Re: Michael Petch V's monty - First Match

Michael Petch wrote:
> Racoon said:
>> I would (and still would) have passed. The 2-ply evaluation is
>> obviously bad. One doesn't win one-third of the time with two checkers
>> on the roof about to be closed out and and only 10 checkers off. 3-ply
>> evaluation is better here -- 17.3% GWC for you, instead of 33%.
>>
>> Monty might have considered doubling the roll before.
>>
> 
> The previous rollout I did was 3ply checker, 3 ply cube (Which is what
is
> posted in the analysis). Below is a copy of the rollout results at 3 ply
> checker/2ply cube (Instead of 3). Its the second time in a few years
where I
> had encountered a "Too good to cube / TAKE" position.
> 

How can GNU evaluate this as too good for Monty?  The probability of 
Monty winning a gammon is 0.

> You be the judge, but I'm still dropping this puppy!
> 
> The score (after 2 games) is: mpetch 1, Monty 4 (match to 15 points)
> Match Information:
> 
> Date: April 13, 2008
> Move number 67:  Monty on roll, cube decision? GNU Backgammon  Position
ID:
> BwAAmG1bCkEAAA
>                  Match ID   : UQngARAAIAAA
>  +13-14-15-16-17-18------19-20-21-22-23-24-+     O: mpetch
>  |    X             | O | X              O | OO  1 point
>  |                  | O |                O | OO
>  |                  |   |                O | OO
>  |                  |   |                  | OO
>  |                  |   |                  | OO
> v|                  |BAR|                  |     15 point match
>  |                  |   |                  |
>  |                  |   |                  |
>  |                  |   |                  |
>  |                  |   | X  X  X  X  X    |     On roll
>  |       X  X     X |   | X  X  X  X  X    |     4 points
>  +12-11-10--9--8--7-------6--5--4--3--2--1-+     X: Monty (Cube: 2)
> Pip counts: O 53, X 99
> 
> * Monty doubles
> 
> Alert: wrong double ( -0.025)! [very bad]
> Cube analysis
> Rollout cubeless equity  +0.587 (Money:  +0.587)
> 
> Cubeful equities:
> 1. No double            +1.015
> 2. Double, pass         +1.000  ( -0.015)
> 3. Double, take         +0.990  ( -0.025)
> Proper cube action: Too good to redouble, take
> Rollout details:
> Player Monty owns 2-cube:
>   0.795 0.000 0.000 - 0.205 0.003 0.000 CL  +0.587 CF  +1.015
>  [0.001 0.000 0.000 - 0.001 0.000 0.000 CL   0.003 CF   0.005]
> Player mpetch owns 4-cube:
>   0.800 0.000 0.000 - 0.200 0.004 0.001 CL  +1.178 CF  +0.990
>  [0.001 0.000 0.000 - 0.001 0.000 0.000 CL   0.006 CF   0.007]
> Full cubeful rollout with var.redn.
> 1296 games, Mersenne Twister dice gen. with seed 824585691 and
quasi-random
> dice
> Play: grandmaster 3-ply cubeful prune [grandmaster]
> keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
> Skip pruning for 1-ply moves.
> keep the first 0 2-ply moves and up to 2 more moves within equity 0.04
> Cube: 2-ply cubeful prune [world class]
>