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Rollout and some analysis

Posted By: Timothy Chow
Date: Sunday, 11 April 2010, at 12:26 a.m.

In Response To: Blitzing with several checkers back (Timothy Chow)

Daniel's analysis seems to be right on, though I'm still not sure I completely understand what's going on in these positions.

In the first position, I played 24/21 13/7, thinking that I needed more ammunition up front. But it seems that I misjudged how vulnerable this play left me. If you move one of Blue's rear checkers from the 24-point to the midpoint, then 24/21 13/7 becomes a closer contender (not rolled out). Or if you put two of White's checkers on the bar then again 24/21 13/7 is a decent option (see rollout below; probably should be extended, but whatever). But in the given position, getting hit is very expensive for Blue and he needs to think about hedging his bets with Plan B.

In the second position, I thought that the double hit was too committal. It didn't seem likely to buy enough time to really get my checkers around, and the ace-point checkers would not be able to form part of a prime any more. On the other hand, hitting once would at least gain a tempo, which I thought would be useful.

The rollout likes hitting either 0 or 2 times but not just once. In retrospect I can see that since White is stripped, it makes sense to force White to move forwards. Can't say that I really see the virtues of the double hit though.

---

gnubg	148
tchow	153
Position ID: 4NvBEUDWzOAANA Match ID: cIkZAEAAKAAA

#		Ply	Move	Equity
•	1	R	24/15	+0.022
			0.486 0.201 0.005 - 0.514 0.141 0.009 +0.028 +0.022 0.002 0.002 0.000 - 0.002 0.002 0.001 0.004 0.012
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 849261384 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	24/21 13/7	-0.025 ( -0.047)
			0.471 0.202 0.006 - 0.529 0.146 0.010 -0.006 -0.025 0.002 0.002 0.000 - 0.002 0.002 0.001 0.004 0.012
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 849261384 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	157
tchow	153
Position ID: 4NvBAWDWzOAANA Match ID: cIkZAEAAKAAA

#		Ply	Move	Equity
•	1	R	24/21 13/7	+0.424
			0.570 0.280 0.007 - 0.430 0.118 0.008 +0.303 +0.424 0.001 0.002 0.000 - 0.001 0.001 0.000 0.004 0.010
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 848799683 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	23/20 13/7	+0.404 ( -0.020)
			0.565 0.277 0.007 - 0.435 0.117 0.008 +0.290 +0.404 0.001 0.002 0.000 - 0.001 0.001 0.000 0.004 0.010
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 848799683 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	24/15	+0.402 ( -0.022)
			0.565 0.257 0.007 - 0.435 0.119 0.008 +0.267 +0.402 0.002 0.002 0.000 - 0.002 0.002 0.001 0.004 0.012
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 848799683 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	149
tchow	158
Position ID: ZjtgMChsG7AEDg Match ID: cIkEAAAAAAAA

#		Ply	Move	Equity
•	1	R	16/13 14/13	+0.121
			0.522 0.190 0.010 - 0.478 0.149 0.005 +0.088 +0.121 0.001 0.001 0.000 - 0.001 0.001 0.000 0.003 0.008
			Full cubeful rollout with var.redn.
			2592 games, Mersenne Twister dice gen. with seed 848777748 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	3/2*/1*(2)	+0.114 ( -0.007)
			0.513 0.232 0.006 - 0.487 0.175 0.007 +0.081 +0.114 0.001 0.001 0.000 - 0.001 0.001 0.000 0.003 0.008
			Full cubeful rollout with var.redn.
			2592 games, Mersenne Twister dice gen. with seed 848777748 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	16/14 3/2*(2)	+0.087 ( -0.034)
			0.516 0.195 0.011 - 0.484 0.170 0.007 +0.060 +0.087 0.001 0.001 0.000 - 0.001 0.001 0.000 0.003 0.008
			Full cubeful rollout with var.redn.
			2592 games, Mersenne Twister dice gen. with seed 848777748 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	16/15 14/13 3/2*(2)	+0.074 ( -0.047)
			0.510 0.194 0.010 - 0.490 0.168 0.007 +0.048 +0.074 0.001 0.001 0.000 - 0.001 0.001 0.000 0.003 0.008
			Full cubeful rollout with var.redn.
			2592 games, Mersenne Twister dice gen. with seed 848777748 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

• Blitzing with several checkers back
  Timothy Chow -- Friday, 9 April 2010, at 11:15 p.m.
  • Blitzing with several checkers back
    Daniel Murphy -- Saturday, 10 April 2010, at 12:40 a.m.
  • Rollout and some analysis
    Timothy Chow -- Sunday, 11 April 2010, at 12:26 a.m.
    • Rollout and some analysis
      Chase -- Sunday, 11 April 2010, at 12:43 a.m.