BGonline.org Forums

Rollout

Posted By: Timothy Chow
Date: Saturday, 12 December 2009, at 9:03 p.m.

In Response To: To hit or not to hit (Timothy Chow)

GNU recommends hitting. This position is a variant of a position that actually came up in a game that I was watching. In the actual game, it was White's 5-point that was open, and I thought the hit was clear. Blue considered the hit but eventually chickened out. Looking at it with GNU afterwards, I asked myself how deeply one could move White's open point and still have hitting be right. Before the computer analysis, I was on the fence with an open 3-point and would not have hit with an open 2-point.

With an open 1-point, hitting is too dangerous, as most people would correctly assume. I have also included a rollout of this case below, for reference.

gnubg	121
tchow	87
Position ID: s22CAVC27TQQAA Match ID: QYkYAAAAAAAA

#		Ply	Move	Equity
•	1	R	8/1*	+1.172
			0.843 0.574 0.011 - 0.157 0.040 0.001 +1.229 +1.172 0.001 0.002 0.001 - 0.001 0.001 0.000 0.003 0.005
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 839830609 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	15/9 6/5	+1.151 ( -0.021)
			0.891 0.416 0.008 - 0.109 0.009 0.000 +1.196 +1.151 0.001 0.002 0.000 - 0.001 0.001 0.000 0.003 0.004
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 839830609 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]
	3	R	15/8	+1.147 ( -0.025)
			0.886 0.425 0.009 - 0.114 0.010 0.000 +1.194 +1.147 0.001 0.002 0.001 - 0.001 0.001 0.000 0.003 0.004
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 839830609 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]

gnubg	123
tchow	87
Position ID: tm2CAVC27TQQAA Match ID: QYkYAAAAAAAA

#		Ply	Move	Equity
•	1	R	15/8	+1.100
			0.892 0.354 0.007 - 0.108 0.001 0.000 +1.145 +1.100 0.001 0.002 0.000 - 0.001 0.000 0.000 0.003 0.004
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 839415928 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	15/9 6/5	+1.100 ( -0.000)
			0.893 0.354 0.007 - 0.107 0.001 0.000 +1.145 +1.100 0.001 0.002 0.000 - 0.001 0.000 0.000 0.003 0.004
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 839415928 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]
	3	R	15/9 8/7	+1.036 ( -0.065)
			0.854 0.390 0.007 - 0.146 0.009 0.000 +1.096 +1.036 0.001 0.002 0.000 - 0.001 0.001 0.000 0.003 0.004
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 839415928 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]
	4	R	8/1*	+1.028 ( -0.073)
			0.802 0.538 0.008 - 0.198 0.045 0.002 +1.102 +1.028 0.001 0.002 0.001 - 0.001 0.001 0.000 0.004 0.006
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 839415928 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

• To hit or not to hit
  Timothy Chow -- Friday, 11 December 2009, at 9:48 p.m.
  • To hit or not to hit
    David -- Friday, 11 December 2009, at 10:16 p.m.
  • To hit or not to hit
    Rich Munitz -- Saturday, 12 December 2009, at 12:06 a.m.
  • To hit or not to hit
    Neil Robins -- Saturday, 12 December 2009, at 3:57 a.m.
    • To hit or not to hit
      neilkaz -- Saturday, 12 December 2009, at 4:37 a.m.
  • To hit or not to hit
    Nack Ballard -- Saturday, 12 December 2009, at 4:48 a.m.
    • To hit or not to hit
      Rich Munitz -- Saturday, 12 December 2009, at 5:35 a.m.
  • Rollout
    Timothy Chow -- Saturday, 12 December 2009, at 9:03 p.m.
    • XG rollouts
      Petter Bengtsson -- Saturday, 12 December 2009, at 10:19 p.m.