}
}
-/// evaluate() is the evaluator for the outer world. It returns a static
-/// evaluation of the position from the point of view of the side to move.
-Value Eval::evaluate(const Position& pos) {
-
- assert(!pos.checkers());
-
- Value v;
+/// simple_eval() returns a static, purely materialistic evaluation of the position
+/// from the point of view of the given color. It can be divided by PawnValue to get
+/// an approximation of the material advantage on the board in terms of pawns.
- int nnueComplexity;
- int npm = pos.non_pawn_material() / 64;
+Value Eval::simple_eval(const Position& pos, Color c) {
+ return PawnValue * (pos.count<PAWN>(c) - pos.count<PAWN>(~c))
+ + (pos.non_pawn_material(c) - pos.non_pawn_material(~c));
+}
- Color stm = pos.side_to_move();
- Value optimism = pos.this_thread()->optimism[stm];
- Value nnue = NNUE::evaluate(pos, true, &nnueComplexity);
+/// evaluate() is the evaluator for the outer world. It returns a static evaluation
+/// of the position from the point of view of the side to move.
- int material = pos.non_pawn_material(stm) - pos.non_pawn_material(~stm)
- + 126 * (pos.count<PAWN>(stm) - pos.count<PAWN>(~stm));
+Value Eval::evaluate(const Position& pos) {
- // Blend optimism and eval with nnue complexity and material imbalance
- optimism += optimism * (nnueComplexity + abs(material - nnue)) / 512;
- nnue -= nnue * (nnueComplexity + abs(material - nnue)) / 32768;
+ assert(!pos.checkers());
- v = ( nnue * (915 + npm + 9 * pos.count<PAWN>())
- + optimism * (154 + npm + pos.count<PAWN>())) / 1024;
+ Value v;
+ Color stm = pos.side_to_move();
+ int shuffling = pos.rule50_count();
+ int simpleEval = simple_eval(pos, stm) + (int(pos.key() & 7) - 3);
+
+ bool lazy = abs(simpleEval) >= RookValue + KnightValue
+ + 16 * shuffling * shuffling
+ + abs(pos.this_thread()->bestValue)
+ + abs(pos.this_thread()->rootSimpleEval);
+
+ if (lazy)
+ v = Value(simpleEval);
+ else
+ {
+ int nnueComplexity;
+ Value nnue = NNUE::evaluate(pos, true, &nnueComplexity);
+
+ Value optimism = pos.this_thread()->optimism[stm];
+
+ // Blend optimism and eval with nnue complexity and material imbalance
+ optimism += optimism * (nnueComplexity + abs(simpleEval - nnue)) / 512;
+ nnue -= nnue * (nnueComplexity + abs(simpleEval - nnue)) / 32768;
+
+ int npm = pos.non_pawn_material() / 64;
+ v = ( nnue * (915 + npm + 9 * pos.count<PAWN>())
+ + optimism * (154 + npm + pos.count<PAWN>())) / 1024;
+ }
// Damp down the evaluation linearly when shuffling
- v = v * (200 - pos.rule50_count()) / 214;
+ v = v * (200 - shuffling) / 214;
// Guarantee evaluation does not hit the tablebase range
v = std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
// Reset any global variable used in eval
pos.this_thread()->bestValue = VALUE_ZERO;
+ pos.this_thread()->rootSimpleEval = VALUE_ZERO;
pos.this_thread()->optimism[WHITE] = VALUE_ZERO;
pos.this_thread()->optimism[BLACK] = VALUE_ZERO;