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Rollouts: Late blitz cube quiz

Posted By: Timothy Chow
Date: Monday, 4 October 2010, at 10:56 p.m.

In Response To: Late blitz cube quiz (Timothy Chow)

No takers? Could be that this quiz was too hard. Certainly I find these decisions difficult, and in some cases so does GNU 2-ply, which often overestimates the defender's chances (below, I include GNU 2-ply eval as well as a rollout for each position).

I think these kinds of positions are important; they come up quite a lot, often after a sudden turnaround, when there is a temptation to react emotionally rather than rationally. There's also often quite a bit of equity at stake. But despite their importance, there does not seem to be much literature on late blitz cubes. In Robertie's 501 Essential Backgammon Problems, his short chapter on late blitzes has only one cube decision, where the blitzer is much too good.

I'm not going to offer any further verbal commentary on the positions below at this point, because I don't understand them well enough. I hope to play around with more variants, after which I may have something intelligent to say.

---

Problem 1

gnubg	143
tchow	151
Position ID: mHOaQUAzG/ABMA Match ID: MAEAAKAAAAAA

• gnubg doubles

Cube decision
Rollout cubeless equity		+0.599
Cubeful equities:
1.	Double, take	+0.870
2.	Double, pass	+1.000	+0.130
3.	No double	+0.691	-0.179
Proper cube action:		Double, take
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.636 0.400 0.019 - 0.364 0.088 0.004 +0.599 +0.691 Standard error 0.001 0.001 0.001 - 0.001 0.001 0.000 0.003 0.008 Player tchow owns 2-cube 0.636 0.395 0.015 - 0.364 0.085 0.004 +1.185 +0.870 Standard error 0.002 0.002 0.001 - 0.002 0.001 0.000 0.009 0.014
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 844690511 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]

Cube decision
2-ply cubeless equity		+0.612
	0.639 0.411 0.020 - 0.361 0.093 0.004
Cubeful equities:
1.	Double, take	+0.978
2.	Double, pass	+1.000	+0.022
3.	No double	+0.700	-0.278
Proper cube action:		Double, take

---

Problem 2

gnubg	127
tchow	126
Position ID: uD2DA0DY5nKCAA Match ID: MAEAACAAKAAA

• gnubg doubles

Cube decision
Rollout cubeless equity		+0.511
Cubeful equities:
1.	Double, take	+0.883
2.	Double, pass	+1.000	+0.117
3.	No double	+0.798	-0.086
Proper cube action:		Double, take
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.729 0.101 0.002 - 0.271 0.049 0.001 +0.511 +0.798 Standard error 0.001 0.001 0.000 - 0.001 0.001 0.000 0.003 0.006 Player tchow owns 2-cube 0.741 0.103 0.003 - 0.259 0.051 0.002 +1.068 +0.883 Standard error 0.002 0.002 0.000 - 0.002 0.001 0.000 0.008 0.010
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 848520688 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]

Cube decision
2-ply cubeless equity		+0.488
	0.716 0.113 0.002 - 0.284 0.059 0.001
Cubeful equities:
1.	Double, take	+0.784
2.	Double, pass	+1.000	+0.216
3.	No double	+0.737	-0.048
Proper cube action:		Double, take

---

Problem 3

gnubg	127
tchow	139
Position ID: 5mwDMEG2c4iADA Match ID: AQEAAGAAGAAA

• gnubg doubles

Cube decision
Rollout cubeless equity		+0.609
Cubeful equities:
1.	Double, pass	+1.000
2.	Double, take	+1.063	+0.063
3.	No double	+0.811	-0.189
Proper cube action:		Redouble, pass
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Player gnubg owns 2-cube 0.655 0.392 0.012 - 0.345 0.100 0.005 +0.609 +0.811 Standard error 0.001 0.002 0.001 - 0.001 0.001 0.000 0.004 0.006 Player tchow owns 4-cube 0.672 0.411 0.009 - 0.328 0.096 0.005 +1.325 +1.063 Standard error 0.002 0.003 0.001 - 0.002 0.001 0.001 0.010 0.014
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 848616888 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]

Cube decision
2-ply cubeless equity		+0.528
	0.630 0.364 0.017 - 0.370 0.108 0.004
Cubeful equities:
1.	Double, take	+0.808
2.	Double, pass	+1.000	+0.192
3.	No double	+0.719	-0.089
Proper cube action:		Redouble, take

---

Problem 4

gnubg	151
tchow	169
Position ID: 4DMbMEFsnhEELA Match ID: MAEAAFAACAAA

• gnubg doubles

Cube decision
Rollout cubeless equity		+0.546
Cubeful equities:
1.	Double, take	+0.903
2.	Double, pass	+1.000	+0.097
3.	No double	+0.735	-0.168
Proper cube action:		Double, take
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.631 0.353 0.022 - 0.369 0.088 0.004 +0.546 +0.735 Standard error 0.001 0.002 0.001 - 0.001 0.001 0.000 0.004 0.010 Player tchow owns 2-cube 0.648 0.383 0.015 - 0.352 0.087 0.005 +1.203 +0.903 Standard error 0.002 0.003 0.001 - 0.002 0.002 0.001 0.013 0.018
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 853383854 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]

Cube decision
2-ply cubeless equity		+0.480
	0.611 0.344 0.023 - 0.389 0.102 0.006
Cubeful equities:
1.	Double, take	+0.696
2.	Double, pass	+1.000	+0.304
3.	No double	+0.626	-0.070
Proper cube action:		Double, take

