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Winnable, STC pass! #192

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Merged
ProgramciDusunur merged 2 commits into from
Feb 1, 2025
Merged

Winnable, STC pass! #192

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93f3c1e
add winnable heuristic
ProgramciDusunur Feb 1, 2025
7267114
bench: 10738152
ProgramciDusunur Feb 1, 2025
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20 changes: 20 additions & 0 deletions src/evaluation.c
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Original file line number Diff line number Diff line change
Expand Up @@ -276,6 +276,9 @@ int evaluate(board* position) {
// penalties
//int double_pawns = 0;

// passer pawn count
int passedPawnCount = 0;

// loop over piece bitboards
for (int bb_piece = P; bb_piece <= k; bb_piece++) {
// init piece bitboard copy
Expand Down Expand Up @@ -351,6 +354,7 @@ int evaluate(board* position) {
if ((whitePassedMasks[square] & position->bitboards[p]) == 0) {
// give passed pawn bonus
if (game_phase == endgame) {
passedPawnCount += 1;

int whiteKingDistance = (getLS1BIndex(position->bitboards[K]) - square) / 8;
int blackKingDistance = (getLS1BIndex(position->bitboards[k]) - square) / 8;
Expand Down Expand Up @@ -508,6 +512,8 @@ int evaluate(board* position) {
if ((blackPassedMasks[square] & position->bitboards[P]) == 0) {
// give passed pawn bonus
if (game_phase == endgame) {
passedPawnCount -= 1;

int whiteKingDistance = (getLS1BIndex(position->bitboards[K]) - square) / 8;
int blackKingDistance = (getLS1BIndex(position->bitboards[k]) - square) / 8;
int kingDistance = whiteKingDistance - blackKingDistance;
Expand Down Expand Up @@ -631,6 +637,20 @@ int evaluate(board* position) {
popBit(bitboard, square);
}
}

int infiltriation = 0;
if (!position->side && get_rank[getLS1BIndex(position->bitboards[K])] > 5) {
infiltriation = 20;
} else if (position->side && get_rank[getLS1BIndex(position->bitboards[k])] < 2) {
infiltriation = -20;
}
// winnable
int winnableScore = 6 * passedPawnCount +
8 * (countBits(position->bitboards[P]) - countBits(position->bitboards[p])) +
infiltriation
;
score += winnableScore;

int tempo = 10;
// return final evaluation based on side
return (position->side == white) ? score + tempo : -(score - tempo);
Expand Down