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Rollout. I'm not yet convinced this is an easy problem

Posted By: Timothy Chow
Date: Sunday, 7 March 2010, at 7:57 p.m.

In Response To: I didn't think I could lose so much equity while bearing in (Timothy Chow)

The rollout confirms that breaking the 7 point is superior, but why is this? For comparison, see the variant position below, where breaking the 8-point comes out slightly ahead, according to GNU 4-ply. What makes the two positions so different? The explanations I've seen so far do not seem to distinguish between these two positions.

gnubg	98
tchow	78
Position ID: tm0LEAJXs80AAA Match ID: QYkUABAAAAAA

#		Ply	Move	Equity
	1	4	8/7 8/3	+0.471
			0.768 0.016 0.000 - 0.232 0.009 0.000
	2	4	7/6 7/2	+0.466 ( -0.005)
			0.760 0.028 0.000 - 0.240 0.012 0.000

Here's the rollout of the original position.

gnubg	86
tchow	80
Position ID: 27YJEAJXs40BAA Match ID: QYkUABAAAAAA

#		Ply	Move	Equity
•	1	R	7/6 7/2	+0.230
			0.663 0.015 0.000 - 0.337 0.031 0.001 +0.310 +0.230 0.001 0.001 0.000 - 0.001 0.001 0.000 0.002 0.002
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 849611280 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	8/7 8/3	+0.147 ( -0.083)
			0.631 0.011 0.000 - 0.369 0.031 0.001 +0.241 +0.147 0.001 0.001 0.000 - 0.001 0.001 0.000 0.002 0.002
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 849611280 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

• I didn't think I could lose so much equity while bearing in
  Timothy Chow -- Saturday, 6 March 2010, at 8:39 p.m.
  • I didn't think I could lose so much equity while bearing in
    Stick -- Saturday, 6 March 2010, at 9:13 p.m.
  • I didn't think I could lose so much equity while bearing in
    Chuck Bower -- Saturday, 6 March 2010, at 9:27 p.m.
    • I didn't think I could lose so much equity while bearing in
      garyo -- Sunday, 7 March 2010, at 6:25 p.m.
  • I didn't think I could lose so much equity while bearing in
    Chase -- Saturday, 6 March 2010, at 9:28 p.m.
  • Contact Variations, NonContact Variations and Crossovers
    Paul Weaver -- Saturday, 6 March 2010, at 11:47 p.m.
  • Rollout. I'm not yet convinced this is an easy problem
    Timothy Chow -- Sunday, 7 March 2010, at 7:57 p.m.
    • Rollout. I'm not yet convinced this is an easy problem
      Stick -- Sunday, 7 March 2010, at 8:31 p.m.
    • Rollout. I'm not yet convinced this is an easy problem
      Chase -- Sunday, 7 March 2010, at 9:03 p.m.