non-pawn corrhist (#476)

Elo   | 6.98 +- 3.56 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=16MB
LLR   | 2.91 (-2.25, 2.89) [0.00, 3.00]
Games | N: 9812 W: 2462 L: 2265 D: 5085
Penta | [21, 1120, 2446, 1279, 40]

Elo   | 12.28 +- 4.75 (95%)
SPRT  | 40.0+0.40s Threads=1 Hash=64MB
LLR   | 2.89 (-2.25, 2.89) [0.00, 3.00]
Games | N: 4980 W: 1213 L: 1037 D: 2730
Penta | [1, 512, 1292, 680, 5]

Bench: 6558838

src/history.cpp

@@ -116,19 +116,29 @@ int GetCapthistScore(const Position* pos, const SearchData* sd, const Move move)
     return sd->captHist[PieceTo(move)][capturedPiece];
 }
 
+void updateSingleCorrHistScore(int &entry, const int scaledDiff, const int newWeight) {
+    entry = (entry * (CORRHIST_WEIGHT_SCALE - newWeight) + scaledDiff * newWeight) / CORRHIST_WEIGHT_SCALE;
+    entry = std::clamp(entry, -CORRHIST_MAX, CORRHIST_MAX);
+}
+
 void updateCorrHistScore(const Position *pos, SearchData *sd, const int depth, const int diff) {
-    int &entry = sd->corrHist[pos->side][pos->pawnKey % CORRHIST_SIZE];
     const int scaledDiff = diff * CORRHIST_GRAIN;
     const int newWeight = std::min(depth * depth + 2 * depth + 1, 128);
     assert(newWeight <= CORRHIST_WEIGHT_SCALE);
 
-    entry = (entry * (CORRHIST_WEIGHT_SCALE - newWeight) + scaledDiff * newWeight) / CORRHIST_WEIGHT_SCALE;
-    entry = std::clamp(entry, -CORRHIST_MAX, CORRHIST_MAX);
+    updateSingleCorrHistScore(sd->pawnCorrHist[pos->side][pos->pawnKey % CORRHIST_SIZE], scaledDiff, newWeight);
+    updateSingleCorrHistScore(sd->whiteNonPawnCorrHist[pos->side][pos->whiteNonPawnKey % CORRHIST_SIZE], scaledDiff, newWeight);
+    updateSingleCorrHistScore(sd->blackNonPawnCorrHist[pos->side][pos->blackNonPawnKey % CORRHIST_SIZE], scaledDiff, newWeight);
 }
 
 int adjustEvalWithCorrHist(const Position *pos, const SearchData *sd, const int rawEval) {
-    const int &entry = sd->corrHist[pos->side][pos->pawnKey % CORRHIST_SIZE];
-    return std::clamp(rawEval + entry / CORRHIST_GRAIN, -MATE_FOUND + 1, MATE_FOUND - 1);
+    int adjustedEval = rawEval;
+
+    adjustedEval += sd->pawnCorrHist[pos->side][pos->pawnKey % CORRHIST_SIZE] / CORRHIST_GRAIN;
+    adjustedEval += sd->whiteNonPawnCorrHist[pos->side][pos->whiteNonPawnKey % CORRHIST_SIZE] / CORRHIST_GRAIN;
+    adjustedEval += sd->blackNonPawnCorrHist[pos->side][pos->blackNonPawnKey % CORRHIST_SIZE] / CORRHIST_GRAIN;
+
+    return std::clamp(adjustedEval, -MATE_FOUND + 1, MATE_FOUND - 1);
 }
 
 int GetHistoryScore(const Position* pos, const SearchData* sd, const Move move, const SearchStack* ss, const bool rootNode) {
@@ -144,5 +154,7 @@ void CleanHistories(SearchData* sd) {
     std::memset(sd->rootHistory, 0, sizeof(sd->rootHistory));
     std::memset(sd->contHist, 0, sizeof(sd->contHist));
     std::memset(sd->captHist, 0, sizeof(sd->captHist));
-    std::memset(sd->corrHist, 0, sizeof(sd->corrHist));
+    std::memset(sd->pawnCorrHist, 0, sizeof(sd->pawnCorrHist));
+    std::memset(sd->whiteNonPawnCorrHist, 0, sizeof(sd->whiteNonPawnCorrHist));
+    std::memset(sd->blackNonPawnCorrHist, 0, sizeof(sd->blackNonPawnCorrHist));
 }

