Lyudmil Tsvetkov wrote:
maybe you will share your code with us?
Sure. This is the functional change over the Stockfish master I checked out this morning:
Code: Select all
--- Stockfish/src/material.cpp 2017-07-18 13:21:30.000000000 +0200
+++ Nightfish/src/material.cpp 2017-07-18 23:05:43.000000000 +0200
@@ -121,6 +121,10 @@
if (pieceCount[Us][QUEEN] == 1 && pieceCount[Them][QUEEN] == 0)
bonus += QueenMinorsImbalance[pieceCount[Them][KNIGHT] + pieceCount[Them][BISHOP]];
+ // Elephantiasis correction for Q vs N
+ if (pieceCount[Them][KNIGHT] > 2)
+ bonus -= 16*112*(pieceCount[Them][KNIGHT] - 2)*pieceCount[Us][QUEEN];
+
return bonus;
}
I had originally missed that Stockfish scales the imbalance correction by a factor 16 (so they are not in... whatever you'd call the evaluation unit in Stockfish). The factor "112" corresponds to 60cp. Note that this is not quite enough to reduce the evaluation in the root position to "balanced". Evaluation still favours the queens by about 100cp.
from what position?
The relevant start position,
[d]nnnnknnn/pppppppp/8/8/8/8/PPPPPPPP/1Q1KQ1Q1 w - -
how many games?
Six or seven at various time controls, but I'll start a longer series to run overnight.
what TC?
40/0:30. I ran a couple at 40/1:00. At longer time controls the Queens hang in there better (or perhaps it's the correction to the score, since otherwise the queens will think themselves superior enough to play recklessly), meaning they will draw when they can successfully close the position completely.
SF-revised playing both sides?
Of course.
can we look at some of the games?
Sure. Here's a couple; I adjudicated the first.
[pgn]
[Event "Computer Chess Game"]
[Site "vivaine.local"]
[Date "2017.07.18"]
[Round "1"]
[White "Nightfish 180717 64"]
[Black "Nightfish 180717 64"]
[Result "1/2-1/2"]
[TimeControl "40/60"]
[FEN "nnnnknnn/pppppppp/8/8/8/8/PPPPPPPP/1Q1KQ1Q1 w - - 0 1"]
[SetUp "1"]
{--------------
n n n n k n n n
p p p p p p p p
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
P P P P P P P P
. Q . K Q . Q .
white to play
--------------}
1. f4 {+1.59/17} e6 {-1.29/16 2.1} 2. e4 {+1.39/20 2.0} Nhg6 {-1.28/17 1.4}
3. f5 {+1.29/15 0.6} N6e7 {-1.37/18 1.6} 4. b4 {+1.24/17 1.4} d6
{-1.42/15 0.3} 5. a4 {+1.09/18 4} Nbd7 {-1.34/16 1.7} 6. d3 {+1.28/16 1.2}
h6 {-1.14/16 1.2} 7. g4 {+1.13/17 2.7} Ngf6 {-1.25/18 1.6} 8. Qb2
{+1.29/17 1.3} g5 {-1.14/17 2.6} 9. Qg2 {+1.23/18 2.4} e5 {-1.01/18 4} 10.
