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Rollout: GNU 2-ply has major issues here!

Posted By: Timothy Chow
Date: Sunday, 22 August 2010, at 1:04 a.m.

In Response To: Post-holding-game cube action (Timothy Chow)

This may be old news to bot experts, but GNU 2-ply has a really tough time with these decisions. In the first position, the rollout indicates a 0.121 pass, but GNU 2-ply thinks it's a 0.213 take! In the second position, the rollout indicates that doubling is O.K., but GNU 2-ply thinks that doubling is a 0.132 error.

I would expect that this kind of position is not all that rare. That means that GNU 2-ply's ER estimate will be noticeably off if such a cube decision arises. Not a problem for me since I don't use ER for anything more than a diagnostic tool, but what do people who make ER bets do with things like this? Has anyone here ever deliberately made the incorrect decision in a position like this for the sake of winning an ER bet?

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gnubg	136
tchow	54
Position ID: vzsDABBs2xAUBg Match ID: AQEAADAAMAAA

Cube decision
Rollout cubeless equity		+0.545
Cubeful equities:
1.	Double, pass	+1.000
2.	Double, take	+1.121	+0.121
3.	No double	+0.916	-0.084
Proper cube action:		Redouble, pass
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Player gnubg owns 2-cube 0.769 0.096 0.002 - 0.231 0.092 0.000 +0.545 +0.916 Standard error 0.001 0.001 0.000 - 0.001 0.001 0.000 0.002 0.005 Player tchow owns 4-cube 0.781 0.122 0.004 - 0.219 0.084 0.000 +1.205 +1.121 Standard error 0.001 0.002 0.000 - 0.001 0.001 0.000 0.006 0.007
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 893591200 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]

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gnubg	136
tchow	53
Position ID: 350BAAi2bQgKAw Match ID: AQEAADAAMAAA

Cube decision
Rollout cubeless equity		+0.422
Cubeful equities:
1.	Double, take	+0.821
2.	Double, pass	+1.000	+0.179
3.	No double	+0.805	-0.016
Proper cube action:		Redouble, take
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Player gnubg owns 2-cube 0.760 0.000 0.000 - 0.240 0.098 0.000 +0.422 +0.805 Standard error 0.001 0.000 0.000 - 0.001 0.001 0.000 0.002 0.005 Player tchow owns 4-cube 0.771 0.000 0.000 - 0.229 0.095 0.001 +0.894 +0.821 Standard error 0.001 0.000 0.000 - 0.001 0.001 0.000 0.005 0.007
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 894380256 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]

Messages In This Thread

• Post-holding-game cube action
  Timothy Chow -- Saturday, 21 August 2010, at 4:14 a.m.
  • Rollout: GNU 2-ply has major issues here!
    Timothy Chow -- Sunday, 22 August 2010, at 1:04 a.m.