Discussion:
Step up?
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Tim Chow
2020-06-18 15:46:51 UTC
Permalink
XGID=-b-B-BFaB-B------bbb-bbbA-:1:-1:1:42:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O O | | O O O O X | +---+
| O O | | O O O O | | 2 |
| | | | +---+
| | | |
| | | |
| |BAR| |
| | | 6 |
| | | X |
| | | X |
| X X | | X X X O |
| X X O | | X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 112 O: 126 X-O: 0-0
Cube: 2, O own cube
X to play 42

---
Tim Chow
Tim Chow
2020-06-21 17:07:44 UTC
Permalink
XGID=-b-B-BFaB-B------bbb-bbbA-:1:-1:1:42:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O O | | O O O O X | +---+
| O O | | O O O O | | 2 |
| | | | +---+
| | | |
| | | |
| |BAR| |
| | | 6 |
| | | X |
| | | X |
| X X | | X X X O |
| X X O | | X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 112 O: 126 X-O: 0-0
Cube: 2, O own cube
X to play 42

X is ahead in the pip count and the main alternative to stepping up,
namely making the 4pt, leaves a direct shot anyway. So I decided to
play 24/20 6/4. However, the rollout strongly favors making the 4pt.
I guess I overestimated the danger that my straggler might not be able
to escape.

1. Rollout¹ 8/4 6/4 eq:-0.084
Player: 51.57% (G:17.61% B:1.45%)
Opponent: 48.43% (G:12.34% B:0.44%)
Confidence: ±0.009 (-0.093..-0.075) - [100.0%]

2. Rollout¹ 24/20 6/4 eq:-0.165 (-0.081)
Player: 51.25% (G:15.43% B:1.08%)
Opponent: 48.75% (G:18.27% B:0.50%)
Confidence: ±0.008 (-0.173..-0.157) - [0.0%]

¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.19.207.pre-release

---
Tim Chow
Paul Epstein
2020-06-21 18:52:22 UTC
Permalink
Post by Tim Chow
XGID=-b-B-BFaB-B------bbb-bbbA-:1:-1:1:42:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O O | | O O O O X | +---+
| O O | | O O O O | | 2 |
| | | | +---+
| | | |
| | | |
| |BAR| |
| | | 6 |
| | | X |
| | | X |
| X X | | X X X O |
| X X O | | X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 112 O: 126 X-O: 0-0
Cube: 2, O own cube
X to play 42
X is ahead in the pip count and the main alternative to stepping up,
namely making the 4pt, leaves a direct shot anyway. So I decided to
play 24/20 6/4. However, the rollout strongly favors making the 4pt.
I guess I overestimated the danger that my straggler might not be able
to escape.
I doubt that you really overestimated that. It is a tough escape which is
why all plays leave you in negative equity.
Both the correct play and your play leave a direct shot but yours
leaves about twice as many shots. Note that with the correct play,
your opponent can only hit with an ace.
The rollout opinion is that sacrificing a lot of extra shots for the chance
to escape is not worth it.

Your play doesn't look bad to me.
If you suggested it as a chouette captain, I would have been perfectly
fine with it.

Paul
Tim Chow
2020-06-22 03:45:42 UTC
Permalink
Post by Paul Epstein
Both the correct play and your play leave a direct shot but yours
leaves about twice as many shots. Note that with the correct play,
your opponent can only hit with an ace.
Good point. I think I underestimated how bad it is (after my play) to
get hit with a 2.

---
Tim Chow

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