Qh3 {+1.04/18 2.6} Neg8 {-0.95/17 1.0} 11. Kc1 {+1.03/18 1.2} c6
{-0.85/18 1.7} 12. Qhg3 {+0.88/18 4} Nc7 {-0.74/16 1.0} 13. c3
{+0.77/19 2.3} N8h7 {-0.69/18 2.3} 14. Qee2 {+0.75/18 4} b6 {-0.80/17 1.4}
15. d4 {+0.68/16 1.4} Kf8 {-0.63/17 0.9} 16. Qed3 {+0.89/18 1.9} h5
{-0.79/19 2.3} 17. h3 {+0.55/19 3} h4 {-0.63/16 0.6} 18. Qgh2
{+0.50/15 0.4} Nce8 {-0.60/15 0.5} 19. Qbc2 {+0.51/17 4} Nge7
{-0.08/17 1.9} 20. dxe5 {+0.38/17 1.7} Nxe5 {-1.16/21 2.7} 21. Qxe5
{+0.36/16 0.5} dxe5 {-1.05/20 0.7} 22. Qxd8 {+0.83/18 0.6} Kg7
{-1.10/21 1.4} 23. Qh2 {+1.14/18 0.5} Ned6 {-0.84/18 0.6} 24. Qxe5
{+0.98/17 0.6} Nxe4 {-1.14/22 2.8} 25. a5 {+1.24/19 1.0} Nf2 {-0.79/23 2.7}
26. Qe3 {+1.25/20 0.6} N2e4 {-0.84/24 1.1} 27. c4 {+1.25/21 0.8} c5
{-0.65/23 0.4} 28. bxc5 {+1.08/23 1.5} Nxc5 {-0.31/21 0.7} 29. axb6
{+1.05/23 0.6} axb6 {-0.16/24 1.9} 30. Qc3 {+0.98/21 0.5} Ne4
{-0.16/21 0.4} 31. Qa3 {+0.80/23 1.2} Nf8 {+0.00/22 0.8} 32. Qa1
{+0.20/20 1.0} Kg8 {+0.00/25 1.1} 33. Kd1 {+0.00/22 1.1} Nd7 {+0.00/28 1.1}
34. Qd4 {+0.00/24 0.6} Nec5 {+0.00/29 1.1} 35. Ke2 {+0.00/25 0.5} f6
{+0.00/29 0.6} 36. Qe8 {+0.00/23 0.4} Kg7 {+0.00/31 1.5} 37. Qd2
{+0.00/27 0.5} Ne4 {+0.00/29 1.3} 38. Qd3 {-0.07/29 1.3} Ned6
{+0.08/27 0.9} 39. Qxe7+ {-0.17/21 0.7} Nxe7 {+0.05/36 2.4} 40. Qxd6
{+0.00/22 0.6} Ng8 {+0.20/33 0.6} 41. Qc7 {-0.26/26 0.6} Nh6 {+0.00/37 4}
42. Qa7 {-0.08/34 1.2} Kf7 {+0.00/46 1.9} 43. Qb7 {-0.08/40 1.6} Kg7
{+0.14/40 3} 44. Kf2 {-0.08/38 1.8} Kh7 {+0.14/38 1.8} 45. Qc7
{-0.08/39 1.7} Nf7 {+0.00/38 2.6} 46. Ke2 {-0.08/40 1.9} Kg7 {+0.06/34 0.6}
47. Qa7 {-0.08/39 1.4} Nde5 {+0.08/39 5} 48. Qxb6 {-0.12/36 1.8} Nxc4
{+0.08/37 0.5} 49. Qb7 {-0.12/38 1.5} Ne5 {+0.08/33 1.5} 50. Qe7
{-0.14/34 2.7} Nfd7 {+0.39/33 3} 51. Qe8 {-0.11/35 1.6} Nc5 {+0.55/33 0.8}
52. Kf1 {-0.10/31 0.6} Nb7 {+0.55/35 0.6} 53. Qe7 {-0.42/39 10} Nd8
{+0.39/43 11} 54. Kg1 {-0.08/31 0.8} Nec6 {+0.60/34 5} 55. Qc5
{-0.35/38 2.5} Nb8 {+0.60/34 2.2} 56. Qd5 {-0.47/42 1.6} Ndc6
{+0.60/42 0.7} 57. Qe6 {-0.47/41 0.6} Nfe5 {+0.60/40 0.7} 58. Qe8
