RE: [Bug-gnubg] Hint on cube decisions

[Ian Shaw]

I think that gnubg is still showing the hint for the original doubling
decision. Gnubg's analysis of beavers is not fully implemented, if I
recall correctly.

You seem to be using the command line. When I use the GUI and ask for a
hint when user beavers, I get a blank window.

Perhaps one of the coders can comment further.

Regards,
Ian Shaw 

> -----Original Message-----
> From: Kari Uusitalo [mailto:address@hidden 
> Sent: 16 June 2006 16:17
> To: Ian Shaw
> Cc: address@hidden
> Subject: Re: [Bug-gnubg] Hint on cube decisions
> 
> Thanks, that helped!
> 
> Still I wonder the beaver/redouble things. I tried it with 
> two human players and the results were somewhat odd as you 
> can see below. I have but some comments and a quiestion in between.
> 
> BR,
> Kari
> 
> The game output:
> 
> (user) hint
> 
> Cube analysis
> 2-ply cubeless equity  +0.872
>   0.773 0.345 0.043 - 0.227 0.059 0.002
> Cubeful equities:
> 1. Double, pass         +1.000
> 2. Double, take         +1.589  ( +0.589)
> 3. No double            +0.971  ( -0.029)
> Proper cube action: Double, pass
> 
> >>>>>>
> The doubling seems like a very good advice as we are leading 
> so heavily.
> >>>>>>
> 
> (user) double
> user doubles.
>  GNU Backgammon  Position ID: YefBADhsm8gRQA
>                  Match ID   : cBEAAAAAAAAA
>  +13-14-15-16-17-18------19-20-21-22-23-24-+     O: gnubg
>  | X        X  O    |   | O  O           O |     0 points
>  | X           O    |   | O  O             |     Cube offered at 2
>  | X           O    |   | O                |
>  |             O    |   |                  |
>  |                  |   |                  |
> v|                  |BAR|                  |
>  |                  |   |                  |
>  |                  |   |                  |
>  |                  |   |                O |
>  | O                |   | X  X  X  X     O |
>  | O  X        X    | X | X  X  X  X     O |     0 points
>  +12-11-10--9--8--7-------6--5--4--3--2--1-+     X: user
> 
> (gnubg) hint
> Take decision:
> 
> Equity for take: -1.589
> Equity for pass: -1.000
> 
> Your proper cube action: Pass.
> 
> >>>>>>
> This also seems like a good advice as gnubg player is behind 
> so clearly.
> 
> However, he redoubles just for this test.
> >>>>>>
> 
> (gnubg) beaver
> gnubg accepts and immediately redoubles to 4.
>  GNU Backgammon  Position ID: YefBADhsm8gRQA
>                  Match ID   : QRkAAAAAAAAA
>  +13-14-15-16-17-18------19-20-21-22-23-24-+     O: gnubg
>  | X        X  O    |   | O  O           O |     0 points
>  | X           O    |   | O  O             |
>  | X           O    |   | O                |
>  |             O    |   |                  |
>  |                  |   |                  |
> v|                  |BAR|                  |
>  |                  |   |                  |
>  |                  |   |                  |
>  |                  |   |                O |
>  | O                |   | X  X  X  X     O |     Cube offered at 4
>  | O  X        X    | X | X  X  X  X     O |     0 points
>  +12-11-10--9--8--7-------6--5--4--3--2--1-+     X: user
> 
> (user) hint
> Take decision:
> 
> Equity for take: -1.592
> Equity for pass: -1.000
> 
> Your proper cube action: Pass.
> 
> >>>>>>
> How can the correct action be to "Pass" when the user is 
> leading so much?
> >>>>>>
> 
> 2006/6/16, Ian Shaw <address@hidden>:
> >
> >  From: Kari Uusitalo Sent: 16 June 2006 11:38
> >
> > > I am playing around with the GNU BG and tried to find info about 
> > > what excatly different lines mean in hint ouputs ofr cube 
> selection.
> > >
> > > For example, I have the cube in a certain game situation and the 
> > > hint returns:
> > >
> > > >>>>>>>>
> > > Cube analysis
> > > 2-ply cubeless equity  -0.039
> > >   0.479 0.108 0.002 - 0.521 0.105 0.002 Cubeful equities:
> > > 1. No double            +0.124
> > > 2. Double, pass         +1.000  ( +0.876)
> > > 3. Double, take         -0.433  ( -0.556)
> > > Proper cube action: No redouble, beaver (38.8%)
> > > >>>>>>>>
> > >
> > > What exactly the different lines mean. I guess, the last line
> > > is the most important and in this case I should not double.
> > > What does the "beaver"-text in that particular line mean and
> > > what does the percentage figure stand for?
> >
> > When an opponent doubles, some games allow to to Beaver. 
> E.g. If Player
> > A doubles to 2, Player B can Beaver to 4 - keeping the cube 
> on his side.
> >
> > Roughly speaking, you should beaver if your opponent has doubled you
> > when you are the favourite to win, as in the example above. 
> The opponent
> > is expected to win 52.1% of the games, so gnubg recommends that you
> > don't double, but if you do, then the opponent should beaver.
> >
> >
> > The 38.8% figure means that the double would be correct if 38.8% of
> > opponents were to mistakenly pass the double.
> >
> > I hope this helps.
> >
> > -- Ian Shaw
> >
> >
> >
>