PeSTO's Evaluation Function

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PeSTO's Evaluation Function, a Piece-Square Tables Only evaluation function by Ronald Friederich as tried in his chess engine RofChade further used in his experimental chess engine PeSTO. It performs a tapered evaluation to interpolate by current game stage between piece-square tables values for opening and endgame, optimized by Texel's tuning method. Pesto's Evaluation Function is intended to replace Tomasz Michniewski's Simplified Evaluation Function, and was successfully applied in several engines. Maksim Korzh used and adapted Pesto's Evaluation Function in Wukong JS along with his own Texel's tuning trials. Pawel Koziol gave TSCP by Tom Kerrigan an 200 Elo boost with Pesto's Evaluation Function, further tried by Ed Schröder in ProDeo.

=Source Code= PeSTO's Evaluation Function based on Pawel Koziol's implementation in TSCP by Tom Kerrigan
 * 1) define PAWN  0
 * 2) define KNIGHT 1
 * 3) define BISHOP 2
 * 4) define ROOK  3
 * 5) define QUEEN 4
 * 6) define KING  5

/* board representation */
 * 1) define WHITE 0
 * 2) define BLACK 1


 * 1) define WHITE_PAWN     (2*PAWN   + WHITE)
 * 2) define BLACK_PAWN     (2*PAWN   + BLACK)
 * 3) define WHITE_KNIGHT   (2*KNIGHT + WHITE)
 * 4) define BLACK_KNIGHT   (2*KNIGHT + BLACK)
 * 5) define WHITE_BISHOP   (2*BISHOP + WHITE)
 * 6) define BLACK_BISHOP   (2*BISHOP + BLACK)
 * 7) define WHITE_ROOK     (2*ROOK   + WHITE)
 * 8) define BLACK_ROOK     (2*ROOK   + BLACK)
 * 9) define WHITE_QUEEN    (2*QUEEN  + WHITE)
 * 10) define BLACK_QUEEN    (2*QUEEN  + BLACK)
 * 11) define WHITE_KING     (2*KING   + WHITE)
 * 12) define BLACK_KING     (2*KING   + BLACK)
 * 13) define EMPTY          (BLACK_KING  +  1)


 * 1) define PCOLOR(p) ((p)&1)

int side2move; int board[64];


 * 1) define FLIP(sq) ((sq)^56)
 * 2) define OTHER(side) ((side)^ 1)

int mg_value[6] = { 82, 337, 365, 477, 1025, 0}; int eg_value[6] = { 94, 281, 297, 512, 936,  0};

/* piece/sq tables */ /* values from Rofchade: http://www.talkchess.com/forum3/viewtopic.php?f=2&t=68311&start=19 */

int mg_pawn_table[64] = { 0,  0,   0,   0,   0,   0,  0,   0,     98, 134,  61,  95,  68, 126, 34, -11,     -6,   7,  26,  31,  65,  56, 25, -20,    -14,  13,   6,  21,  23,  12, 17, -23,    -27,  -2,  -5,  12,  17,   6, 10, -25,    -26,  -4,  -4, -10,   3,   3, 33, -12,    -35,  -1, -20, -23, -15,  24, 38, -22,      0,   0,   0,   0,   0,   0,  0,   0, };

int eg_pawn_table[64] = { 0,  0,   0,   0,   0,   0,   0,   0,    178, 173, 158, 134, 147, 132, 165, 187,     94, 100,  85,  67,  56,  53,  82,  84,     32,  24,  13,   5,  -2,   4,  17,  17,     13,   9,  -3,  -7,  -7,  -8,   3,  -1,      4,   7,  -6,   1,   0,  -5,  -1,  -8,     13,   8,   8,  10,  13,   0,   2,  -7,      0,   0,   0,   0,   0,   0,   0,   0, };

int mg_knight_table[64] = { -167, -89, -34, -49, 61, -97, -15, -107,     -73, -41,  72,  36,  23,  62,   7,  -17,     -47,  60,  37,  65,  84, 129,  73,   44,      -9,  17,  19,  53,  37,  69,  18,   22,     -13,   4,  16,  13,  28,  19,  21,   -8,     -23,  -9,  12,  10,  19,  17,  25,  -16,     -29, -53, -12,  -3,  -1,  18, -14,  -19,    -105, -21, -58, -33, -17, -28, -19,  -23, };