src/makemove.cpp

@@ -15,6 +15,7 @@ template void ClearPiece<true>(const int piece, const int to, Position* pos);
 // Remove a piece from a square, the UPDATE params determines whether we want to update the NNUE weights or not
 template <bool UPDATE = true>
 void ClearPiece(const int piece, const int from, Position* pos) {
+    assert(piece != EMPTY);
     // Do this first because if we happened to have moved the king we first need to get1lsb the king bitboard before removing it
     if constexpr(UPDATE){
         std::array<bool, 2> flip({get_file[KingSQ(pos, WHITE)] > 3, get_file[KingSQ(pos, BLACK)] > 3});
@@ -27,6 +28,10 @@ void ClearPiece(const int piece, const int from, Position* pos) {
     HashKey(pos->posKey, PieceKeys[piece][from]);
     if(GetPieceType(piece) == PAWN)
         HashKey(pos->pawnKey, PieceKeys[piece][from]);
+    else if(Color[piece] == WHITE)
+        HashKey(pos->whiteNonPawnKey, PieceKeys[piece][from]);
+    else
+        HashKey(pos->blackNonPawnKey, PieceKeys[piece][from]);
 }
 
 template void AddPiece<false>(const int piece, const int to, Position* pos);
@@ -35,13 +40,18 @@ template void AddPiece<true>(const int piece, const int to, Position* pos);
 // Add a piece to a square, the UPDATE params determines whether we want to update the NNUE weights or not
 template <bool UPDATE = true>
 void AddPiece(const int piece, const int to, Position* pos) {
+    assert(piece != EMPTY);
     const int color = Color[piece];
     set_bit(pos->bitboards[piece], to);
     set_bit(pos->occupancies[color], to);
     pos->pieces[to] = piece;
     HashKey(pos->posKey, PieceKeys[piece][to]);
     if(GetPieceType(piece) == PAWN)
         HashKey(pos->pawnKey, PieceKeys[piece][to]);
+    else if(Color[piece] == WHITE)
+        HashKey(pos->whiteNonPawnKey, PieceKeys[piece][to]);
+    else
+        HashKey(pos->blackNonPawnKey, PieceKeys[piece][to]);
     // Do this last because if we happened to have moved the king we first need to re-add to the piece bitboards least we get1lsb an empty bitboard
     if constexpr(UPDATE){
         std::array<bool, 2> flip({get_file[KingSQ(pos, WHITE)] > 3, get_file[KingSQ(pos, BLACK)] > 3});

src/position.cpp

@@ -81,6 +81,19 @@ ZobristKey GeneratePawnKey(const Position* pos) {
     return pawnKey;
 }
 
+// Generates zobrist key (for non-pawns) from scratch
+ZobristKey GenerateNonPawnKey(const Position* pos, int side) {
+    Bitboard nonPawnKey = 0;
+    for (int sq = 0; sq < 64; ++sq) {
+        // get piece on that square
+        const int piece = pos->PieceOn(sq);
+        if (piece != EMPTY && piece != WP && piece != BP && Color[piece] == side) {
+            nonPawnKey ^= PieceKeys[piece][sq];
+        }
+    }
+    return nonPawnKey;
+}
+
 // parse FEN string
 void ParseFen(const std::string& command, Position* pos) {
 
@@ -208,6 +221,8 @@ void ParseFen(const std::string& command, Position* pos) {
 
     pos->posKey = GeneratePosKey(pos);
     pos->pawnKey = GeneratePawnKey(pos);
+    pos->whiteNonPawnKey = GenerateNonPawnKey(pos, WHITE);
+    pos->blackNonPawnKey = GenerateNonPawnKey(pos, BLACK);
 
     // Update pinmasks and checkers
     UpdatePinsAndCheckers(pos, pos->side);

src/position.h

@@ -45,6 +45,8 @@ struct Position {
     // unique  hashkey  that encodes a board position
     ZobristKey posKey = 0ULL;
     ZobristKey pawnKey = 0ULL;
+    ZobristKey whiteNonPawnKey = 0ULL;
+    ZobristKey blackNonPawnKey = 0ULL;
     // stores the state of the board  rollback purposes
     int historyStackHead = 0;
     BoardState    history[MAXPLY];

src/search.h

@@ -22,7 +22,9 @@ struct SearchData {
     int captHist[12 * 64][6] = {};
     int counterMoves[64 * 64] = {};
     int contHist[12 * 64][12 * 64] = {};
-    int corrHist[2][CORRHIST_SIZE] = {};
+    int pawnCorrHist[2][CORRHIST_SIZE] = {};
+    int whiteNonPawnCorrHist[2][CORRHIST_SIZE] = {};
+    int blackNonPawnCorrHist[2][CORRHIST_SIZE] = {};
 };
 
 struct PvTable {

src/types.h

@@ -4,7 +4,7 @@
 // include the tune stuff here to give it global visibility
 #include "tune.h"
 
-#define NAME "Alexandria-7.0.22"
+#define NAME "Alexandria-7.0.23"
 
 inline int reductions[2][64][64];
 inline int lmp_margin[64][2];