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World's incorrect 14-away/6-away pass: Analysis
Posted By: Daniel Murphy In Response To: World's incorrect 14-away/6-away pass: Analysis (Matt Cohn-Geier)
Date: Wednesday, 14 April 2010, at 1:08 a.m.
I wonder if there isn't a not so complex lesson from the rollouts, which is that a position something like this should in one's reference book. For me, at least, it was a surprise to learn that Team World wins nearly 25% of the time from the 4-cube position at this score. If you could guesstimate that, along with a live cube take point of ~15% and dead cube take point of ~22%, then the take decision would have been easier, no?
I can also add more data:
(1) For money, it's "only" a ~0.100 pass.
(2) For money, Gnubg 0-ply checker play gets nearly the same result for Blue as 2-ply. Comparing match score to money game (0-ply):
White Match Money Wins (total) 24.5% 21.0% Wins Gammon on 8-cube 00.3% 00.1% Wins Gammon on 4-cube 00.0% 00.4% Wins Single on 16-cube 00.0% 00.6% Wins Single on 8-cube 05.1% 05.0% Wins Single on 4-cube 19.4% 14.9% Loses Single on 4-cube 66.1% 73.3% Loses Single on 8-cube 05.6% 01.4% Loses Single on 16-cube 00.0% 00.6% Loses Gammon on 4-cube 03.2% 03.7% Loses Gammon on 8-cube 00.3% 00.0% Loses (total) 75.5% 79.0% Recubes to 8 30.4% 22.3% Redouble to 8/take 11.3% 14.6% Redouble to 8/pass 19.1% 07.7% Redouble to 16/take 00.0% 01.2% Redouble to 16/pass 00.0% 01.4% Redouble to 16/pass 00.0% 00.6% So ... ATS White gets in a redouble 30% of the time, instead of 22%, and 37% of those redoubles are taken, instead of 65% (not too surprising, I suppose, since White's market window on an 8 cube is ~25%-~62% ATS, instead of 50%-~78%).
For example suppose we have a redouble after rolling an ace if Denmark does nothing special
Something like this?
The score (after 0 games) is: World 1, Denmark 7 (match to 15 points)
Move number 57: World on roll, cube decision?
World 58
Denmark 75 Position ID: 4902AADvcwMACA Match ID: AgHgARAAOAAA
• World doubles
Cube decision Rollout cubeless equity -0.184 (Money: -0.204) Cubeful equities: 1. Double, take +0.100 2. Double, pass +1.000 +0.900 3. No double +0.037 -0.063 Proper cube action: Redouble, take Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Player World owns 4-cube 0.408 0.007 0.000 - 0.592 0.027 0.000 -0.184 +0.037 Standard error 0.002 0.001 0.000 - 0.002 0.004 0.000 0.004 0.006 Player Denmark owns 8-cube 0.410 0.005 0.000 - 0.590 0.030 0.000 +0.100 +0.100 Standard error 0.003 0.001 0.000 - 0.003 0.013 0.000 0.010 0.010 Full cubeful rollout with var.redn. 145 games, Mersenne Twister dice gen. with seed 854265860 and quasi-random dice Play: 2-ply cubeful prune [world class] keep the first 0 0-ply moves and up to 20 more moves within equity 0.44 Skip pruning for 1-ply moves. Cube: 2-ply cubeful prune [world class]
Above, another lesson for me: that Team World wins ~41% from here. Supposing that ~27% is from an immediate six, I wouldn't have thought White could pick up another ~14% from other sequences.
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