Re: [Bug-gnubg] Luck analysis question

[Joern Thyssen]

On Wed, Jun 11, 2003 at 11:28:22AM -0300, Albert Silver wrote
> Perhaps one interesting way to examine this would be to run GNU 0.12,
> the version that played sgainst Snowie 3.2, and have it analyze the luck
> factor and see what the results are. 
> 
> The reason I was a bit concerned is this: the luck is NOT independent of
> the evaluation of the moves and positions as I see it. It is entirely
> dependent in fact. Suppose in a given position, I say the equity is
> 0.400, move A is the best giving that 0.400 equity, and move B is a
> blunder leading to only 0.250. Mind you, this is because I do not
> realize that mave B is in fact stronger and leads to 0.450. You
> correctly play move B, I play a move that does nothing still thinking it
> is only 0.250, and you play a move that improves the position by a mere
> 0.050. When I analyze this new resulting position, I now see the truth
> of it and see that the current equity is 0.500, however having misjudged
> it previously will declare you're a lucky guy whose move led to a 0.250
> gain. 

I hope Nis has answered most of your questions. 

BTW, you can actually easily calculate the luck for a given position
using the new temperature map. 

 GNU Backgammon  Position ID: 4HPhQSDgc/ABMA
                 Match ID   : cAkbAAAAAAAA
 +13-14-15-16-17-18------19-20-21-22-23-24-+     O: gnubg
 | X        O  O    |   | O              X |     0 points
 | X           O    |   | O              X |
 | X           O    |   | O                |
 | X                |   | O                |
 | X                |   | O                |
v|                  |BAR|                  |     (Cube: 1)
 |                  |   | X                |
 | O                |   | X                |
 | O           X    |   | X                |
 | O           X    |   | X                |     Rolled 66
 | O           X  O |   | X              O |     0 points
 +12-11-10--9--8--7-------6--5--4--3--2--1-+     X: jth
Pip counts: O 157, X 167

Using the temperature map I see that my 1-ply equity is +0.016, and the
0-ply equity for 66 is +0.580 (assuming I move 24/18(2) 13/7(2)*). 

Thus, my luck from rolling 66 is 0.564.

Jørn