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Merged
eugenioenko merged 1 commit into from
Feb 17, 2026
Merged

feat: evaluate pset #19

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211 changes: 158 additions & 53 deletions pkg/const.go
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Original file line number Diff line number Diff line change
Expand Up @@ -236,64 +236,169 @@ var BlackPromotionMap = map[byte]byte{
'n': BlackKnight,
}

// Piece-Square Tables (simplified, values in centipawns)
var pawnPST = [64]int{
// Game phase weights for tapered evaluation
const (
PawnPhase = 0
KnightPhase = 1
BishopPhase = 1
RookPhase = 2
QueenPhase = 4
TotalPhase = 24 // 4*1(knights) + 4*1(bishops) + 4*2(rooks) + 2*4(queens)
)

// PeSTO base material values (added to PST in init)
var mgPieceValue = [6]int{82, 337, 365, 477, 1025, 0} // pawn, knight, bishop, rook, queen, king
var egPieceValue = [6]int{94, 281, 297, 512, 936, 0}

// PeSTO Piece-Square Tables (positional component, material added in init)
// Indexed from white's perspective: a8=0, h1=63

// Middlegame tables
var mgPawnPST = [64]int{
0, 0, 0, 0, 0, 0, 0, 0,
50, 50, 50, 50, 50, 50, 50, 50,
10, 10, 20, 30, 30, 20, 10, 10,
5, 5, 10, 25, 25, 10, 5, 5,
0, 0, 0, 20, 20, 0, 0, 0,
5, -5, -10, 0, 0, -10, -5, 5,
5, 10, 10, -20, -20, 10, 10, 5,
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,
}
var knightPST = [64]int{
-50, -40, -30, -30, -30, -30, -40, -50,
-40, -20, 0, 0, 0, 0, -20, -40,
-30, 0, 10, 15, 15, 10, 0, -30,
-30, 5, 15, 20, 20, 15, 5, -30,
-30, 0, 15, 20, 20, 15, 0, -30,
-30, 5, 10, 15, 15, 10, 5, -30,
-40, -20, 0, 5, 5, 0, -20, -40,
-50, -40, -30, -30, -30, -30, -40, -50,
var egPawnPST = [64]int{
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,
}
var bishopPST = [64]int{
-20, -10, -10, -10, -10, -10, -10, -20,
-10, 5, 0, 0, 0, 0, 5, -10,
-10, 10, 10, 10, 10, 10, 10, -10,
-10, 0, 10, 10, 10, 10, 0, -10,
-10, 5, 5, 10, 10, 5, 5, -10,
-10, 0, 5, 10, 10, 5, 0, -10,
-10, 0, 0, 0, 0, 0, 0, -10,
-20, -10, -10, -10, -10, -10, -10, -20,

var mgKnightPST = [64]int{
-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,
}
var rookPST = [64]int{
0, 0, 0, 0, 0, 0, 0, 0,
5, 10, 10, 10, 10, 10, 10, 5,
-5, 0, 0, 0, 0, 0, 0, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
0, 0, 0, 5, 5, 0, 0, 0,
var egKnightPST = [64]int{
-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,
}

var mgBishopPST = [64]int{
-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,
}
var queenPST = [64]int{
-20, -10, -10, -5, -5, -10, -10, -20,
-10, 0, 0, 0, 0, 0, 0, -10,
-10, 0, 5, 5, 5, 5, 0, -10,
-5, 0, 5, 5, 5, 5, 0, -5,
0, 0, 5, 5, 5, 5, 0, -5,
-10, 5, 5, 5, 5, 5, 0, -10,
-10, 0, 5, 0, 0, 0, 0, -10,
-20, -10, -10, -5, -5, -10, -10, -20,
var egBishopPST = [64]int{
-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,
}
var kingPST = [64]int{
-30, -40, -40, -50, -50, -40, -40, -30,
-30, -40, -40, -50, -50, -40, -40, -30,
-30, -40, -40, -50, -50, -40, -40, -30,
-30, -40, -40, -50, -50, -40, -40, -30,
-20, -30, -30, -40, -40, -30, -30, -20,
-10, -20, -20, -20, -20, -20, -20, -10,
20, 20, 0, 0, 0, 0, 20, 20,
20, 30, 10, 0, 0, 10, 30, 20,

var mgRookPST = [64]int{
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,
}
var egRookPST = [64]int{
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,
}

var mgQueenPST = [64]int{
-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,
}
var egQueenPST = [64]int{
-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,
}

var mgKingPST = [64]int{
-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,
}
var egKingPST = [64]int{
-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,
}

func init() {
// Bake material values into PST tables
type pstPair struct {
mg *[64]int
eg *[64]int
piece int // index into mgPieceValue/egPieceValue
}
pairs := []pstPair{
{&mgPawnPST, &egPawnPST, 0},
{&mgKnightPST, &egKnightPST, 1},
{&mgBishopPST, &egBishopPST, 2},
{&mgRookPST, &egRookPST, 3},
{&mgQueenPST, &egQueenPST, 4},
{&mgKingPST, &egKingPST, 5},
}
for _, p := range pairs {
for sq := 0; sq < 64; sq++ {
p.mg[sq] += mgPieceValue[p.piece]
p.eg[sq] += egPieceValue[p.piece]
}
}
}
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