Change evaluate() signature

Hide EvalInfo and return just the score and the margin.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/evaluate.cpp

@@ -38,6 +38,54 @@
 
 namespace {
 
+  // Struct EvalInfo contains various information computed and collected
+  // by the evaluation functions.
+  struct EvalInfo {
+
+    // Middle and end game position's static evaluations
+    Score value;
+
+    // margin[color] stores the evaluation margins we should consider for
+    // the given position. This is a kind of uncertainty estimation and
+    // typically is used by the search for pruning decisions.
+    Value margin[2];
+
+    // Pointers to material and pawn hash table entries
+    MaterialInfo* mi;
+    PawnInfo* pi;
+
+    // attackedBy[color][piece type] is a bitboard representing all squares
+    // attacked by a given color and piece type, attackedBy[color][0] contains
+    // all squares attacked by the given color.
+    Bitboard attackedBy[2][8];
+
+    // kingZone[color] is the zone around the enemy king which is considered
+    // by the king safety evaluation. This consists of the squares directly
+    // adjacent to the king, and the three (or two, for a king on an edge file)
+    // squares two ranks in front of the king. For instance, if black's king
+    // is on g8, kingZone[WHITE] is a bitboard containing the squares f8, h8,
+    // f7, g7, h7, f6, g6 and h6.
+    Bitboard kingZone[2];
+
+    // kingAttackersCount[color] is the number of pieces of the given color
+    // which attack a square in the kingZone of the enemy king.
+    int kingAttackersCount[2];
+
+    // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
+    // given color which attack a square in the kingZone of the enemy king. The
+    // weights of the individual piece types are given by the variables
+    // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
+    // KnightAttackWeight in evaluate.cpp
+    int kingAttackersWeight[2];
+
+    // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
+    // directly adjacent to the king of the given color. Pieces which attack
+    // more than one square are counted multiple times. For instance, if black's
+    // king is on g8 and there's a white knight on g5, this knight adds
+    // 2 to kingAdjacentZoneAttacksCount[BLACK].
+    int kingAdjacentZoneAttacksCount[2];
+  };
+
   const int Sign[2] = { 1, -1 };
 
   // Evaluation grain size, must be a power of 2
@@ -187,7 +235,7 @@ namespace {
 
   // Function prototypes
   template<bool HasPopCnt>
-  Value do_evaluate(const Position& pos, EvalInfo& ei);
+  Value do_evaluate(const Position& pos, Value margins[]);
 
   template<Color Us, bool HasPopCnt>
   void init_attack_tables(const Position& pos, EvalInfo& ei);
@@ -229,17 +277,18 @@ void prefetchPawn(Key key, int threadID) {
 /// evaluate() is the main evaluation function. It always computes two
 /// values, an endgame score and a middle game score, and interpolates
 /// between them based on the remaining material.
-Value evaluate(const Position& pos, EvalInfo& ei) {
+Value evaluate(const Position& pos, Value margins[]) {
 
-    return CpuHasPOPCNT ? do_evaluate<true>(pos, ei)
+    return CpuHasPOPCNT ? do_evaluate<true>(pos, margins)
-                        : do_evaluate<false>(pos, ei);
+                        : do_evaluate<false>(pos, margins);
 }
 
 namespace {
 
 template<bool HasPopCnt>
-Value do_evaluate(const Position& pos, EvalInfo& ei) {
+Value do_evaluate(const Position& pos, Value margins[]) {
 
+  EvalInfo ei;
   ScaleFactor factor[2];
   Score mobility;
 
@@ -344,6 +393,10 @@ Value do_evaluate(const Position& pos, EvalInfo& ei) {
           factor[BLACK] = sf;
   }
 
+  // Populate margins[]
+  margins[WHITE] = ei.margin[WHITE];
+  margins[BLACK] = ei.margin[BLACK];
+
   // Interpolate between the middle game and the endgame score
   return Sign[pos.side_to_move()] * scale_by_game_phase(ei.value, phase, factor);
 }

src/evaluate.h

@@ -21,85 +21,14 @@
 #if !defined(EVALUATE_H_INCLUDED)
 #define EVALUATE_H_INCLUDED
 
