From Newsgroup: rec.games.backgammon

I've been dinged a lot by XG for cashing when too good.
Here, I decided to play on but I didn't give the matter enough thought.
If I counted correctly, I have a 1/6 chance of being forced to blot in
my inner board with the anti-jokers being 61/62/64.
Putting it another way, when I roll a 6, I'm a favourite to blot my inner board.
But the probability of XG hitting me in the next sequence must be significantly more than the 5% given by those anti-jokers. There are quite
a few other rolls which don't blot in the inner board but fail to close out. These rolls give XG indirect shots.
I think that if I had thought all this through, I would have cashed.
But it turns out that playing on is very slightly correct which surprises
me given the above analysis.
I suppose 12% gammons isn't so few and the gammon value might be
elevated.

Paul



XGID=aABBCBC------A---c-dbAcb--:0:0:1:00:8:6:0:11:10

X:Daniel O:XG Roller+
Score is X:8 O:6 11 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X O O |
| O | | O O O O |
| O | | O O |
| | | O |
| | | |
| |BAR| |
| | O | |
| | | |
| | | X X |
| | | X X X X X |
| | | X X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 85 O: 96 X-O: 8-6/11
Cube: 1
X on roll, cube action

Analyzed in 4-ply
Player Winning Chances: 92.82% (G:12.01% B:0.07%)
Opponent Winning Chances: 7.18% (G:1.15% B:0.04%)

Cubeless Equities: No Double=+0.985, Double=+2.043

Cubeful Equities:
No double: +1.013
Double/Take: +1.950 (+0.937)
Double/Pass: +1.000 (-0.013)

Best Cube action: Too good to double / Pass
Percentage of wrong take needed to make the double decision right: 1.4%

eXtreme Gammon Version: 2.10, MET: Kazaross XG2
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From Newsgroup: rec.games.backgammon

On 1/15/2024 5:19 PM, peps...@gmail.com wrote:

But it turns out that playing on is very slightly correct which surprises
me given the above analysis.

The money-game rollout below says to cash, so it has something to do
with the match score and the MET.

XGID=aABBCBC------A---c-dbAcb--:0:0:1:00:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X O O |
| O | | O O O O |
| O | | O O |
| | | O |
| | | |
| |BAR| |
| | O | |
| | | |
| | | X X |
| | | X X X X X |
| | | X X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 85 O: 96 X-O: 0-0
Cube: 1
X on roll, cube action

Analyzed in Rollout
No double
Player Winning Chances: 92.41% (G:12.76% B:0.08%)
Opponent Winning Chances: 7.59% (G:0.79% B:0.02%)
Double/Take
Player Winning Chances: 92.99% (G:12.59% B:0.08%)
Opponent Winning Chances: 7.01% (G:1.21% B:0.05%)

Cubeful Equities:
No double: +0.995 (-0.005)
Double/Take: +1.900 (+0.900)
Double/Pass: +1.000

Best Cube action: Double / Pass

Rollout:
5184 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: -# 0.002 (+0.994..+0.997)
Confidence Double: -# 0.004 (+1.896..+1.903)

eXtreme Gammon Version: 2.19.211.pre-release

---
Tim Chow


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From Newsgroup: rec.games.backgammon

On Tuesday, January 16, 2024 at 1:16:10rC>PM UTC, Timothy Chow wrote:

On 1/15/2024 5:19 PM, peps...@gmail.com wrote:

But it turns out that playing on is very slightly correct which surprises me given the above analysis.

The money-game rollout below says to cash, so it has something to do
with the match score and the MET.

XGID=aABBCBC------A---c-dbAcb--:0:0:1:00:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X O O |
| O | | O O O O |
| O | | O O |
| | | O |
| | | |
| |BAR| |
| | O | |
| | | |
| | | X X |
| | | X X X X X |
| | | X X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 85 O: 96 X-O: 0-0
Cube: 1
X on roll, cube action
Analyzed in Rollout
No double
Player Winning Chances: 92.41% (G:12.76% B:0.08%)
Opponent Winning Chances: 7.59% (G:0.79% B:0.02%)
Double/Take
Player Winning Chances: 92.99% (G:12.59% B:0.08%)
Opponent Winning Chances: 7.01% (G:1.21% B:0.05%)

Cubeful Equities:
No double: +0.995 (-0.005)
Double/Take: +1.900 (+0.900)
Double/Pass: +1.000

Best Cube action: Double / Pass

Rollout:
5184 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: -# 0.002 (+0.994..+0.997)
Confidence Double: -# 0.004 (+1.896..+1.903)

eXtreme Gammon Version: 2.19.211.pre-release

Thanks.
But I haven't been doing rollouts.
So isn't it possible that you're reporting an analysis/rollout difference rather than a match/money difference?
Paul
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From Newsgroup: rec.games.backgammon

On 1/16/2024 11:33 AM, peps...@gmail.com wrote:

But I haven't been doing rollouts.
So isn't it possible that you're reporting an analysis/rollout difference rather than a match/money difference?

I did a match score rollout as well and it confirmed the
4-ply analysis. Maybe I'll post it later, but I have to
run now.

---
Tim Chow

--- Synchronet 3.21b-Linux NewsLink 1.2

From Newsgroup: rec.games.backgammon

On 1/17/2024 9:07 AM, I wrote:

On 1/16/2024 11:33 AM, peps...@gmail.com wrote:

But I haven't been doing rollouts.
So isn't it possible that you're reporting an analysis/rollout difference
rather than a match/money difference?

I did a match score rollout as well and it confirmed the
4-ply analysis. Maybe I'll post it later, but I have to
run now.

XGID=aABBCBC------A---c-dbAcb--:0:0:1:00:8:6:0:11:10

Score is X:8 O:6 11 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X O O |
| O | | O O O O |
| O | | O O |
| | | O |
| | | |
| |BAR| |
| | O | |
| | | |
| | | X X |
| | | X X X X X |
| | | X X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 85 O: 96 X-O: 8-6/11
Cube: 1
X on roll, cube action

Analyzed in Rollout
No double
Player Winning Chances: 92.50% (G:12.75% B:0.07%)
Opponent Winning Chances: 7.50% (G:0.76% B:0.02%)
Double/Take
Player Winning Chances: 93.19% (G:12.27% B:0.16%)
Opponent Winning Chances: 6.81% (G:1.22% B:0.05%)

Cubeful Equities:
No double: +1.013
Double/Take: +1.969 (+0.957)
Double/Pass: +1.000 (-0.013)

Best Cube action: Too good to double / Pass
Percentage of wrong take needed to make the double decision right: 1.3%

Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: -# 0.004 (+1.009..+1.016)
Confidence Double: -# 0.006 (+1.964..+1.975)

eXtreme Gammon Version: 2.19.211.pre-release, MET: Kazaross XG2

---
Tim Chow

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