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

BGonline.org Forums

Rollout: Bearing in with no contact

Posted By: Timothy Chow
Date: Tuesday, 17 August 2010, at 10:28 p.m.

In Response To: Bearing in with no contact (Timothy Chow)

Congratulations to Mochy, who got this one right.

In general it's bad to have a big stack on the 6 point with fewer checkers on the 5 point and/or 4 point than on lower points. Thus 6/5 is clear for the ace. Then at first glance, 10/6 seems obvious for the 4. But why does it seem obvious? It shouldn't, because it stacks up on the 6 point when the 5 point and 4 point don't have many checkers on them.

But you may say, if I don't bear in the checker on the 10 point then I might not even get to bear off a checker next turn if I roll 31 or 21 or 11! However, those rolls are bad rolls in any case, and after 7/3, 21 and 11 can be productively played to smooth your distribution by moving a checker from the 6 point to the 4 point. On the flip side of the coin, playing 10/6 means that if you roll two large numbers, they will tend to play worse than after 7/3.

The other objection to 7/3 is that it buries a checker deep. This is certainly a concern, and if the roll had been 51 instead of 41 then 6/5 7/2 would be a big mistake. (But note that with 51, the best play is not 10/5 7/6 but is instead 10/5 6/5!) However, the 3 point is not quite deep enough to outweigh the advantages of 7/3.

gnubg60


'2X2X3X4X3X ' ' ' ' ' '

2O3O2O1O1O4O1O ' '1O ' '

tchow64

Position ID: tnsHAIDd6kUAAA Match ID: cAkGACAAIAAA

# Ply Move Equity
• 1 R 7/3 6/5 -0.561
0.3110.0000.000-0.6890.0000.000 -0.377 -0.561
0.0000.0000.000-0.0000.0000.000 0.000 0.001
Full cubeful rollout with var.redn.
5184 games, Mersenne Twister dice gen. with seed 893891620 and quasi-random dice
Play: supremo 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]
2 R 10/5 -0.572 ( -0.012)
0.3120.0000.000-0.6880.0000.000 -0.375 -0.572
0.0000.0000.000-0.0000.0000.000 0.000 0.001
Full cubeful rollout with var.redn.
5184 games, Mersenne Twister dice gen. with seed 893891620 and quasi-random dice
Play: supremo 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

Here's another example, from the roll immediately preceding the above one. As you can see, I misplayed this one too. It's much better to shore up the 4 point than to stack up on the 6 point.

gnubg67


'2X2X3X4X3X1X ' ' ' ' '

2O3O2O1O '3O1O '1O1O1O '

tchow73

Position ID: tnsXAAC75VIBAA Match ID: cIkZACAAIAAA

# Ply Move Equity
• 1 R 11/5 7/4 -0.326
0.3860.0000.000-0.6140.0000.000 -0.227 -0.326
0.0000.0000.000-0.0000.0000.000 0.000 0.001
Full cubeful rollout with var.redn.
5184 games, Mersenne Twister dice gen. with seed 893749910 and quasi-random dice
Play: supremo 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]
2 R 11/5 9/6 -0.373 ( -0.047)
0.3720.0000.000-0.6280.0000.000 -0.256 -0.373
0.0000.0000.000-0.0000.0000.000 0.000 0.001
Full cubeful rollout with var.redn.
5184 games, Mersenne Twister dice gen. with seed 893749910 and quasi-random dice
Play: supremo 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

One final example from our chouette, so that MCG doesn't complain again about the lack of content of my posts. This time I got it right OTB. I was captain, and my team members wanted to bear one, but I overruled them because it seemed likely that bearing one now would likely lead to missing twice with 4's (or even 1's) later on.

Box57


2X2X2X3X3X3X ' ' ' ' ' '

1O5O2O1O '5O '1O ' ' ' '

Team59

Position ID: 2+4OAAB9yycAAA Match ID: QQkWAAAAAAAA

# Ply Move Equity
• 1 R 8/4 6/1 -0.464
0.3770.0000.000-0.6230.0000.000 -0.245 -0.464
0.0000.0000.000-0.0000.0000.000 0.000 0.001
Full cubeful rollout with var.redn.
5184 games, Mersenne Twister dice gen. with seed 897555538 and quasi-random dice
Play: world class 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]
2 R 8/3 4/off -0.504 ( -0.040)
0.3630.0000.000-0.6370.0000.000 -0.274 -0.504
0.0000.0000.000-0.0000.0000.000 0.000 0.001
Full cubeful rollout with var.redn.
5184 games, Mersenne Twister dice gen. with seed 897555538 and quasi-random dice
Play: world class 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

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.