[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

BGonline.org Forums

Rollout and analysis: Find the right maxim

Posted By: Timothy Chow
Date: Monday, 28 May 2012, at 6:31 p.m.

In Response To: Find the right maxim (Timothy Chow)

Truncated rollouts only. Someone with a better computer than I have may wish to perform full rollouts, especially of the variant below.

The relevant maxim, I think, is Magriel's criteria, which point to a safe play (i.e., 13/10, which is clearly better than 5/2). We don't have enough of a race lead to mandate racing, and White's position is too strong for us to hit. Sometimes, stepping out to the 18pt (which is what I tried) is safer than staying back, despite the greater number of shots, but not here; Blue's board is fairly strong, so White's loose hits on her 4pt after 13/10 aren't as strong as her hits on her bar point after bar/18.

An interesting variant is obtained if we move the spare on the 13pt to the 6pt and shift the 3pt to the 2pt. This eliminates 13/10 as an option. The hit is more attractive now because White's 3's are duplicated (giving her only 15 return shots instead of 21) and Blue has an extra checker in the zone. Running with bar/18 is also more attractive than before because Blue is further ahead in the race, and the alternative 6/3 leaves Blue with a relatively weak board. Though the safe play is still probably best, the decision is much closer.





White is Player 1

score: 0
pip: 134
Money session
Jacoby Beaver
pip: 133
score: 0

Blue is Player 2
XGID=---BbCBaB-B-bC---b-bb-bb-A:1:1:1:43:0:0:3:0:10
Blue to play 43

1.Rollout1Bar/21 13/10eq: +0.260
Player:
Opponent:		 54.14% (G:11.03% B:0.59%)
45.86% (G:13.89% B:0.28%)		Conf: ± 0.008 (+0.252...+0.268)
Duration: 4 minutes 00 second
2.Rollout1Bar/18eq: +0.149 (-0.111)
Player:
Opponent:		 51.10% (G:8.56% B:0.41%)
48.90% (G:14.78% B:0.27%)		Conf: ± 0.006 (+0.143...+0.155)
Duration: 3 minutes 58 seconds
3.Rollout1Bar/21 10/7* eq: +0.112 (-0.148)
Player:
Opponent:		 50.51% (G:12.45% B:0.66%)
49.49% (G:21.54% B:1.12%)		Conf: ± 0.007 (+0.105...+0.119)
Duration: 2 minutes 55 seconds
4.Rollout1Bar/21 5/2eq: +0.107 (-0.152)
Player:
Opponent:		 49.84% (G:11.53% B:0.62%)
50.16% (G:18.68% B:0.50%)		Conf: ± 0.008 (+0.099...+0.115)
Duration: 3 minutes 14 seconds
1 Truncated at 7 moves using 3 ply.
648 Games rolled with Variance Reduction.
Dice Seed: 2
First 2 moves and cube decisions: 3 ply
Remaining moves: 2 ply, cube decisions: 3 ply

eXtreme Gammon Version: 1.21

Variant:





White is Player 1

score: 0
pip: 134
Money session
Jacoby Beaver
pip: 124
score: 0

Blue is Player 2
XGID=--B-bCCaB-B-bB---b-bb-bb-A:1:1:1:43:0:0:3:0:10
Blue to play 43

1.Rollout1Bar/21 6/3eq: +0.185
Player:
Opponent:		 51.60% (G:13.19% B:0.72%)
48.40% (G:16.38% B:0.49%)		Conf: ± 0.008 (+0.177...+0.193)
Duration: 3 minutes 06 seconds
2.Rollout1Bar/18eq: +0.175 (-0.011)
Player:
Opponent:		 51.48% (G:9.39% B:0.43%)
48.52% (G:13.98% B:0.38%)		Conf: ± 0.006 (+0.169...+0.181)
Duration: 3 minutes 38 seconds
3.Rollout1Bar/21 10/7* eq: +0.173 (-0.012)
Player:
Opponent:		 51.60% (G:13.38% B:0.63%)
48.40% (G:18.93% B:1.04%)		Conf: ± 0.008 (+0.165...+0.181)
Duration: 2 minutes 45 seconds
1 Truncated at 7 moves using 3 ply.
648 Games rolled with Variance Reduction.
Dice Seed: 2
First 2 moves and cube decisions: 3 ply
Remaining moves: 2 ply, cube decisions: 3 ply

eXtreme Gammon Version: 1.21

Messages In This Thread

 

Post Response
Your Name:
Your E-Mail Address:
Subject:
Message:

If necessary, enter your password below:

Password:
 

 

[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

BGonline.org Forums is maintained by Stick with WebBBS 5.12.