Re: [Bug-gnubg] Wrong cube errors categories in analysis statistics panel

[Jim Segrave]

Warning - from someone whose theory is less than awe-inspiring"


Imagine MSC as a line, increasing in value left to right:


You lose------------------------------------------------You win gammon
                DP               CP        TG
         1      |   2        3   |   4    5 | 6

The numbers represent regions of MWC.

So for each region, the limits and associated errors:

1 = MWC < DP, error:
        double:    wrong double around DP
        no double: no error
        take:      no error
        drop:      wrong drop round DP

2 = DP < MWC < .5 * ( DP + CP)
        double:    no error
        no double: missed double around DP
        take:      no error
        drop:      wrong drop round DP
        
3 = .5 * ( DP + CP) < MWC < CP
        double:    no error
        no double: missed double around CP
        take:      no error
        drop:      wrong drop round CP

4 = CP < MWC < .5 * (CP + TG)
        double:    no error
        no double: missed double around CP
        take:      wrong take around CP
        drop:      no error

5 = .5 * (CP + TG) < MWC < TG
        double:    no error
        no double: missed double around TG
        take:      wrong take around TG
        drop:      no error

6 = TG < MWC 
        double:    wrong double around TG
        no double: no error
        take:      wrong take around TG
        drop:      no error

Re the other questions

> Does someone know why getMatchPoints() does this and whether this is
> intended?

I can't reproduce this.

>From today's CVS, gdb output reformatted for ease of readability:

Breakpoint 2, TheoryUpdated (pw=0x899c740, ptw=0x899b900) at gtktheory.c:331
1: aaarPointsMatch = {{{0.42115128, 0.328579843}, 
                      {0.589850724, 0.589850724}, 
                      {0.759432137, 0.767605424}, 
                      {0.947443664, 0.767605424}}, 

                     {{0.240567863, 0.232394576}, 
                      {0.410149246, 0.410149246}, 
                      {0.57884872,  0.671420157}, 
                      {0.808395922, 0.671420157}}}
(gdb) 

And for player 0 in the Market Window, I see the values exactly as
reported above, converted to percentages. There's no swapping visible.

For those who want to test this, this is from:

    GNU Backgammon  Position ID: sLnJAEzYvg0ICA
                    Match ID   : cInxAAAACAAA


> To categorize cubes gnubg compares the arithmetic means of DP and
> CP, and CP and TG with the winning probabilities.  Could someone
> please explain me why (and confirm that) this is correct?

See above, I think it is correct.

> I'm wondering about the following: The winning probability
> (aarOutput[ 0 ][ OUTPUT_WIN ]) doesn't include any added value for
> gammon or bg chances (aarOutput[ 0 ][ OUTPUT_WINGAMMON ] and
> aarOutput[ 0 ][ OUTPUT_WINBACKGAMMON ]). Those match points (DP, CP,
> TG) have an entity of cubeful equity, don't they? And I think
> equities are calculated as the sum of winning chances, gammon
> chances and bg chances, thus include gammon and bg value. If all
> this was correct so far, then I suppose these 2 values can't be
> compared.

This seems a good point - I think picking the point needs to be done
in terms of MWC, it's not enough to do equity, since in some match
points, gammons are irre;evant.

-- 
Jim Segrave           address@hidden