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DQ: Why or why not break the anchor? Rollout of double

Posted By: Timothy Chow
Date: Saturday, 14 February 2015, at 6:49 p.m.

In Response To: DQ: Why or why not break the anchor? Rollout of double (leobueno)

Thanks, Leo. I got around to doing a couple of rollouts myself.

The first position below is the same as yours except that I've changed the score to an unlimited game, to avoid peculiarities associated with the particular score such as the gammon values. Breaking anchor still comes out on top. The interesting thing is that the computer doubles as White after the anchor-breaking play but does not double after the board-breaking play; nevertheless the play that provokes the cube turn comes out ahead.

The second position below is the same as the first position but with Blue owning the cube. Now the two plays are essentially tied. In effect we are "forcing" White to double after either play.

---

		White is Player 2 score: 0 pip: 109 Unlimited Game pip: 100 score: 0 Blue is Player 1
XGID=-ABCBbB-C--a------bccBb-b-:1:-1:1:65:0:0:0:0:10
Blue to play 65

1.	Rollout1	21/16 21/15	eq: -0.599
	Player: Opponent: 37.95% (G:6.89% B:0.26%) 62.05% (G:24.97% B:0.71%) Conf.: ± 0.012 (-0.611...-0.587) - [100.0%] Duration: 13 minutes 53 seconds
2.	Rollout2	8/2 6/1	eq: -0.655 (-0.056)
	Player: Opponent: 35.27% (G:4.06% B:0.06%) 64.73% (G:14.99% B:0.49%) Conf.: ± 0.008 (-0.664...-0.647) - [0.0%] Duration: 6 minutes 14 seconds
1 1296 Games rolled with Variance Reduction. Rolled for both No double and Double Dice Seed: 271828 First 3 moves: 3-ply, cube decisions: XG Roller+ Remaining moves: 3-ply, cube decisions: XG Roller 2 1296 Games rolled with Variance Reduction. Dice Seed: 271828 Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.19.208.pre-release

---

		White is Player 2 score: 0 pip: 109 Unlimited Game pip: 100 score: 0 Blue is Player 1
XGID=-ABCBbB-C--a------bccBb-b-:1:1:1:65:0:0:0:0:10
Blue to play 65

1.	Rollout1	8/2 6/1	eq: -0.290
	Player: Opponent: 34.75% (G:3.75% B:0.06%) 65.25% (G:14.38% B:0.45%) Conf.: ± 0.006 (-0.297...-0.284) - [95.8%] Duration: 5 minutes 15 seconds
2.	Rollout1	21/16 21/15	eq: -0.298 (-0.007)
	Player: Opponent: 37.80% (G:6.93% B:0.27%) 62.20% (G:24.64% B:0.68%) Conf.: ± 0.006 (-0.303...-0.292) - [4.2%] Duration: 5 minutes 14 seconds
1 1296 Games rolled with Variance Reduction. Dice Seed: 271828 Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.19.208.pre-release

Messages In This Thread

• DQ: Why or why not break the anchor?
  leobueno -- Sunday, 8 February 2015, at 6:11 p.m.
  • DQ: Why or why not break the anchor?
    Timothy Chow -- Sunday, 8 February 2015, at 6:50 p.m.
    • DQ: Why or why not break the anchor?
      leobueno -- Sunday, 8 February 2015, at 7:31 p.m.
  • DQ: Why or why not break the anchor? *** Rollout ***
    leobueno -- Monday, 9 February 2015, at 8:04 p.m.
    • DQ: Why or why not break the anchor? *** Rollout ***
      Timothy Chow -- Tuesday, 10 February 2015, at 12:44 a.m.
      • DQ: Why or why not break the anchor? Rollout of double
        leobueno -- Tuesday, 10 February 2015, at 7:41 p.m.
        • DQ: Why or why not break the anchor? Rollout of double
          Timothy Chow -- Saturday, 14 February 2015, at 6:49 p.m.
  • DQ: Why or why not break the anchor?
    Kevin Finch -- Saturday, 14 February 2015, at 3:24 a.m.
    • DQ: Why or why not break the anchor?
      Timothy Chow -- Saturday, 14 February 2015, at 7:10 p.m.