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Rollout

Posted By: Timothy Chow
Date: Wednesday, 11 November 2009, at 1:42 a.m.

In Response To: Blue to play 65 (Timothy Chow)

Over the board, I played 22/11 automatically. I'm annoyed with myself for not even considering 22/16 13/8. This is a case of failing to follow my own advice of making sure to look at blotty plays when I have a stronger board.

It is pretty clear that 22/16 13/8 wins more gammons. Leaving four blots around seems like it has to lose more games, or at least it will result in a larger fraction of losses being gammon losses, but the question is how much. Duplication is important here; 22/11 leaves 5 shots, and 22/16 13/8 leaves 7 shots—only two extra shots. Of course it's also hard to clean up four blots should the need arise. Is the risk worth it? I don't think I would have assessed it correctly over the board even if I had thought about it.

The rollout clearly favors 22/16 13/8.

gnubg	136
tchow	95
Position ID: 2G0TYEDbzUADCA Match ID: UYkaAAAACAAA

#		Ply	Move	Equity
•	1	R	22/16 13/8	+0.778
			0.684 0.396 0.002 - 0.316 0.070 0.006 +0.689 +0.778 0.001 0.003 0.000 - 0.001 0.001 0.000 0.004 0.005
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 870235326 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	22/11	+0.735 ( -0.044)
			0.676 0.308 0.002 - 0.324 0.055 0.002 +0.605 +0.735 0.001 0.003 0.000 - 0.001 0.001 0.000 0.004 0.007
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 870235326 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

• Blue to play 65
  Timothy Chow -- Monday, 9 November 2009, at 1:54 a.m.
  • Blue to play 65
    Andreas -- Monday, 9 November 2009, at 7:34 a.m.
    • Blue to play 65
      Nack Ballard -- Monday, 9 November 2009, at 10:14 p.m.
      • capito :- ) ty *NM*
        Andreas -- Tuesday, 10 November 2009, at 4:25 p.m.
  • Blue to play 65
    Keene -- Monday, 9 November 2009, at 3:15 p.m.
  • Blue to play 65
    Chuck Bower -- Monday, 9 November 2009, at 5:40 p.m.
  • Rollout
    Timothy Chow -- Wednesday, 11 November 2009, at 1:42 a.m.