duration: 38 minutes 07 seconds
1 25920 Games rolled with Variance Reduction. Dice Seed: 77695334 Moves: 3-ply, cube decisions: XG Roller 2 5184 Games rolled with Variance Reduction. Dice Seed: 67453503 Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

Messages In This Thread

• 501 Essential Backgammon Problems #40
  Igor -- Friday, 23 August 2013, at 10:27 p.m.
  • 501 Essential Backgammon Problems #40
    Taper_Mike -- Saturday, 24 August 2013, at 7:06 a.m.
    • 501 Essential Backgammon Problems #40
      W Womack -- Sunday, 25 August 2013, at 8:56 p.m.
      • 501 Essential Backgammon Problems #40
        W Womack -- Sunday, 25 August 2013, at 8:58 p.m.
        • 501 Essential Backgammon Problems #40
          Taper_Mike -- Monday, 26 August 2013, at 6:11 a.m.
  • 501 Essential Backgammon Problems #40 -- RO + Variant
    Igor -- Monday, 26 August 2013, at 1:43 p.m.
    • 64R-52H-54@-61 — Unlimited Games — 2-ply GnuBg Trunc
      Taper_Mike -- Wednesday, 28 August 2013, at 7:49 a.m.
  • 501 #40 ROs (52D-22@-61)
    Stick -- Friday, 30 August 2013, at 8:07 a.m.