int eg_knight_table[64] = { -58, -38, -13, -28, -31, -27, -63, -99,   -25,  -8, -25,  -2,  -9, -25, -24, -52,    -24, -20,  10,   9,  -1,  -9, -19, -41,    -17,   3,  22,  22,  22,  11,   8, -18,    -18,  -6,  16,  25,  16,  17,   4, -18,    -23,  -3,  -1,  15,  10,  -3, -20, -22,    -42, -20, -10,  -5,  -2, -20, -23, -44,    -29, -51, -23, -15, -22, -18, -50, -64, };

int mg_bishop_table[64] = { -29,  4, -82, -37, -25, -42,   7,  -8,    -26,  16, -18, -13,  30,  59,  18, -47,    -16,  37,  43,  40,  35,  50,  37,  -2,     -4,   5,  19,  50,  37,  37,   7,  -2,     -6,  13,  13,  26,  34,  12,  10,   4,      0,  15,  15,  15,  14,  27,  18,  10,      4,  15,  16,   0,   7,  21,  33,   1,    -33,  -3, -14, -21, -13, -12, -39, -21, };

int eg_bishop_table[64] = { -14, -21, -11, -8, -7,  -9, -17, -24,     -8,  -4,   7, -12, -3, -13,  -4, -14,      2,  -8,   0,  -1, -2,   6,   0,   4,     -3,   9,  12,   9, 14,  10,   3,   2,     -6,   3,  13,  19,  7,  10,  -3,  -9,    -12,  -3,   8,  10, 13,   3,  -7, -15,    -14, -18,  -7,  -1,  4,  -9, -15, -27,    -23,  -9, -23,  -5, -9, -16,  -5, -17, };

int mg_rook_table[64] = { 32, 42,  32,  51, 63,  9,  31,  43,     27,  32,  58,  62, 80, 67,  26,  44,     -5,  19,  26,  36, 17, 45,  61,  16,    -24, -11,   7,  26, 24, 35,  -8, -20,    -36, -26, -12,  -1,  9, -7,   6, -23,    -45, -25, -16, -17,  3,  0,  -5, -33,    -44, -16, -20,  -9, -1, 11,  -6, -71,    -19, -13,   1,  17, 16,  7, -37, -26, };

int eg_rook_table[64] = { 13, 10, 18, 15, 12, 12,   8,   5,    11, 13, 13, 11, -3,   3,   8,   3,     7,  7,  7,  5,  4,  -3,  -5,  -3,     4,  3, 13,  1,  2,   1,  -1,   2,     3,  5,  8,  4, -5,  -6,  -8, -11,    -4,  0, -5, -1, -7, -12,  -8, -16,    -6, -6,  0,  2, -9,  -9, -11,  -3,    -9,  2,  3, -1, -5, -13,   4, -20, };

int mg_queen_table[64] = { -28,  0,  29,  12,  59,  44,  43,  45,    -24, -39,  -5,   1, -16,  57,  28,  54,    -13, -17,   7,   8,  29,  56,  47,  57,    -27, -27, -16, -16,  -1,  17,  -2,   1,     -9, -26,  -9, -10,  -2,  -4,   3,  -3,    -14,   2, -11,  -2,  -5,   2,  14,   5,    -35,  -8,  11,   2,   8,  15,  -3,   1,     -1, -18,  -9,  10, -15, -25, -31, -50, };

int eg_queen_table[64] = { -9, 22,  22,  27,  27,  19,  10,  20,    -17,  20,  32,  41,  58,  25,  30,   0,    -20,   6,   9,  49,  47,  35,  19,   9,      3,  22,  24,  45,  57,  40,  57,  36,    -18,  28,  19,  47,  31,  34,  39,  23,    -16, -27,  15,   6,   9,  17,  10,   5,    -22, -23, -30, -16, -16, -23, -36, -32,    -33, -28, -22, -43,  -5, -32, -20, -41, };

