Sometimes gnubg doesn't report beavers correctly. For example, consider
the following extreme position:
GNU Backgammon Position ID: Pp8PAAAAAPh8Pg
Match ID : cAkAAAAAAAAA
+24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
| X O X O X O | | | 0 points
| X O X O X O | | |
| X O X O X O | | |
| X O X O X O | | |
| X O X O X O | | |
| |BAR| |v (Cube: 1)
| | | |
| | | |
| | | |
| | | | On roll
| | | | 0 points
+-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: Chris
Pip counts: O 60, X 330
X is playing an extreme 15-checker backgame. X owns the cube and is on
roll.
0-ply, 1-ply, 2-ply, and 4-ply analysis (no reduced evaluations) all
state that X is a cubeless underdog. Therefore, 0-ply, 1-ply, 2-ply,
and 4-ply evaluations should definitely be no-redouble/beaver. However
gnubg says it's no-redouble/take at 0-ply, 2-ply, and 4-ply. At 1-ply
it correctly says that it's a no-redouble/beaver.
I'm using gnubg for Windows version 0.14-devel 1.1227 030727 (build Jul
27 2003).
Here is gnubg's display for 0-ply through 4-ply (for both the hint and
evaluations windows):
0-ply:
Cube analysis
0-ply cubeless equity -2.120
7.9% 0.0% 0.0% - 92.1% 87.0% 40.8%
Cubeful equities:
1. No double -2.093
2. Double, pass +1.000 ( +3.093)
3. Double, take -4.297 ( -2.204)
Proper cube action: No redouble, take (41.6%)
1-ply:
Cube analysis
1-ply cubeless equity -0.012
67.8% 0.2% 0.0% - 32.2% 26.6% 10.4%
Cubeful equities:
1. No double +0.218
2. Double, pass +1.000 ( +0.782)
3. Double, take -0.243 ( -0.462)
Proper cube action: No redouble, beaver (37.1%)
2-ply:
Cube analysis
2-ply cubeless equity -2.091
7.5% 0.0% 0.0% - 92.5% 86.5% 37.5%
Cubeful equities:
1. No double -2.066
2. Double, pass +1.000 ( +3.066)
3. Double, take -4.237 ( -2.172)
Proper cube action: No redouble, take (41.5%)
3-ply [note: the bug doesn't apply here; the interpretation of
no-redouble/take is correct since .139 > 0]:
Cube analysis
3-ply cubeless equity +0.159
73.7% 0.1% 0.0% - 26.3% 22.0% 9.6%
Cubeful equities:
1. No double +0.414
2. Double, pass +1.000 ( +0.586)
3. Double, take +0.139 ( -0.275)
Proper cube action: No redouble, take (32.0%)
4-ply:
Cube analysis
4-ply cubeless equity -2.027
6.9% 0.0% 0.0% - 93.1% 85.1% 31.3%
Cubeful equities:
1. No double -2.004
2. Double, pass +1.000 ( +3.004)
3. Double, take -4.107 ( -2.104)
Proper cube action: No redouble, take (41.2%)
Chris
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