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Hit or play safe - RO's

Posted By: Daniel Murphy
Date: Thursday, 27 May 2010, at 6:34 p.m.

In Response To: Hit or play safe (Daniel Murphy)

White	155
Blue	79
Position ID: 7LYAiDHu7DECAA Match ID: cAkFAAAAAAAA

For money it's hard to get a definite answer from Gnubg, but at DMP the play is clear: 12/9. Why? Among the features of the position I would note (1) 12/9 doesn't give White immediate 1-5, 4-5 and 4-4 to hit one of two blots from the bar, plus some possible indirects next roll if White enters without hitting, (2) White's timing is not the best. Left alone he may crash. 12/9 may help with that, because a few of Blue's numbers won't play completely (5-3 5-4 5-5), and (3) after 12/9 Blue may get several whacks at clearing the point without blotting, or perhaps pointing on an unmade 21 point.

For money, these rollouts, rolled out as many trials as I have time for, have 9/7*/6 ahead by a bit when cube is centered and when White has cube. But 2592 and 1905 trials are not enough, and they include imperfect bot afterplay. See the comment below. Also note with respect to the "cubeless" numbers with a centered cube that after 9/7*/6 Blue actually wins more games cubeful than 58% but fewer gammons than 32%, because Blue is cashing when White fans -- so that is 45% of all games that Blue is winning immediately with the cube. There's a rollout for that cube decision below. After 12/9 I doubt if Gnubg 2-ply doubles after most of White's rolls, but I didn't roll any of those sequences out.

MG. Centered Cube. Cube Decision?

After 1,250 trials ND was favored by about 0.020, but still TCTC.

MG. Centered Cube. Blue to play 2-1.

Alert: doubtful move ( -0.014)

#		Ply	Move	Equity
	1	R	9/7*/6	+0.6843
			0.5838 0.3216 0.0400 - 0.4162 0.0375 0.0012 +0.4904 +0.6843 0.0009 0.0009 0.0005 - 0.0009 0.0007 0.0001 0.0023 0.0070
			Full cubeful rollout with var.redn.
			2592 games, Mersenne Twister dice gen. with seed 853267224 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
•	2	R	12/9	+0.6702 ( -0.0141)
			0.6233 0.2531 0.0226 - 0.3767 0.0293 0.0009 +0.4920 +0.6702 0.0010 0.0011 0.0004 - 0.0010 0.0008 0.0001 0.0025 0.0074
			Full cubeful rollout with var.redn.
			2592 games, Mersenne Twister dice gen. with seed 853267224 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

The "alert" is because Gnubg 2-ply plays 12/9 with a centered cube, more likely than not a small error.

MG. Centered cube. Blue on roll. Cube action after 9/7*/6 ... fan.

White	162
Blue	76
Position ID: 7LYAwFju7CMCAA Match ID: cAkAAAAAAAAA

Cube decision
Rollout cubeless equity		+0.6588
Cubeful equities:
1.	Double, pass	+1.0000
2.	Double, take	+1.0543	+0.0543
3.	No double	+0.9204	-0.0796
Proper cube action:		Double, pass
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.6237 0.3720 0.0520 - 0.3763 0.0125 0.0001 +0.6588 +0.9204 Standard error 0.0012 0.0012 0.0007 - 0.0012 0.0010 0.0002 0.0031 0.0078 Player White owns 2-cube 0.6411 0.3832 0.0573 - 0.3589 0.0101 0.0001 +1.4249 +1.0543 Standard error 0.0026 0.0024 0.0015 - 0.0026 0.0009 0.0002 0.0130 0.0184
Full cubeful rollout with var.redn.
648 games, Mersenne Twister dice gen. with seed 853047879 and quasi-random dice
Play: world class 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

MG. Opponent has cube. Blue to play 2-1.

#		Ply	Move	Equity
•	1	R	9/7*/6	+0.3137
			0.5924 0.3312 0.0436 - 0.4076 0.0352 0.0012 +0.5231 +0.3137 0.0017 0.0016 0.0009 - 0.0017 0.0010 0.0001 0.0046 0.0068
			Full cubeful rollout with var.redn.
			1905 games, Mersenne Twister dice gen. with seed 852978195 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	12/9	+0.3126 ( -0.0010)
			0.6234 0.2554 0.0221 - 0.3766 0.0295 0.0008 +0.4939 +0.3126 0.0013 0.0015 0.0006 - 0.0013 0.0008 0.0001 0.0032 0.0051
			Full cubeful rollout with var.redn.
			1905 games, Mersenne Twister dice gen. with seed 852978195 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

Unfortunately the rollout above is marred by at least two other bot errors. After

• Double ... take
• 21: 9/7*/6 ... 45: bar/21/16*
• fan ...

