In the position below I received a cube which, if taken, is for the match. I
have on disk the Two-Sided Bearoff DB for up to 11 chequers on 6 points, which
gives:
Player Opponent
Position 4049 6690
Cubeless equity : +0.5006
Owned cube : +0.7930
Centered cube : +0.7679
Opponent owns cube : +0.4452
It seems to me it is trivially easy to obtain from the Cubeless equity that, if
the game is played out for the match, my opponent will win the match 75.03% of
the time and my MWC is 24.97%. The rollout indeed concurs with these figures
and, for once, 0-ply agrees as well.
As you increase the number of plys from 1-ply through to 7-ply, not only are
all the figures wrong, but, there is a straightforward relatiosnhip of every
ply higher being just as bad or worse than a ply lower. Analysis at 7-ply
produces the worst result. Surely this is not what should be expected, and
shouldn't all plys be bringing the correct figure here?
GNU Backgammon Position ID: tW0AAKjNAQAAAA
Match ID : AQFgAAAAAAAA
+-1--2--3--4--5--6-------7--8--9-10-11-12-+ O: gnubg (Cube: 2)
OO | O O O O O | | | 0 points
O | O O O | | | On roll
O | O | | |
O | | | |
O | | | |
| |BAR| |^ 3 point match
X | | | |
X | | | |
X | | | |
X | X X X X | | |
X | X X X X X X | | | 0 points
+24-23-22-21-20-19------18-17-16-15-14-13-+ X: Neil
Rollout details:
Player gnubg owns 2-cube:
0.744 0.000 0.000 - 0.256 0.000 0.000 CL 62.26% CF 70.82%
[0.000 0.000 0.000 - 0.000 0.000 0.000 CL 0.00% CF 0.00%]
Player Neil owns 4-cube:
0.750 0.000 0.000 - 0.250 0.000 0.000 CL 75.03% CF 75.03%
[0.000 0.000 0.000 - 0.000 0.000 0.000 CL 0.00% CF 0.00%]
Full cubeful rollout with var.redn.
25920 games, Mersenne Twister dice gen. with seed 839486310 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]
Cube analysis
0-ply cubeless MWC 62.55% (Money: +0.501)
0.750 0.000 0.000 - 0.250 0.000 0.000
Cubeful equities:
1. Double, take 75.03%
2. Double, pass 75.08% ( 0.05%)
3. No double 72.29% ( -2.74%)
Proper cube action: Redouble, take
Cube analysis
1-ply cubeless MWC 62.28% (Money: +0.490)
0.745 0.000 0.000 - 0.255 0.000 0.000
Cubeful equities:
1. Double, take 74.48%
2. Double, pass 75.08% ( 0.60%)
3. No double 71.73% ( -2.75%)
Proper cube action: Redouble, take
Cube analysis
2-ply cubeless MWC 62.28% (Money: +0.490)
0.745 0.000 0.000 - 0.255 0.000 0.000
Cubeful equities:
1. Double, take 74.48%
2. Double, pass 75.08% ( 0.59%)
3. No double 70.73% ( -3.76%)
Proper cube action: Redouble, take
Cube analysis
3-ply cubeless MWC 62.28% (Money: +0.490)
0.745 0.000 0.000 - 0.255 0.000 0.000
Cubeful equities:
1. Double, take 74.48%
2. Double, pass 75.08% ( 0.59%)
3. No double 70.64% ( -3.85%)
Proper cube action: Redouble, take
Cube analysis
4-ply cubeless MWC 61.99% (Money: +0.478)
0.739 0.000 0.000 - 0.261 0.000 0.000
Cubeful equities:
1. Double, take 73.92%
2. Double, pass 75.08% ( 1.16%)
3. No double 70.60% ( -3.31%)
Proper cube action: Redouble, take
Cube analysis
5-ply cubeless MWC 61.79% (Money: +0.470)
0.735 0.000 0.000 - 0.265 0.000 0.000
Cubeful equities:
1. Double, take 73.51%
2. Double, pass 75.08% ( 1.57%)
3. No double 70.48% ( -3.03%)
Proper cube action: Redouble, take
Cube analysis
6-ply cubeless MWC 61.77% (Money: +0.469)
0.735 0.000 0.000 - 0.265 0.000 0.000
Cubeful equities:
1. Double, take 73.46%
2. Double, pass 75.08% ( 1.61%)
3. No double 70.44% ( -3.02%)
Proper cube action: Redouble, take
Cube analysis
7-ply cubeless MWC 61.67% (Money: +0.465)
0.733 0.000 0.000 - 0.267 0.000 0.000
Cubeful equities:
1. Double, take 73.27%
2. Double, pass 75.08% ( 1.80%)
3. No double 70.34% ( -2.94%)
Proper cube action: Redouble, take_______________________________________________
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