And playing a single match I stumbled
on yet another case
(though much less spactacular than
the previous one).
GNU Backgammon Position
ID: rG3IAEzY5g1DAA
Match ID : UQngAAAAEAAA
+24-23-22-21-20-19------18-17-16-15-14-13-+
O: gnubg
|
O O O O | O | O X O
X | 0 points
|
O O O | | O
X |
|
| |
|
|
| |
|
|
| |
|
|
|BAR|
|v 7 point match
|
| |
|
|
| | X
|
|
| | X
|
| O
X X X | | X X
O | On roll
| O
X X X | | X X
O | 2 points
+-1--2--3--4--5--6-------7--8--9-10-11-12-+
X: MaX (Cube: 2)
Massimiliano Maini/NCE/AMADEUS wrote
on 26/02/2009 10:23:08:
> Hi all,
>
> on bgonline this cube decision has been posted and the evals returned
by gnubg
> are crazy on even ply:
>
> GNU Backgammon Position ID: XgAAILftgAARAA
>
Match ID : AQEAAAAAAAAA
> +-1--2--3--4--5--6-------7--8--9-10-11-12-+
O: gnubg (Cube: 2)
> | O
O O O O | |
| 0 points
> | O
O O O O | |
| On roll
> | O
O | |
|
> |
| |
|
> |
| |
|
> |
|BAR|
|^
> X |
| |
|
> XX | X
| |
|
> XX | X
| |
|
> XX | X
| |
|
> XX | O X X O
| X |
O | 0 points
> +24-23-22-21-20-19------18-17-16-15-14-13-+
X: MaX
>
> The original one was in ma match, with score 9aw-9aw: I changed it
to money
> to simplify since it doesn't make
any difference.
>
> Cube analysis
> 0-ply cubeless equity +0.190
> 0.610 0.000 0.000 - 0.390
0.027 0.003
> Cubeful equities:
> 1. No double
+0.398
> 2. Double, pass
+1.000 ( +0.602)
> 3. Double, take
+0.116 ( -0.282)
> Proper cube action: No redouble,
take (31.9%)
>
> Cube analysis
> 1-ply cubeless equity +0.464
> 0.747 0.000 0.000 - 0.253
0.027 0.003
> Cubeful equities:
> 1. Double, take
+0.756
> 2. Double, pass
+1.000 ( +0.244)
> 3. No double
+0.695 ( -0.062)
> Proper cube action: Redouble,
take
>
> Cube analysis
> 2-ply cubeless equity +0.245
> 0.637 0.000 0.000 - 0.363
0.026 0.003
> Cubeful equities:
> 1. No double
+0.462
> 2. Double, pass
+1.000 ( +0.538)
> 3. Double, take
+0.244 ( -0.218)
> Proper cube action: No redouble,
take (28.9%)
>
> Cube analysis
> 3-ply cubeless equity +0.503
> 0.765 0.000 0.000 - 0.235
0.025 0.003
> Cubeful equities:
> 1. Double, take
+0.844
> 2. Double, pass
+1.000 ( +0.156)
> 3. No double
+0.796 ( -0.048)
> Proper cube action: Redouble,
take
>
> Cube analysis
> 4-ply cubeless equity +0.288
> 0.658 0.000 0.000 - 0.342
0.025 0.003
> Cubeful equities:
> 1. No double
+0.532
> 2. Double, pass
+1.000 ( +0.468)
> 3. Double, take
+0.342 ( -0.189)
> Proper cube action: No redouble,
take (28.8%)
>
> Position ID: XgAAILftgAARAA
> Match ID: AQEAAAAAAAAA
> Evaluator: Crashed
> Win
W(g) W(bg) L(g) L(bg)
Equity Cubeful
> static: 0.610 0.000
0.000 0.027 0.003 +0.190 +0.398
> 1 ply: 0.747 0.000
0.000 0.027 0.003 +0.464 +0.695
> 2 ply: 0.637 0.000
0.000 0.026 0.003 +0.245 +0.462
> 3 ply: 0.765 0.000
0.000 0.025 0.003 +0.503 +0.796
> 4 ply: 0.658 0.000
0.000 0.025 0.003 +0.288 +0.532
>
> Cubeless winning chances swing a lot between even and odd plies, while
> gammon and backgammon percentages
are very stable.
> Notice that even W% increase 0/2/4ply,
but so do odd ones 1ply/3ply.
>
> Can we still blame this on odd-even effect ?
>
> MaX.
>
> P.S.
> The thread on bgonline is this
one:
>
> http://www.bgonline.org/forums/webbbs_config.pl?noframes;read=35362
>
> Neil said that it wasn't worth to do a 2ply cube rollout since the
results
> would be garbage, due to the fact
2ply eval screws this position big time.
> However, the (stopped) rollout
2ply chequer/2ply cube gave the same result
> as the (stopped) rollout 2ply
chequer/3ply cube and both were similar to 3ply
> eval. Rollout/eval figures are
in this post:
>
> http://www.bgonline.org/forums/webbbs_config.pl?noframes;read=35416
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