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Slightly improved mobility evaluation. Improved performance of the ev…
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…aluation function.
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@Dannyj1
Dannyj1 committed Jan 9, 2023
1 parent 8e99649 commit 8b708db
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Showing 4 changed files with 38 additions and 49 deletions.
1 change: 1 addition & 0 deletions move_gen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,7 @@ namespace Zagreus {
return moves;
}

// TODO: different faster moe
bool sortMoves(Bitboard &bitboard, Move &a, Move &b) {
// TODO: implement countermoves heuristic. Need to have previousMoveFrom available in this function.
int aScore = tt.historyMoves[a.pieceType][a.toSquare];
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74 changes: 30 additions & 44 deletions search_mgr.cpp
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Expand Up @@ -370,9 +370,6 @@ namespace Zagreus {
whiteScore += getWhiteRookScore(board);
blackScore += getBlackRookScore(board);

whiteScore += getCenterScore(board, PieceColor::WHITE);
blackScore += getCenterScore(board, PieceColor::BLACK);

whiteScore += getWhiteDevelopmentScore(board);
blackScore += getBlackDevelopmentScore(board);

Expand Down Expand Up @@ -573,35 +570,6 @@ namespace Zagreus {
return score;
}

int SearchManager::getCenterScore(Bitboard &bitboard, PieceColor color) {
int score = 0;
uint64_t centerPattern = 0x0000001818000000;
uint64_t extendedCenterPattern = 0x00003C3C3C3C0000 & ~centerPattern;

while (centerPattern) {
uint64_t index = bitscanForward(centerPattern);
PieceType pieceOnSquare = bitboard.getPieceOnSquare(index);
uint64_t attacks = bitboard.getSquareAttacksByColor(index, color);

if (pieceOnSquare != PieceType::EMPTY && bitboard.getPieceColor(pieceOnSquare) == color) {
score += 15;
}

score += popcnt(attacks) * 7;
centerPattern = _blsr_u64(centerPattern);
}

while (extendedCenterPattern) {
uint64_t index = bitscanForward(extendedCenterPattern);
uint64_t attacks = bitboard.getSquareAttacksByColor(index, color);

score += popcnt(attacks) * 4;
extendedCenterPattern = _blsr_u64(extendedCenterPattern);
}

return score;
}

uint64_t whiteMinorPiecesStartBB = 0x66ULL;
uint64_t whiteRookStartBB = 0x81ULL;
uint64_t whiteQueenStartBB = 0x10ULL;
Expand Down Expand Up @@ -736,17 +704,22 @@ namespace Zagreus {
return score;
}

uint64_t centerPattern = 0x0000001818000000;
uint64_t extendedCenterPattern = 0x00003C3C3C3C0000 & ~centerPattern;
int SearchManager::getMobilityScore(Bitboard &bitboard, PieceColor color) {
int score = 0;
uint64_t ownPiecesBB = bitboard.getBoardByColor(color);
uint64_t opponentPawnBB = bitboard.getPieceBoard(PieceType::WHITE_PAWN + Bitboard::getOppositeColor(color));
uint64_t opponentPawnAttacks = bitboard.calculatePawnAttacks(opponentPawnBB, Bitboard::getOppositeColor(color));
uint64_t pawnBB = bitboard.getPieceBoard(PieceType::WHITE_PAWN + color);
uint64_t knightBB = bitboard.getPieceBoard(PieceType::WHITE_KNIGHT + color);
uint64_t bishopBB = bitboard.getPieceBoard(PieceType::WHITE_BISHOP + color);
uint64_t rookBB = bitboard.getPieceBoard(PieceType::WHITE_ROOK + color);
uint64_t queenBB = bitboard.getPieceBoard(PieceType::WHITE_QUEEN + color);
uint64_t kingBB = bitboard.getPieceBoard(PieceType::WHITE_KING + color);

uint64_t knightAttacks = calculateKnightAttacks(knightBB) & ~ownPiecesBB;
uint64_t pawnAttacks = bitboard.calculatePawnAttacks(pawnBB, color);
uint64_t knightAttacks = calculateKnightAttacks(knightBB);
uint64_t bishopAttacks = 0;
uint64_t rookAttacks = 0;
uint64_t queenAttacks = 0;
Expand All @@ -757,7 +730,7 @@ namespace Zagreus {
uint64_t index = bitscanForward(bishopBB);