int mg_king_table[64] = { -65, 23,  16, -15, -56, -34,   2,  13,     29,  -1, -20,  -7,  -8,  -4, -38, -29,     -9,  24,   2, -16, -20,   6,  22, -22,    -17, -20, -12, -27, -30, -25, -14, -36,    -49,  -1, -27, -39, -46, -44, -33, -51,    -14, -14, -22, -46, -44, -30, -15, -27,      1,   7,  -8, -64, -43, -16,   9,   8,    -15,  36,  12, -54,   8, -28,  24,  14, };

int eg_king_table[64] = { -74, -35, -18, -18, -11, 15,   4, -17,    -12,  17,  14,  17,  17,  38,  23,  11,     10,  17,  23,  15,  20,  45,  44,  13,     -8,  22,  24,  27,  26,  33,  26,   3,    -18,  -4,  21,  24,  27,  23,   9, -11,    -19,  -3,  11,  21,  23,  16,   7,  -9,    -27, -11,   4,  13,  14,   4,  -5, -17,    -53, -34, -21, -11, -28, -14, -24, -43 };

int* mg_pesto_table[6] = {   mg_pawn_table, mg_knight_table, mg_bishop_table, mg_rook_table, mg_queen_table, mg_king_table };

int* eg_pesto_table[6] = {   eg_pawn_table, eg_knight_table, eg_bishop_table, eg_rook_table, eg_queen_table, eg_king_table };

int gamephaseInc[12] = {0,0,1,1,1,1,2,2,4,4,0,0}; int mg_table[12][64]; int eg_table[12][64];

void init_tables {   int pc, p, sq; for (p = PAWN, pc = WHITE_PAWN; p <= KING; pc += 2, p++) { for (sq = 0; sq < 64; sq++) { mg_table[pc] [sq] = mg_value[p] + mg_pesto_table[p][sq]; eg_table[pc] [sq] = eg_value[p] + eg_pesto_table[p][sq]; mg_table[pc+1][sq] = mg_value[p] + mg_pesto_table[p][FLIP(sq)]; eg_table[pc+1][sq] = eg_value[p] + eg_pesto_table[p][FLIP(sq)]; }   } }

int eval {   int mg[2]; int eg[2]; int gamePhase = 0;

mg[WHITE] = 0; mg[BLACK] = 0; eg[WHITE] = 0; eg[BLACK] = 0;

/* evaluate each piece */ for (int sq = 0; sq < 64; ++sq) { int pc = board[sq]; if (pc != EMPTY) { mg[PCOLOR(pc)] += mg_table[pc][sq]; eg[PCOLOR(pc)] += eg_table[pc][sq]; gamePhase += gamephaseInc[pc]; }   }

/* tapered eval */ int mgScore = mg[side2move] - mg[OTHER(side2move)]; int egScore = eg[side2move] - eg[OTHER(side2move)]; int mgPhase = gamePhase; if (mgPhase > 24) mgPhase = 24; /* in case of early promotion */ int egPhase = 24 - mgPhase; return (mgScore * mgPhase + egScore * egPhase) / 24; } =See also=
 * PeSTO
 * Piece-Square Tables
 * ProDeo
 * RofChade
 * Simplified Evaluation Function
 * Tapered Eval
 * TSCP
 * Wukong JS

=Forum Posts=
 * Re: New uci engine: Rofchade by Ronald Friederich, CCC, Auguat 28, 2018
 * Re: Help with Texel's tuning by Maksim Korzh, CCC, January 07, 2021
 * little fun with TSCP by nescitus, ProDeo Forum, February 12, 2021
 * ProDeo 3.1 - The PESTO version by Ed Schröder, ProDeo Forum, February 19, 2021
 * ProDeo 3.1 - The PESTO version by Ed Schröder, CCC, February 19, 2021
 * Re: Hitting a wall at ~1860 Elo by Erik Madsen, CCC, June 02, 2021
 * Game Phase and tapered PSQT evaluation by Jon12345, CCC, June 23, 2021

=External Links=
 * PeSTO: Piece Square Tables Only – RofChade
 * wukongJS/wukong.js at main · maksimKorzh/wukongJS · GitHub by Maksim Korzh » Wukong JS
 * Community - Tom Kerrigan's Home Page » TSCP
 * ProDeo 3.1 | The PeSTO Version » ProDeo

=References= Up one Level