Forwards or backwards? Further analysis

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Forwards or backwards? Further analysis

Posted By: Timothy Chow
Date: Wednesday, 22 February 2012, at 12:21 a.m.

In Response To: Forwards or backwards? (Timothy Chow)

I decided to study this position a little more. First I looked at whether changing the location of White's other blot made much difference.

White is Player 1

score: 0
pip: 105

Money session
Jacoby Beaver

pip: 176
score: 0

Blue is Player 2

XGID=----B-B-D--aaBA-bbbcBbBb--:1:1:1:54:0:0:3:0:10
Blue to play 54

1. Rollout¹ 20/11* eq: -0.191
Player:
Opponent: 41.42% (G:7.89% B:0.34%)
58.58% (G:27.38% B:0.95%) Conf: ą 0.012 (-0.203...-0.179)
Duration: 7 hours 08 minutes
2. Rollout¹ 14/5 eq: -0.242 (-0.051)
Player:
Opponent: 37.19% (G:5.14% B:0.19%)
62.81% (G:17.50% B:0.25%) Conf: ą 0.009 (-0.251...-0.233)
Duration: 5 hours 44 minutes

¹ 2258 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply

eXtreme Gammon Version: 1.21

White is Player 1

score: 0
pip: 99

Money session
Jacoby Beaver

pip: 176
score: 0

Blue is Player 2

XGID=----B-B-D--a-BA-bbccBbBb--:1:1:1:54:0:0:3:0:10
Blue to play 54

1. Rollout¹ 20/11* eq: -0.223
Player:
Opponent: 41.11% (G:7.89% B:0.34%)
58.89% (G:29.36% B:1.20%) Conf: ą 0.013 (-0.236...-0.210)
Duration: 4 hours 38 minutes
2. Rollout¹ 14/5 eq: -0.303 (-0.081)
Player:
Opponent: 36.12% (G:4.56% B:0.15%)
63.88% (G:20.48% B:0.24%) Conf: ą 0.009 (-0.312...-0.294)
Duration: 3 hours 53 minutes

¹ 1728 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply

eXtreme Gammon Version: 1.21

The absolute equities changed a little but XG still preferred hitting. Next I varied the position to make it harder for Blue to hop all his back checkers over White's prime. I expected that going backwards would then be "forced."

White is Player 1

score: 0
pip: 110

Money session
Jacoby Beaver

pip: 190
score: 0

Blue is Player 2

XGID=----B-BaC--a-BA-bbbcBbCb--:1:1:1:54:0:0:3:0:10
Blue to play 54

1. Rollout¹ 14/5 eq: -0.189
Player:
Opponent: 41.03% (G:6.59% B:0.24%)
58.97% (G:24.50% B:0.37%) Conf: ą 0.011 (-0.200...-0.178)
Duration: 4 hours 34 minutes
2. Rollout¹ 20/11* eq: -0.196 (-0.007)
Player:
Opponent: 42.10% (G:9.79% B:0.47%)
57.90% (G:31.29% B:1.52%) Conf: ą 0.016 (-0.212...-0.180)
Duration: 5 hours 10 minutes

¹ 2227 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply

eXtreme Gammon Version: 1.21

White is Player 1

score: 0
pip: 112

Money session
Jacoby Beaver

pip: 178
score: 0

Blue is Player 2

XGID=----B-BaD--a-BA-bbbcBbbB--:1:1:1:54:0:0:3:0:10
Blue to play 54

1. Rollout¹ 14/5 eq: -0.259
Player:
Opponent: 37.19% (G:5.04% B:0.19%)
62.81% (G:20.36% B:0.86%) Conf: ą 0.010 (-0.269...-0.249)
Duration: 7 hours 55 minutes
2. Rollout¹ 20/11* eq: -0.287 (-0.028)
Player:
Opponent: 38.99% (G:8.01% B:0.40%)
61.01% (G:29.94% B:2.14%) Conf: ą 0.013 (-0.300...-0.274)
Duration: 10 hours 01 minute

¹ 2592 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply

eXtreme Gammon Version: 1.21

White is Player 1

score: 0
pip: 109

Money session
Jacoby Beaver

pip: 178
score: 0

Blue is Player 2

XGID=----B-B-Da--aBA-bbbcbBBb--:1:1:1:63:0:0:3:0:10
Blue to play 63

1. Rollout¹ 14/5 eq: -0.167
Player:
Opponent: 40.58% (G:6.19% B:0.25%)
59.42% (G:19.60% B:0.40%) Conf: ą 0.012 (-0.179...-0.155)
Duration: 3 hours 43 minutes
2. Rollout¹ 21/12* eq: -0.303 (-0.136)
Player:
Opponent: 38.52% (G:7.97% B:0.39%)
61.48% (G:31.41% B:1.25%) Conf: ą 0.015 (-0.318...-0.288)
Duration: 4 hours 51 minutes

¹ 1548 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply

eXtreme Gammon Version: 1.21

Sure enough, that made a difference. Finally, I looked at varying the state of Blue's board. This turned out to make more difference than I expected.