---

Problem 5

gnubg	89
tchow	128
Position ID: 2G4jA0A725gACA Match ID: AQEAACAAAAAA

• gnubg doubles

Cube decision
Rollout cubeless equity		+0.592
Cubeful equities:
1.	Double, take	+0.916
2.	Double, pass	+1.000	+0.084
3.	No double	+0.737	-0.179
Proper cube action:		Redouble, take
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Player gnubg owns 2-cube 0.657 0.319 0.001 - 0.343 0.041 0.001 +0.592 +0.737 Standard error 0.001 0.002 0.000 - 0.001 0.001 0.000 0.002 0.005 Player tchow owns 4-cube 0.661 0.324 0.001 - 0.339 0.040 0.001 +1.211 +0.916 Standard error 0.001 0.002 0.000 - 0.001 0.001 0.000 0.005 0.007
Full cubeful rollout with var.redn.
2592 games, Mersenne Twister dice gen. with seed 849007741 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]

Cube decision
2-ply cubeless equity		+0.574
	0.633 0.349 0.003 - 0.367 0.043 0.001
Cubeful equities:
1.	Double, take	+0.902
2.	Double, pass	+1.000	+0.098
3.	No double	+0.752	-0.150
Proper cube action:		Redouble, take

---

Problem 6

gnubg	116
tchow	136
Position ID: cLcxA0DbbMABCg Match ID: AQEAAAAAAAAA

• gnubg doubles

Cube decision
Rollout cubeless equity		+0.618
Cubeful equities:
1.	Double, pass	+1.000
2.	Double, take	+1.064	+0.064
3.	No double	+0.852	-0.148
Proper cube action:		Redouble, pass
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Player gnubg owns 2-cube 0.664 0.359 0.002 - 0.336 0.068 0.003 +0.618 +0.852 Standard error 0.001 0.002 0.000 - 0.001 0.001 0.000 0.003 0.005 Player tchow owns 4-cube 0.680 0.372 0.002 - 0.320 0.064 0.003 +1.335 +1.064 Standard error 0.001 0.002 0.000 - 0.001 0.001 0.000 0.007 0.009
Full cubeful rollout with var.redn.
2592 games, Mersenne Twister dice gen. with seed 848681527 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]

Cube decision
2-ply cubeless equity		+0.553
	0.641 0.350 0.003 - 0.359 0.078 0.003
Cubeful equities:
1.	Double, take	+0.863
2.	Double, pass	+1.000	+0.137
3.	No double	+0.799	-0.065
Proper cube action:		Redouble, take

---

Problem 7

gnubg	105
tchow	129
Position ID: 2M4NA0DbbDADEA Match ID: MAEAAEAAMAAA

• gnubg doubles

Cube decision
Rollout cubeless equity		+0.576
Cubeful equities:
1.	Double, take	+0.915
2.	Double, pass	+1.000	+0.085
3.	No double	+0.748	-0.167
Proper cube action:		Double, take
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.663 0.307 0.002 - 0.337 0.056 0.002 +0.576 +0.748 Standard error 0.001 0.002 0.000 - 0.001 0.001 0.000 0.004 0.008 Player tchow owns 2-cube 0.669 0.310 0.001 - 0.331 0.055 0.002 +1.184 +0.915 Standard error 0.002 0.003 0.000 - 0.002 0.001 0.000 0.009 0.014
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 892677369 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]

Cube decision
2-ply cubeless equity		+0.553
	0.646 0.321 0.002 - 0.354 0.060 0.002
Cubeful equities:
1.	Double, take	+0.865
2.	Double, pass	+1.000	+0.135
3.	No double	+0.704	-0.161
Proper cube action:		Double, take

---

Problem 8

gnubg	126
tchow	156
Position ID: NhtwMFBsN8hiAA Match ID: AgEAAAAACAAA

• gnubg doubles

Cube decision
Rollout cubeless equity		+0.723
Cubeful equities:
1.	Double, pass	+1.000
2.	Double, take	+1.253	+0.253
3.	No double	+0.971	-0.029
Proper cube action:		Redouble, pass
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Player gnubg owns 4-cube 0.701 0.384 0.016 - 0.299 0.077 0.002 +0.723 +0.971 Standard error 0.001 0.002 0.001 - 0.001 0.001 0.000 0.004 0.010 Player tchow owns 8-cube 0.707 0.403 0.014 - 0.293 0.077 0.004 +1.500 +1.253 Standard error 0.002 0.002 0.001 - 0.002 0.001 0.000 0.010 0.015
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 896452672 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]

Cube decision
2-ply cubeless equity		+0.690
	0.695 0.354 0.021 - 0.305 0.073 0.001
Cubeful equities:
1.	Double, pass	+1.000
2.	Double, take	+1.173	+0.173
3.	No double	+0.931	-0.069
Proper cube action:		Redouble, pass

Messages In This Thread

• Late blitz cube quiz
  Timothy Chow -- Sunday, 3 October 2010, at 2:31 a.m.
  • Late blitz cube quiz
    Stick -- Sunday, 3 October 2010, at 2:39 a.m.
    • Late blitz cube quiz
      Timothy Chow -- Sunday, 3 October 2010, at 3:00 a.m.
      • Late blitz cube quiz
        Stick -- Sunday, 3 October 2010, at 3:03 a.m.
  • Rollouts: Late blitz cube quiz
    Timothy Chow -- Monday, 4 October 2010, at 10:56 p.m.
    • Brutal
      David -- Tuesday, 5 October 2010, at 2:23 p.m.
  • Late blitz cube quiz
    Timothy Chow -- Monday, 31 October 2011, at 3:22 p.m.
    • Late blitz cube quiz
      Stick -- Tuesday, 1 November 2011, at 2:24 a.m.
      • Late blitz cube quiz
        Timothy Chow -- Tuesday, 1 November 2011, at 2:42 p.m.