- assert(!pos.checkers());
-
- EvalInfo ei;
- Value margins[COLOR_NB];
- Score score, mobilityWhite, mobilityBlack;
- Thread* th = pos.this_thread();
-
- // 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 = Material::probe(pos, th->materialTable, th->endgames);
- 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 = Pawns::probe(pos, th->pawnsTable);
- score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
-
- // 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, Trace>(pos, ei)
- - evaluate_threats<BLACK, Trace>(pos, ei);
-
- // Evaluate passed pawns, we need full attack information including king
- score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
- - evaluate_passed_pawns<BLACK, Trace>(pos, ei);
-
- // If one side has only a king, score for potential unstoppable pawns
- if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
- score += evaluate_unstoppable_pawns(pos, WHITE, ei)
- - evaluate_unstoppable_pawns(pos, BLACK, 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(s * ei.mi->space_weight(), 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);