-////
+#include "color.h"
-//// Includes
+#include "value.h"
-////
 
-#include <iostream>
-
-#include "material.h"
-#include "pawns.h"
-
-
-////
-//// Types
-////
-
-
-/// The EvalInfo struct contains various information computed and collected
-/// by the evaluation function. An EvalInfo object is passed as one of the
-/// arguments to the evaluation function, and the search can make use of its
-/// contents to make intelligent search decisions.
-///
-/// At the moment, this is not utilized very much: The only part of the
-/// EvalInfo object which is used by the search is margin.
 class Position;
 
-struct EvalInfo {
+extern Value evaluate(const Position& pos, Value margins[]);
-
-  // Middle and end game position's static evaluations
-  Score value;
-
-  // margin[color] stores the evaluation margins we should consider for
-  // the given position. This is a kind of uncertainty estimation and
-  // typically is used by the search for pruning decisions.
-  Value margin[2];
-
-  // Pointers to material and pawn hash table entries
-  MaterialInfo* mi;
-  PawnInfo* pi;
-
-  // attackedBy[color][piece type] is a bitboard representing all squares
-  // attacked by a given color and piece type, attackedBy[color][0] contains
-  // all squares attacked by the given color.
-  Bitboard attackedBy[2][8];
-
-  // kingZone[color] is the zone around the enemy king which is considered
-  // by the king safety evaluation. This consists of the squares directly
-  // adjacent to the king, and the three (or two, for a king on an edge file)
-  // squares two ranks in front of the king. For instance, if black's king
-  // is on g8, kingZone[WHITE] is a bitboard containing the squares f8, h8,
-  // f7, g7, h7, f6, g6 and h6.
-  Bitboard kingZone[2];
-
-  // kingAttackersCount[color] is the number of pieces of the given color
-  // which attack a square in the kingZone of the enemy king.
-  int kingAttackersCount[2];
-
-  // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
-  // given color which attack a square in the kingZone of the enemy king. The
-  // weights of the individual piece types are given by the variables
-  // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
-  // KnightAttackWeight in evaluate.cpp
-  int kingAttackersWeight[2];
-
-  // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
-  // directly adjacent to the king of the given color. Pieces which attack
-  // more than one square are counted multiple times. For instance, if black's
-  // king is on g8 and there's a white knight on g5, this knight adds
-  // 2 to kingAdjacentZoneAttacksCount[BLACK].
-  int kingAdjacentZoneAttacksCount[2];
-};
-
-
-////
-//// Prototypes
-////
-
-extern Value evaluate(const Position& pos, EvalInfo& ei);
 extern void init_eval(int threads);
 extern void quit_eval();
 extern void read_weights(Color sideToMove);
 
-
 #endif // !defined(EVALUATE_H_INCLUDED)

src/search.cpp

@@ -714,7 +714,7 @@ namespace {
 
   Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
 
-    EvalInfo ei;
+    Value margins[2];
     StateInfo st;
     CheckInfo ci(pos);
     int64_t nodes;
@@ -739,7 +739,7 @@ namespace {
 
     // Step 5. Evaluate the position statically
     // At root we do this only to get reference value for child nodes
-    ss->eval = isCheck ? VALUE_NONE : evaluate(pos, ei);
+    ss->eval = isCheck ? VALUE_NONE : evaluate(pos, margins);
 
     // Step 6. Razoring (omitted at root)
     // Step 7. Static null move pruning (omitted at root)
@@ -975,7 +975,7 @@ namespace {
     assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
 
     Move movesSearched[256];
-    EvalInfo ei;
+    Value margins[2];
     StateInfo st;
     const TTEntry *tte;
     Key posKey;
@@ -1051,13 +1051,13 @@ namespace {
         assert(tte->static_value() != VALUE_NONE);
 
         ss->eval = tte->static_value();
-        ei.margin[pos.side_to_move()] = tte->static_value_margin();
+        margins[pos.side_to_move()] = tte->static_value_margin();
         refinedValue = refine_eval(tte, ss->eval, ply);
     }
     else
     {
-        refinedValue = ss->eval = evaluate(pos, ei);
+        refinedValue = ss->eval = evaluate(pos, margins);
-        TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ei.margin[pos.side_to_move()]);
+        TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, margins[pos.side_to_move()]);
     }
 
