[Bug-gnubg] Different evaluations by CONTACT network

[Ian Shaw]

Here's another position where the 0, 1 and 2-ply networks have large
differences of opinion. Static thinks it's a Pass, but 1 and 2-ply have
Take.

    GNU Backgammon  Position ID: 2LZJAFjavQMAGA
                    Match ID   : AQEAAAAAAAAA
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+  O: GnuBg (Cube: 2)
    | X  O  O  O  O  O |   |                  |  0 points
    | X     O  O  O  O |   |                  |  On roll
    |          O  O  O |   |                  |  
    |             O    |   |                  |  
    |                  |   |                  |  
    |                  |BAR|                  |^ 
    |                  |   |                  |  
    |                  |   |                  |  
    |                  |   |                  |  
    |    O     X  X  X |   | X  X             |  
    |    O     X  X  X | X | X  X     X     X |  0 points
    +24-23-22-21-20-19------18-17-16-15-14-13-+  X: ian


Evaluator:      CONTACT

Input           Value                    dE/dI
OFF1            0.000                   -0.044
OFF2            0.000                    0.005
OFF3            1.000                   -0.069
BREAK_CONTACT   0.000                   -0.045
BACK_CHEQUER    0.000                   -0.067
BACK_ANCHOR     0.000                   -0.160
FORWARD_ANCHOR  0.000                   -0.055
PIPLOSS         1.000 (0.000 avg)       -0.255
P1              0.000 (0.000/36)        -0.054
P2              1.000 (36.000/36)       -0.286
BACKESCAPES     0.000 (0.000/36)        -0.149
ACONTAIN        1.000 (36.000/36)       -0.332
CONTAIN         0.000 (0.000/36)        -0.283
MOBILITY        0.000                   -0.164
MOMENT2         0.000                   -0.051
ENTER           0.000 (0.000/12)        -0.112
ENTER2          0.000                   -0.044
TIMING          0.000                   -0.031
BACKBONE        0.000                   -0.024
BACKGAME        0.000                    0.050
BACKGAME1       0.000                   -0.025
FREEPIP         0.000                   -0.468

        Win     W(g)    W(bg)   L(g)    L(bg)   Equity  (cubeful)
static: 0.776   0.234   0.009   0.124   0.017   (+0.652  (+1.000))
 1 ply: 0.704   0.179   0.005   0.136   0.011   (+0.446  (+0.690))
 2 ply: 0.748   0.210   0.007   0.127   0.015   (+0.571  (+0.970))


Redouble, take      : +0.970
Redouble, pass      : +1.000   (+0.030)
No redouble         : +0.835   (-0.135)

Correct cube action: Redouble, take


Regards
Ian Shaw