Gnubg 2ply redoubles and takes. Taking is an error. Correcting that error increases the equity for 9/7*/6. But after

• Double ... take
• 21: 9/7*/6 ... 51: bar/24 21/16*
• fan ...

Gnubg 2ply doesn't redouble. Not redoubling may be an error. If so, correcting that error decreases the value of 9/7*/6.

Adjusting roughly for these sequences, 9/7*/6 still seems the slight favorite, but both more trials and better bot afterplay would be good to have (XG, anyone?).

DMP. Blue to play 2-1.

#		Ply	Move	Equity
•	1	R	12/9	+0.2010
			0.6005 0.4129 0.1319 - 0.3995 0.0369 0.0023 +0.2010 +0.2010 0.0044 0.0232 0.0168 - 0.0044 0.0072 0.0009 0.0088 0.0088
			Full cubeful rollout with var.redn.
			180 games, Mersenne Twister dice gen. with seed 852978195 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	9/7*/6	+0.1403 ( -0.0607)
			0.5702 0.3947 0.2056 - 0.4298 0.0304 0.0006 +0.1403 +0.1403 0.0054 0.0131 0.0213 - 0.0054 0.0061 0.0005 0.0107 0.0107
			Full cubeful rollout with var.redn.
			180 games, Mersenne Twister dice gen. with seed 852978195 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

---

Totally off-topic: how to pronounce "Xavier" in Catalan, English, French, Galician, Portuguese, and Valencian:

http://www.forvo.com/word/xavier/

"Nam alii oc, alii si, alii vero dicunt oil."

Messages In This Thread

• Hit or play safe
  Daniel Murphy -- Saturday, 22 May 2010, at 10:58 p.m.
  • Hit or play safe
    nori -- Sunday, 23 May 2010, at 5:13 p.m.
  • Hit or play safe
    Timothy Chow -- Sunday, 23 May 2010, at 10:29 p.m.
  • Hit or play safe
    Chuck Bower -- Monday, 24 May 2010, at 1:41 a.m.
  • Terms for "money"
    Nack Ballard -- Monday, 24 May 2010, at 2:54 a.m.
    • Terms for "money"
      Leonardo Jerkovic -- Monday, 24 May 2010, at 3:06 a.m.
      • DP (Double-match Point) or FP (Final Point)?
        Nack Ballard -- Monday, 24 May 2010, at 3:31 a.m.
        • DP (Double-match Point) or FP (Final Point)?
          bob koca -- Monday, 24 May 2010, at 3:34 a.m.
          • DP (Double-match Point) or FP (Final Point)?
            Nack Ballard -- Monday, 24 May 2010, at 4:20 a.m.
      • Terms for "money"
        Daniel Murphy -- Monday, 24 May 2010, at 3:44 a.m.
        • Terms for "money"
          Nack Ballard -- Monday, 24 May 2010, at 4:02 a.m.
        • Terms for "money"
          Ray Kershaw -- Monday, 24 May 2010, at 9:00 a.m.
    • Terms for "money"
      bob koca -- Monday, 24 May 2010, at 3:32 a.m.
      • Terms for "money"
        Nack Ballard -- Monday, 24 May 2010, at 4:00 a.m.
    • Terms for "money"
      Timothy Chow -- Tuesday, 25 May 2010, at 2:29 p.m.
      • MG acronym
        Nack Ballard -- Tuesday, 25 May 2010, at 5:55 p.m.
        • MG acronym
          Daniel Murphy -- Tuesday, 25 May 2010, at 5:58 p.m.
          • MG acronym
            Nack Ballard -- Wednesday, 26 May 2010, at 7:42 p.m.
        • MG acronym
          Tom Keith -- Tuesday, 25 May 2010, at 7:12 p.m.
        • MG acronym
          Bob Koca -- Tuesday, 25 May 2010, at 7:14 p.m.
        • MG acronym
          Stick -- Tuesday, 25 May 2010, at 11:34 p.m.
          • MG acronym
            Nack Ballard -- Wednesday, 26 May 2010, at 7:35 p.m.
  • Hit or play safe - RO's
    Daniel Murphy -- Thursday, 27 May 2010, at 6:34 p.m.
    • Hit or play safe - RO's
      Timothy Chow -- Friday, 28 May 2010, at 1:59 a.m.