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. *
* *
************************************************************
*/