if (!bitboard.isPinned(index, color)) {
bishopAttacks |= bitboard.getBishopAttacks(index, occupied) & ~ownPiecesBB;
bishopAttacks |= bitboard.getBishopAttacks(index, occupied);
}

bishopBB &= ~(1ULL << index);
Expand All @@ -767,7 +740,7 @@ namespace Zagreus {
uint64_t index = bitscanForward(rookBB);

if (!bitboard.isPinned(index, color)) {
rookAttacks |= bitboard.getRookAttacks(index, occupied) & ~ownPiecesBB;
rookAttacks |= bitboard.getRookAttacks(index, occupied);
}

rookBB &= ~(1ULL << index);
Expand All @@ -777,7 +750,7 @@ namespace Zagreus {
uint64_t index = bitscanForward(queenBB);

if (!bitboard.isPinned(index, color)) {
queenAttacks |= bitboard.getQueenAttacks(index, occupied) & ~ownPiecesBB;
queenAttacks |= bitboard.getQueenAttacks(index, occupied);
}

queenBB &= ~(1ULL << index);
Expand All @@ -787,17 +760,30 @@ namespace Zagreus {
bishopAttacks &= ~opponentPawnAttacks;
rookAttacks &= ~opponentPawnAttacks;
queenAttacks &= ~opponentPawnAttacks;
pawnAttacks &= ~opponentPawnAttacks;
uint64_t combinedAttacks = knightAttacks | bishopAttacks | rookAttacks | queenAttacks | pawnAttacks;

// Center score
score += popcnt(combinedAttacks & centerPattern) * 10;
score += popcnt(combinedAttacks & extendedCenterPattern) * 5;
score += popcnt(ownPiecesBB & centerPattern) * 4;
score += popcnt(ownPiecesBB & extendedCenterPattern) * 2;
// Slight bonus for squares defended by own pawn
score += popcnt(combinedAttacks & pawnAttacks);

// Connectivity score
score += popcnt(combinedAttacks & ownPiecesBB);

if (bitboard.getFullmoveClock() > 12) {
score += popcnt(knightAttacks) * 2;
score += popcnt(bishopAttacks) * 2;
score += popcnt(rookAttacks) * 5;
score += popcnt(queenAttacks) * 7;
score += popcnt(knightAttacks & ~ownPiecesBB) * 2;
score += popcnt(bishopAttacks & ~ownPiecesBB) * 2;
score += popcnt(rookAttacks & ~ownPiecesBB) * 5;
score += popcnt(queenAttacks & ~ownPiecesBB) * 7;
} else {
score += popcnt(knightAttacks) * 5;
score += popcnt(bishopAttacks) * 5;
score += popcnt(rookAttacks);
score += popcnt(queenAttacks) * 2;
score += popcnt(knightAttacks & ~ownPiecesBB) * 5;
score += popcnt(bishopAttacks & ~ownPiecesBB) * 5;
score += popcnt(rookAttacks & ~ownPiecesBB);
score += popcnt(queenAttacks & ~ownPiecesBB) * 2;
}

return score;
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2 changes: 0 additions & 2 deletions search_mgr.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,8 +52,6 @@ namespace Zagreus {

int getBlackBishopScore(Bitboard &bitboard);

int getCenterScore(Bitboard &bitboard, PieceColor color);

int getWhiteDevelopmentScore(Bitboard &bitboard);

int getBlackDevelopmentScore(Bitboard &bitboard);
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10 changes: 7 additions & 3 deletions time_mgr.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,14 +12,14 @@ namespace Zagreus {
int movesLeft = 90 - bitboard.getPly();
uint64_t timeLeft =
movingColor == PieceColor::WHITE ? bitboard.getWhiteTimeMsec() : bitboard.getBlackTimeMsec();
timeLeft -= 200;
timeLeft -= 100;
uint64_t increment =
movingColor == PieceColor::WHITE ? bitboard.getWhiteTimeIncrement() : bitboard.getBlackTimeIncrement();

timeLeft += increment / 2;

if (movesLeft < 6) {
movesLeft = 6;
if (movesLeft < 7) {
movesLeft = 7;
}

if (timeLeft == 0) {
Expand All @@ -32,6 +32,10 @@ namespace Zagreus {
timePerMove *= 2;
}

if (bitboard.getPly() >= 40) {
timePerMove /= 2;
}

std::chrono::time_point<std::chrono::high_resolution_clock> now = std::chrono::high_resolution_clock::now();
now += std::chrono::milliseconds(timePerMove);
return now;
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