{-0.47/37 1.0} Na6 {+0.60/42 0.7} 59. Qc8 {-0.47/41 1.0} Nab8
{+0.60/41 0.4} 60. Kf2 {-0.47/41 0.9} Nbd7 {+0.60/43 0.7} 61. Qe8
{-0.47/39 0.6} Nc5 {+0.60/43 0.4} 62. Kf1 {-0.47/43 1.2} Ncd3
{+0.60/45 0.7} 63. Kg2 {-0.47/43 1.0} Nf4+ {+0.60/43 0.5} 64. Kh2
{-0.47/44 0.6} Nd5 {+0.60/45 0.8} 65. Kg2 {-0.47/38 1.2} Nce7
{+0.60/42 0.9} 66. Kg1 {-0.47/42 1.0} Nf3+ {+0.60/43 0.7} 67. Kf1
{-0.47/44 1.1} Ne5 {+0.60/36 0.7} 68. Kg2 {-0.47/40 1.1} N7c6
{+0.60/39 0.7} 69. Qc8 {-0.47/41 1.2} Nf4+ {+0.60/36 0.6} 70. Kh2
{-0.47/39 1.0} Kf7 {+0.60/39 1.0} 71. Qb7+ {-0.47/35 0.9} Ne7
{+0.60/40 0.7} 72. Qa8 {-0.47/35 0.6} N7c6 {+0.60/39 0.7} 73. Qb7+
{-0.47/37 2.3} Ne7 {+0.60/40 0.5} 74. Qa8 {-0.47/36 0.6} Nfd5 {+0.60/40 3}
75. Qd8 {-0.63/36 2.7} Nf3+ {+0.60/38 0.5} 76. Kg2 {-0.63/35 0.9} Ne5
{+0.60/38 0.4} 77. Kg1 {-0.63/36 1.0} N5c6 {+0.60/37 0.8} 78. Qh8
{-0.63/37 1.0} Ne5 {+0.60/36 0.5} 79. Qd8 {-0.63/36 0.3} Kg7 {+0.60/40 1.3}
80. Kh2 {-0.54/37 3} Nf3+ {+0.60/37 0.7} 81. Kg2 {-0.54/33 2.3} Ne5
{+0.59/35 1.7} 82. Qe8 {+0.00/29 2.5}
{User adjudication} 1/2-1/2
[/pgn]
[pgn][Event "Computer Chess Game"]
[Site "vivaine.local"]
[Date "2017.07.18"]
[Round "3"]
[White "Nightfish 180717 64"]
[Black "Nightfish 180717 64"]
[Result "0-1"]
[TimeControl "40/60"]
[FEN "nnnnknnn/pppppppp/8/8/8/8/PPPPPPPP/1Q1KQ1Q1 w - - 0 1"]
[SetUp "1"]
{--------------
n n n n k n n n
p p p p p p p p
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
P P P P P P P P
. Q . K Q . Q .
white to play
--------------}
1. f4 {+1.59/17} e6 {-1.60/17 2.1} 2. e4 {+1.39/20 2.0} Nhg6 {-1.36/16 0.6}
3. f5 {+1.29/15 0.5} N6e7 {-1.33/18 1.7} 4. b4 {+1.24/17 1.4} d6
{-1.41/15 0.5} 5. a4 {+1.09/18 4} Nbd7 {-1.28/16 0.8} 6. d3 {+1.28/16 1.2}
b6 {-1.02/17 3} 7. c3 {+1.20/17 2.2} c5 {-1.08/18 3} 8. g4 {+1.09/17 1.6}
e5 {-1.03/19 3} 9. b5 {+1.08/17 1.3} Nc7 {-0.88/21 4} 10. c4 {+1.03/19 1.3}
Ngf6 {-0.91/20 1.1} 11. Qa2 {+0.74/21 7} Nb7 {-0.84/20 0.8} 12. Qae2
{+0.57/19 2.6} h6 {-0.65/18 0.6} 13. h4 {+0.42/18 1.4} g6 {-0.82/15 0.4}
14. g5 {+0.13/22 6} Nh5 {-0.35/15 0.6} 15. Qf3 {+0.00/22 3} Na5
