- /// init() computes evaluation weights from the corresponding UCI parameters
- /// and setup king tables.
-
- void init() {
-
- Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
- Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
- Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
- Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
- Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
-
- // King safety is asymmetrical. Our king danger level is weighted by
- // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
- // If running in analysis mode, make sure we use symmetrical king safety. We
- // do this by replacing both Weights[kingDangerUs] and Weights[kingDangerThem]
- // by their average.
- if (Options["UCI_AnalyseMode"])
- Weights[KingDangerUs] = Weights[KingDangerThem] = (Weights[KingDangerUs] + Weights[KingDangerThem]) / 2;
-
- const int MaxSlope = 30;
- const int Peak = 1280;
-
- for (int t = 0, i = 1; i < 100; i++)
- {
- t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
-
- KingDangerTable[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
- KingDangerTable[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
- }
- }
-
-
- /// trace() is like evaluate() but instead of a value returns a string suitable
- /// to be print on stdout with the detailed descriptions and values of each
- /// evaluation term. Used mainly for debugging.
-
- std::string trace(const Position& pos) {
-
- Value margin;
- std::string totals;
-
- RootColor = pos.side_to_move();
-
- TraceStream.str("");
- TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
- memset(TracedScores, 0, 2 * 16 * sizeof(Score));
-
- do_evaluate<true>(pos, margin);
-
- totals = TraceStream.str();
- TraceStream.str("");
-
- TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
- << " | MG EG | MG EG | MG EG \n"
- << "---------------------+-------------+-------------+---------------\n";
-
- trace_row("Material, PST, Tempo", PST);
- trace_row("Material imbalance", IMBALANCE);
- trace_row("Pawns", PAWN);
- trace_row("Knights", KNIGHT);
- trace_row("Bishops", BISHOP);
- trace_row("Rooks", ROOK);
- trace_row("Queens", QUEEN);
- trace_row("Mobility", MOBILITY);
- trace_row("King safety", KING);
- trace_row("Threats", THREAT);
- trace_row("Passed pawns", PASSED);
- trace_row("Unstoppable pawns", UNSTOPPABLE);
- trace_row("Space", SPACE);
-
- TraceStream << "---------------------+-------------+-------------+---------------\n";
- trace_row("Total", TOTAL);
- TraceStream << totals;
-
- return TraceStream.str();
- }
-
-} // namespace Eval
-
-
-namespace {
-
-template<bool Trace>
-Value do_evaluate(const Position& pos, Value& margin) {
-
- assert(!pos.in_check());
-
- EvalInfo ei;
- Value margins[2];
- Score score, mobilityWhite, mobilityBlack;
-
- // margins[] store the uncertainty estimation of position's evaluation
- // that typically is used by the search for pruning decisions.
- margins[WHITE] = margins[BLACK] = VALUE_ZERO;
-
- // Initialize score by reading the incrementally updated scores included
- // in the position object (material + piece square tables) and adding
- // Tempo bonus. Score is computed from the point of view of white.
- score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
-
- // Probe the material hash table
- ei.mi = pos.this_thread()->materialTable.probe(pos);
- score += ei.mi->material_value();
-
- // If we have a specialized evaluation function for the current material
- // configuration, call it and return.
- if (ei.mi->specialized_eval_exists())
- {
- margin = VALUE_ZERO;
- return ei.mi->evaluate(pos);
- }
-
- // Probe the pawn hash table
- ei.pi = pos.this_thread()->pawnTable.probe(pos);
- score += ei.pi->pawns_value();
-
- // Initialize attack and king safety bitboards
- init_eval_info<WHITE>(pos, ei);
- init_eval_info<BLACK>(pos, ei);
-
- // Evaluate pieces and mobility
- score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
- - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
-
- score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
-
- // Evaluate kings after all other pieces because we need complete attack
- // information when computing the king safety evaluation.
- score += evaluate_king<WHITE, Trace>(pos, ei, margins)
- - evaluate_king<BLACK, Trace>(pos, ei, margins);
-
- // Evaluate tactical threats, we need full attack information including king
- score += evaluate_threats<WHITE>(pos, ei)
- - evaluate_threats<BLACK>(pos, ei);
-
- // Evaluate passed pawns, we need full attack information including king
- score += evaluate_passed_pawns<WHITE>(pos, ei)
- - evaluate_passed_pawns<BLACK>(pos, ei);
-
- // If one side has only a king, check whether exists any unstoppable passed pawn
- if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
- score += evaluate_unstoppable_pawns(pos, ei);
-
- // Evaluate space for both sides, only in middle-game.
- if (ei.mi->space_weight())
- {
- int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
- score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
- }
-
- // Scale winning side if position is more drawish that what it appears
- ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
- : ei.mi->scale_factor(pos, BLACK);
-
- // If we don't already have an unusual scale factor, check for opposite
- // colored bishop endgames, and use a lower scale for those.
- if ( ei.mi->game_phase() < PHASE_MIDGAME
- && pos.opposite_bishops()
- && sf == SCALE_FACTOR_NORMAL)
- {
- // Only the two bishops ?
- if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
- && pos.non_pawn_material(BLACK) == BishopValueMidgame)
- {
- // Check for KBP vs KB with only a single pawn that is almost
- // certainly a draw or at least two pawns.
- bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
- sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
- }
- else
- // Endgame with opposite-colored bishops, but also other pieces. Still
- // a bit drawish, but not as drawish as with only the two bishops.
- sf = ScaleFactor(50);
- }