     // Save gain for the parent non-capture move
@@ -1371,7 +1371,7 @@ namespace {
 
     ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
     move = (bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove);
-    TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ei.margin[pos.side_to_move()]);
+    TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, margins[pos.side_to_move()]);
 
     // Update killers and history only for non capture moves that fails high
     if (    bestValue >= beta
@@ -1401,7 +1401,7 @@ namespace {
     assert(ply > 0 && ply < PLY_MAX);
     assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
 
-    EvalInfo ei;
+    Value margins[2];
     StateInfo st;
     Move ttMove, move;
     Value bestValue, value, futilityValue, futilityBase;
@@ -1442,11 +1442,11 @@ namespace {
         {
             assert(tte->static_value() != VALUE_NONE);
 
-            ei.margin[pos.side_to_move()] = tte->static_value_margin();
+            margins[pos.side_to_move()] = tte->static_value_margin();
             bestValue = tte->static_value();
         }
         else
-            bestValue = evaluate(pos, ei);
+            bestValue = evaluate(pos, margins);
 
         ss->eval = bestValue;
         update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
@@ -1455,7 +1455,7 @@ namespace {
         if (bestValue >= beta)
         {
             if (!tte)
-                TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, ei.margin[pos.side_to_move()]);
+                TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, margins[pos.side_to_move()]);
 
             return bestValue;
         }
@@ -1467,7 +1467,7 @@ namespace {
         deepChecks = (depth == -ONE_PLY && bestValue >= beta - PawnValueMidgame / 8);
 
         // Futility pruning parameters, not needed when in check
-        futilityBase = bestValue + FutilityMarginQS + ei.margin[pos.side_to_move()];
+        futilityBase = bestValue + FutilityMarginQS + margins[pos.side_to_move()];
         enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
     }
 
@@ -1552,7 +1552,7 @@ namespace {
     // Update transposition table
     Depth d = (depth == DEPTH_ZERO ? DEPTH_ZERO : DEPTH_ZERO - ONE_PLY);
     ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
-    TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, d, ss->bestMove, ss->eval, ei.margin[pos.side_to_move()]);
+    TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, d, ss->bestMove, ss->eval, margins[pos.side_to_move()]);
 
     // Update killers only for checking moves that fails high
     if (    bestValue >= beta
@@ -2242,7 +2242,7 @@ namespace {
     StateInfo st;
     TTEntry* tte;
     Position p(pos, pos.thread());
-    EvalInfo ei;
+    Value margins[2];
     Value v;
 
     for (int i = 0; pv[i] != MOVE_NONE; i++)
@@ -2250,8 +2250,8 @@ namespace {
         tte = TT.retrieve(p.get_key());
         if (!tte || tte->move() != pv[i])
         {
-            v = (p.is_check() ? VALUE_NONE : evaluate(p, ei));
+            v = (p.is_check() ? VALUE_NONE : evaluate(p, margins));
-            TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, ei.margin[pos.side_to_move()]);
+            TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, margins[pos.side_to_move()]);
         }
         p.do_move(pv[i], st);
     }

src/uci.cpp

@@ -150,10 +150,10 @@ namespace {
     }
     else if (token == "eval")
     {
-        EvalInfo ei;
+        Value margins[2];
         cout << "Incremental mg: "   << mg_value(RootPosition.value())
              << "\nIncremental eg: " << eg_value(RootPosition.value())
-             << "\nFull eval: "      << evaluate(RootPosition, ei) << endl;
+             << "\nFull eval: "      << evaluate(RootPosition, margins) << endl;
     }
     else if (token == "key")
         cout << "key: " << hex << RootPosition.get_key()

src/value.h

@@ -21,13 +21,6 @@
 #if !defined(VALUE_H_INCLUDED)
 #define VALUE_H_INCLUDED
 
-////
-//// Includes
-////
-
-#include "piece.h"
-
-
 ////
 //// Types
 ////