White is Player 1

score: 0
pip: 110

Money session
Jacoby Beaver

pip: 174
score: 0

Blue is Player 2

XGID=---B--BaD--a-BA-bbbcBbBb--:1:1:1:54:0:0:3:0:10
Blue to play 54

1. Rollout¹ 14/9 8/4 eq: -0.217
Player:
Opponent: 38.55% (G:6.17% B:0.22%)
61.45% (G:19.99% B:0.40%) Conf: ą 0.010 (-0.227...-0.207)
Duration: 6 hours 18 minutes
2. Rollout¹ 14/5 eq: -0.224 (-0.007)
Player:
Opponent: 37.34% (G:6.00% B:0.22%)
62.66% (G:17.31% B:0.27%) Conf: ą 0.009 (-0.233...-0.215)
Duration: 4 hours 59 minutes
3. Rollout¹ 20/11* eq: -0.226 (-0.009)
Player:
Opponent: 40.01% (G:9.09% B:0.49%)
59.99% (G:28.26% B:1.27%) Conf: ą 0.011 (-0.237...-0.215)
Duration: 6 hours 47 minutes

¹ 2592 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply

eXtreme Gammon Version: 1.21

White is Player 1

score: 0
pip: 110

Money session
Jacoby Beaver

pip: 173
score: 0

Blue is Player 2

XGID=---A-BBaC--a-BA-bbbcBbBb--:1:1:1:54:0:0:3:0:10
Blue to play 54

1. Rollout¹ 14/10 8/3 eq: -0.114
Player:
Opponent: 41.54% (G:7.07% B:0.26%)
58.46% (G:17.91% B:0.37%) Conf: ą 0.013 (-0.127...-0.101)
Duration: 4 hours 30 minutes
2. Rollout¹ 20/11* eq: -0.184 (-0.070)
Player:
Opponent: 42.53% (G:10.32% B:0.52%)
57.47% (G:32.69% B:1.81%) Conf: ą 0.020 (-0.204...-0.164)
Duration: 5 hours 20 minutes

¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply

eXtreme Gammon Version: 1.21

White is Player 1

score: 0
pip: 110

Money session
Jacoby Beaver

pip: 184
score: 0

Blue is Player 2

XGID=------CaCB-a-BA-bbbcBbBb--:1:1:1:54:0:0:3:0:10
Blue to play 54

1. Rollout¹ 14/5 eq: -0.058
Player:
Opponent: 44.09% (G:7.55% B:0.28%)
55.91% (G:19.69% B:0.36%) Conf: ą 0.011 (-0.069...-0.047)
Duration: 4 hours 30 minutes
2. Rollout¹ 20/11* eq: -0.122 (-0.064)
Player:
Opponent: 44.40% (G:9.84% B:0.47%)
55.60% (G:30.47% B:1.35%) Conf: ą 0.015 (-0.137...-0.107)
Duration: 5 hours 26 minutes

¹ 2300 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply

eXtreme Gammon Version: 1.21

Messages In This Thread

Forwards or backwards?
Timothy Chow -- Tuesday, 14 February 2012, at 11:52 p.m.
- Forwards or backwards?
  John O'Hagan -- Wednesday, 15 February 2012, at 12:13 a.m.
- Forwards or backwards?
  Christian Munk-Christensen -- Wednesday, 15 February 2012, at 9:12 a.m.
  - Forwards or backwards?
    Stick -- Wednesday, 15 February 2012, at 9:19 a.m.
    - Forwards or backwards?
      Christian Munk-Christensen -- Wednesday, 15 February 2012, at 9:30 a.m.
      - Forwards or backwards?
        Stick -- Wednesday, 15 February 2012, at 9:40 a.m.
        
        Forwards or backwards?
        Timothy Chow -- Wednesday, 15 February 2012, at 3:24 p.m.
        
        Forwards or backwards?
        Carlo Melzi -- Wednesday, 15 February 2012, at 3:40 p.m.
        
        Forwards or backwards?
        Timothy Chow -- Thursday, 16 February 2012, at 1:49 a.m.
        
        Forwards or backwards?
        Mr Majestyk -- Wednesday, 15 February 2012, at 3:51 p.m.
        
        Forwards or backwards?
        Stick -- Wednesday, 15 February 2012, at 4:49 p.m.
        
        Forwards or backwards?
        neilkaz -- Wednesday, 15 February 2012, at 5:02 p.m.
- Rollout: Forwards or backwards?
  Timothy Chow -- Thursday, 16 February 2012, at 1:44 a.m.
- Forwards or backwards?
  ah_clem -- Thursday, 16 February 2012, at 4:57 p.m.
- Forwards or backwards? Further analysis
  Timothy Chow -- Wednesday, 22 February 2012, at 12:21 a.m.

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