static int evaluate() { int sq; int score[2]; sq_t king_square[2]; state_t *state = &board->state; //clearing data: score[W] = 0; score[B] = 0; ///pawn evaluation: eval_pawn_struct(&score[0]); ///piece evaluation //kings king_square[W] = King_Square(W); king_square[B] = King_Square(B); score[W] += psq_table[WK][king_square[W]]; score[W] += eval_white_king(king_square[W]); score[B] += psq_table[BK][king_square[B]]; score[B] += eval_black_king(king_square[B]); //queens: for(sq = PLS(WQ); sq <= H8; sq = PLN(sq)) { score[W] += psq_table[WQ][sq]; if(calc_rank(sq) == RANK_7 && calc_rank(king_square[BLACK]) == RANK_8) score[W] += QUEEN_ON_7TH_REWARD; score[W] += eval_q_mobility(sq,W); } for(sq = PLS(BQ); sq <= H8; sq = PLN(sq)) { score[B] += psq_table[BQ][sq]; if(calc_rank(sq) == RANK_2 && calc_rank(king_square[WHITE]) == RANK_1) score[B] += QUEEN_ON_7TH_REWARD; score[B] += eval_q_mobility(sq,B); } //rooks: for(sq = PLS(WR); sq <= H8; sq = PLN(sq)) { score[W] += psq_table[WR][sq]; score[W] += eval_white_rook(sq); score[W] += eval_r_mobility(sq,W); } for(sq = PLS(BR); sq <= H8; sq = PLN(sq)) { score[B] += psq_table[BR][sq]; score[B] += eval_black_rook(sq); score[B] += eval_r_mobility(sq,B); } //bishops: for(sq = PLS(WB); sq <= H8; sq = PLN(sq)) { score[W] += psq_table[WB][sq]; score[W] += eval_white_bishop(sq); score[W] += eval_b_mobility(sq,W); //outposts - twice as low than a knight outpost: if(!((1ULL << rsz[sq]) & pawn_attacks[B])) { if(psq_outposts[W][sq]) { //if not attacked by an opponent's pawn, //this could be a weak square that matters, //in accordance with the outposts table: score[W] += (psq_outposts[W][sq]) / 2; //additional bonus if it's reinforced by own pawns: if((1ULL << rsz[sq]) & pawn_attacks[W]) score[W] += (psq_outposts[W][sq]) / 2; } } } for(sq = PLS(BB); sq <= H8; sq = PLN(sq)) { score[B] += psq_table[BB][sq]; score[B] += eval_black_bishop(sq); score[B] += eval_b_mobility(sq,B); //outposts: if(!((1ULL << rsz[sq]) & pawn_attacks[W])) { if(psq_outposts[B][sq]) { score[B] += (psq_outposts[B][sq]) / 2; if((1ULL << rsz[sq]) & pawn_attacks[B]) score[B] += (psq_outposts[B][sq]) / 2; } } } //knights: for(sq = PLS(WN); sq <= H8; sq = PLN(sq)) { score[W] += psq_table[WN][sq]; score[W] += eval_n_mobility(sq,W); //outposts: if(!((1ULL << rsz[sq]) & pawn_attacks[B])) { if(psq_outposts[W][sq]) { score[W] += psq_outposts[W][sq]; if((1ULL << rsz[sq]) & pawn_attacks[W]) score[W] += psq_outposts[W][sq]; } } } for(sq = PLS(BN); sq <= H8; sq = PLN(sq)) { score[B] += psq_table[BN][sq]; score[B] += eval_n_mobility(sq,B); //outposts: if(!((1ULL << rsz[sq]) & pawn_attacks[W])) { if(psq_outposts[B][sq]) { score[B] += psq_outposts[B][sq]; if((1ULL << rsz[sq]) & pawn_attacks[B]) score[B] += psq_outposts[B][sq]; } } } //bishop pair bonus depending on pawns on board: if(Bishops(W) >= 2) score[W] += BISHOP_PAIR_REWARD - state->pawns; if(Bishops(B) >= 2) score[B] += BISHOP_PAIR_REWARD - state->pawns; //calculate basic knight and rook material imbalances: /********************************************************** quote from GM L.Kaufman: "A further refinement would be to raise the knight's value by 1/16 and lower the rook's value by 1/8 for each pawn above five of the side being valued, with the opposite adjustment for each pawn short of five". ***********************************************************/ score[W] += Rooks(W) * rook_imbalance[Pawns(W)]; score[W] += Knights(W) * knight_imbalance[Pawns(W)]; score[B] += Rooks(B) * rook_imbalance[Pawns(B)]; score[B] += Knights(B) * knight_imbalance[Pawns(B)]; if(opening) { score[W] += eval_white_opening(); score[B] += eval_black_opening(); } ///final results: score[W] += state->material_value[WHITE] + \ state->pawn_value[WHITE]; score[B] += state->material_value[BLACK] + \ state->pawn_value[BLACK]; if(board->side == W) return (score[W]-score[B]); else return -(score[W]-score[B]); }
