The position below is almost exactly marginal.
XG's analysis led it to an ultra-marginal pass but it
rolled out to an ultra-marginal take.

My (shamefully Isightless) take was somewhat confident though.
I didn't realise it was 50/50.
The racing methods I used were 10% + 2 and 8/9/12.
10% of 103 + 2 is 12.3 and I'm trailing by less than that.
Also, 12% of 103 = 12.36 and I'm trailing by less than that too.
Furthermore, I think (but am not sure) that such racing methods
underrate the underdog's chances in long races like this one.
Perhaps I needed to add a pip to my count because of my stack on the
ace. Then you get close to the required marginality.

So, a good selling point for a racing method would be that it assesses
this position as marginal.

Paul


XGID=-B---BCB--BA-C-cba-dcb----:0:0:-1:00:8:4:3:0:10
X:eXtremeGammon O:Daniel

Score is X:4 O:8. Unlimited Game, Jacoby Beaver
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O O O | | O O O |
| O O | | O O O |
| | | O |
| | | |
| | | |
| |BAR| |
| | | |
| | | X |
| O X | | X X |
| O X X | | X X X |
| O X X X | | X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 103 O: 114 X-O: 4-8
Cube: 1
X on roll, cube action

Analyzed in Rollout
No double
Player Winning Chances: 78.43% (G:0.03% B:0.00%)
Opponent Winning Chances: 21.57% (G:0.00% B:0.00%)
Double/Take
Player Winning Chances: 78.43% (G:0.03% B:0.00%)
Opponent Winning Chances: 21.57% (G:0.00% B:0.00%)

Cubeless Equities: No Double=+0.569, Double=+1.138

Cubeful Equities:
No double: +0.876 (-0.121)
Double/Take: +0.997
Double/Pass: +1.000 (+0.003)

Best Cube action: Double / Take

Rollout:
1296 Games rolled with Variance Reduction.
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.003 (+0.873..+0.878)
Confidence Double: ± 0.004 (+0.993..+1.000)

Double Decision confidence: 100.0%
Take Decision confidence: 96.1%

Duration: 3 hours 32 minutes

eXtreme Gammon Version: 2.10

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

"peps...@gmail.com" <pepstein5@gmail.com> writes:

XG's analysis led it to an ultra-marginal pass but it
rolled out to an ultra-marginal take.

My Isight count recommends to pass, and not very marginal. You have a
lot of additional crossovers compared to X, and each is penalized with
an additional pip, resulting in 2 percent less winning chances each.

If you move two checkers from your point 13 to 12 and, for compensation
with respect to the pip count, one from your point 7 to 8 and one from
your point 10 to 11, then the Isight count advises to take because of
the 4 percentage point difference in winning chances. However, GNU
Backgammon estimates this new position and your original one as having
only an 0.4 percentage point difference.

So in this position my method clearly overestimates the influence of
additional crossovers.

So, a good selling point for a racing method would be that it assesses
this position as marginal.

A good selling point for a racing method would be that it looses a
minimum amount of equity for a huge number and broad range of positions.
(-:

Best regards

Axel

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)