{+0.02/16 0.7} 16. gxh6 {-0.13/17 1.0} Nhf6 {+0.34/17 0.7} 17. Qgg3
{-0.12/17 0.9} gxf5 {+0.68/19 2.8} 18. exf5 {-0.26/17 1.2} Nb3
{+0.70/15 0.5} 19. a5 {-0.53/20 4} Kd8 {+0.87/17 2.0} 20. Qg7
{+0.04/14 0.4} Nd4 {+0.92/18 2.1} 21. Qff2 {-0.87/16 2.1} d5 {+1.28/18 3}
22. axb6 {-1.34/17 3} axb6 {+1.62/17 1.3} 23. Qxf7 {-1.04/17 1.5} Nd6
{+1.87/17 0.9} 24. Qg7 {-1.46/16 1.2} N6xf5 {+1.83/17 0.6} 25. Qgg1
{-1.46/16 0.8} Nfe6 {+1.83/19 2.8} 26. h7 {-1.82/17 1.2} Nxh7
{+1.90/19 0.6} 27. Kc1 {-1.77/14 0.5} Nf4 {+1.75/17 0.4} 28. Qef1
{-1.75/16 0.6} Nhf6 {+1.93/17 0.9} 29. Kb2 {-1.89/15 0.5} Kc8
{+2.07/17 0.9} 30. Qfh2 {-1.54/14 0.4} Nd6 {+2.28/19 2.2} 31. h5
{-1.77/14 0.6} N4xh5 {+2.76/19 3} 32. Ka1 {-2.02/14 0.6} Nef5
{+3.06/17 1.0} 33. Qd1 {-1.60/10 0.5} Nf4 {+3.56/16 1.0} 34. Qa2
{-1.85/10 0.6} dxc4 {+3.94/16 0.6} 35. dxc4 {-1.58/11 0.6} e4
{+4.51/16 0.6} 36. Qgh2 {-2.99/10 0.4} Nd3 {+4.41/15 0.6} 37. Qdd2
{-3.28/10 0.6} N7e5 {+6.10/16 0.7} 38. Qdg2 {-4.26/9 0.6} Nexc4
{+6.94/17 1.8} 39. Qa4 {-4.40/10 0.5} Na5 {+7.66/16 0.9} 40. Qga2
{-5.80/10 0.6} c4 {+8.99/18 2.0} 41. Qh8+ {-9.60/18 4} Nfe8 {+9.90/19 1.6}
42. Qh7 {-11.45/22 14} Ncxb5 {+11.76/19 1.9} 43. Qb2 {-13.92/23 3} Ndb3+
{+13.84/18 1.5} 44. Kb1 {-16.80/21 4} Nfd4 {+14.84/18 0.6} 45. Qaa2
{-20.08/23 7} Kb8 {+23.96/20 2.8} 46. Qh4 {-64.19/22 4} Nxb2
{+99.53/23 2.4} 47. Qxb2 {-99.58/21 1.6} c3 {+99.65/27 1.3} 48. Qa2
{-99.62/23 0.9} c2+ {+99.73/31 1.4} 49. Qxc2 {-99.72/29 0.7} Na3+
{+99.75/31 0.4} 50. Ka2 {-99.74/29 0.6} Naxc2 {+99.79/37 1.4} 51. Qd8+
{-99.80/32 0.8} Ka7 {+99.81/35 0.6} 52. Qd7+ {-99.82/35 0.6} Ka6
{+99.83/42 1.5} 53. Qd8 {-99.84/35 0.8} Nb4+ {+99.85/41 0.4} 54. Kb1
{-99.86/36 0.6} Ne2 {+99.87/49 1.6} 55. Qa8+ {-99.88/44 0.6} Kb5
{+99.89/1 0.5} 56. Qc8 {-99.90/48 0.6} Nd2+ {+99.91/65 1.4} 57. Ka1
{-99.92/53 0.6} Nxc8 {+99.93/68 0.4} 58. Kb2 {-99.94/1 0.6} Nac4+
{+99.95/127 0.6} 59. Ka1 {-99.96/1 0.6} Nb3+ {+99.97/127 0.6} 60. Kb1
{-99.98/1 0.6} Nc3# {+99.99/127 0.4}
{Xboard adjudication: Checkmate} 0-1[/pgn]