static int evaluate_endgame() { int sq; int score[2]; sq_t king_square[2]; state_t *state = &board->state; //clearing data: score[W] = 0; score[B] = 0; ///pawn evaluation: eval_pawn_struct_endgame(&score[0]); ///piece evaluation //kings king_square[W] = King_Square(W); king_square[B] = King_Square(B); score[W] += endgame_king_psq[W][king_square[W]]; score[B] += endgame_king_psq[B][king_square[B]]; if(state->material) { //queens: for(sq = PLS(WQ); sq <= H8; sq = PLN(sq)) { score[W] += psq_table[WQ][sq]; if(calc_rank(sq) == RANK_7 && calc_rank(king_square[BLACK]) == RANK_8) score[W] += QUEEN_ON_7TH_REWARD; } for(sq = PLS(BQ); sq <= H8; sq = PLN(sq)) { score[B] += psq_table[BQ][sq]; if(calc_rank(sq) == RANK_2 && calc_rank(king_square[WHITE]) == RANK_1) score[B] += QUEEN_ON_7TH_REWARD; } //rooks: for(sq = PLS(WR); sq <= H8; sq = PLN(sq)) { score[W] += psq_table[WR][sq]; score[W] += eval_white_rook(sq); } for(sq = PLS(BR); sq <= H8; sq = PLN(sq)) { score[B] += psq_table[BR][sq]; score[B] += eval_black_rook(sq); } //bishops: for(sq = PLS(WB); sq <= H8; sq = PLN(sq)) { score[W] += psq_table[WB][sq]; score[W] += eval_white_bishop(sq); //outposts if(!((1ULL << rsz[sq]) & pawn_attacks[B])) { if(psq_outposts[W][sq]) { score[W] += (psq_outposts[W][sq]) / 2; if((1ULL << rsz[sq]) & pawn_attacks[W]) score[W] += (psq_outposts[W][sq]) / 2; } } } for(sq = PLS(BB); sq <= H8; sq = PLN(sq)) { score[B] += psq_table[BB][sq]; score[B] += eval_black_bishop(sq); //outposts: if(!((1ULL << rsz[sq]) & pawn_attacks[W])) { if(psq_outposts[B][sq]) { score[B] += (psq_outposts[B][sq]) / 2; if((1ULL << rsz[sq]) & pawn_attacks[B]) score[B] += (psq_outposts[B][sq]) / 2; } } } //knights: for(sq = PLS(WN); sq <= H8; sq = PLN(sq)) { score[W] += psq_table[WN][sq]; //outposts: if(!((1ULL << rsz[sq]) & pawn_attacks[B])) { if(psq_outposts[W][sq]) { score[W] += psq_outposts[W][sq]; if((1ULL << rsz[sq]) & pawn_attacks[W]) score[W] += psq_outposts[W][sq]; } } } for(sq = PLS(BN); sq <= H8; sq = PLN(sq)) { score[B] += psq_table[BN][sq]; //outposts: if(!((1ULL << rsz[sq]) & pawn_attacks[W])) { if(psq_outposts[B][sq]) { score[B] += psq_outposts[B][sq]; if((1ULL << rsz[sq]) & pawn_attacks[B]) score[B] += psq_outposts[B][sq]; } } } //bishop pair bonus depending on pawns on board: if(Bishops(W) >= 2) score[W] += BISHOP_PAIR_REWARD - state->pawns; if(Bishops(B) >= 2) score[B] += BISHOP_PAIR_REWARD - state->pawns; //calculate basic knight and rook material imbalances: score[W] += Rooks(W) * rook_imbalance[Pawns(W)]; score[W] += Knights(W) * knight_imbalance[Pawns(W)]; score[B] += Rooks(B) * rook_imbalance[Pawns(B)]; score[B] += Knights(B) * knight_imbalance[Pawns(B)]; //a piece of code to encourage exchanges //in case of material advantage: if(state->material_value[W] > state->material_value[B] || state->pawn_value[W] > state->pawn_value[B]) score[W] -= (state->piece_count[W] + state->piece_count[B]) * 2; if(state->material_value[B] > state->material_value[W] || state->pawn_value[B] > state->pawn_value[W]) score[B] -= (state->piece_count[B] + state->piece_count[W]) * 2; } return endeval(&score[0]); }
* The algorithm is quite simple. Using the attack bitmaps, we enumerate all* * the pieces that are attacking [target] for either side. Then we simply * * use the lowest piece (value) for the correct side to capture on [target]. * * we continually "flip" sides taking the lowest piece each time. * * * * As a piece is used, if it is a sliding piece (pawn, bishop, rook or queen)* * we remove the piece, then generate moves of bishop/queen or rook/queen * * and then add those in to the attackers, removing any attacks that have * * already been used. * * * ******************************************************************************* */ int Swap(TREE * RESTRICT tree, int move, int wtm) { uint64_t attacks, temp = 0, toccupied = OccupiedSquares; uint64_t bsliders = Bishops(white) | Bishops(black) | Queens(white) | Queens(black); uint64_t rsliders = Rooks(white) | Rooks(black) | Queens(white) | Queens(black); int attacked_piece, piece, nc = 1, swap_list[32]; int source = From(move); int target = To(move); /* ************************************************************ * * * Determine which squares attack <target> for each side. * * initialize by placing the piece on <target> first in * * the list as it is being captured to start things off. * * * ************************************************************ */