Position of the Day 03-05-25 - Non Standard backgame cube

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Position of the Day 03-05-25 - Non Standard backgame cube - Rollout

Posted By: Philippe Michel
Date: Monday, 24 March 2025, at 9:30 p.m.

In Response To: Position of the Day 03-05-25 - Non Standard backgame cube - Rollout (Stick)

XG 3-ply doesn't seem to play the containment from the White side very well.
A GNUbg rollout with a large move filter has the double/take equity lower by about 0.1 in the original position and by a little less than this in variant 2. It sees variant 1 as a big no double.
I suppose a strong player could do even better, although probably far from enough to make the original position a non double.
Unlimited game, Jacoby rule
GNUbg 194

You 55
Position ID: sG1A0A37w0cAAA Match ID: cAkAAAAAAAAA

You doubles

Cube decision

Rollout cubeless equity +0.666

Cubeful equities:

1. Double, take +0.802

2. Double, pass +1.000 +0.198

3. No double +0.587 -0.214

Proper cube action: Double, take

Rollout details

Win W g W bg Lose L g L bg Cubeless Cubeful

Centered 1-cube 0.588 0.506 0.013 - 0.412 0.029 0.001 +0.666 +0.587

Standard deviation 0.001 0.001 0.000 - 0.001 0.001 0.000 0.003 0.006

GNUbg owns 2-cube 0.574 0.494 0.012 - 0.426 0.029 0.001 +1.248 +0.802

Standard deviation 0.001 0.002 0.000 - 0.001 0.001 0.000 0.008 0.014

Full cubeful rollout with variance reduction

1296 games, Mersenne Twister dice gen. with seed 8 and quasi-random dice

Play: supremo 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 16 more moves within equity 0.32

skip pruning for 1-ply moves

Cube: 2-ply cubeful prune [world class]