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Rollout: Hit or play safe?

Posted By: Timothy Chow
Date: Sunday, 7 March 2010, at 8:11 p.m.

In Response To: Hit or play safe? (Timothy Chow)

Hitting wins more games (and gammons) and loses more gammons. Here the tradeoff is worth it, partly because Blue's advanced anchor is better placed for running off the gammon than for generating later shots. Give Blue a deuce-point anchor instead, and GNU 4-ply slightly prefers to play safe (see below).

gnubg	92
tchow	137
Position ID: s9sGEAJ2OeAQGA Match ID: UYkFACAAMAAA

#		Ply	Move	Equity
	1	4	17/13	-0.621
			0.225 0.024 0.000 - 0.775 0.166 0.004
	2	4	13/9*	-0.628 ( -0.007)
			0.296 0.065 0.001 - 0.704 0.361 0.025

Rollout of original position:

gnubg	87
tchow	133
Position ID: 29kGEAJ2OeAQBg Match ID: UYkFACAAMAAA

#		Ply	Move	Equity
•	1	R	13/9*	-0.440
			0.352 0.081 0.002 - 0.648 0.367 0.013 -0.593 -0.440 0.001 0.001 0.000 - 0.001 0.002 0.001 0.004 0.006
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 850572759 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	17/13	-0.486 ( -0.045)
			0.270 0.030 0.001 - 0.730 0.160 0.002 -0.593 -0.486 0.001 0.001 0.000 - 0.001 0.002 0.000 0.003 0.004
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 850572759 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

• Hit or play safe?
  Timothy Chow -- Saturday, 6 March 2010, at 8:47 p.m.
  • Hit or play safe?
    Stick -- Saturday, 6 March 2010, at 9:17 p.m.
  • Hit or play safe?
    Chase -- Saturday, 6 March 2010, at 9:27 p.m.
  • Hit or play safe?
    Chuck Bower -- Saturday, 6 March 2010, at 9:30 p.m.
  • Hit or play safe?
    neilkaz -- Sunday, 7 March 2010, at 5:44 a.m.
  • Hit or play safe?
    svilo -- Sunday, 7 March 2010, at 6:53 a.m.
  • Rollout: Hit or play safe?
    Timothy Chow -- Sunday, 7 March 2010, at 8:11 p.m.
    • Rollout: Hit or play safe?
      Stick -- Sunday, 7 March 2010, at 8:39 p.m.