Use self-describing constants instead of numbers

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 856c003a3654f758f44cc5523264fb84910255d7..d07db40f4d749d852d061f77dab6ed6fdae4757b 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -42,6 +42,7 @@ namespace Search {
   LimitsType Limits;
   std::vector<RootMove> RootMoves;
   Position RootPosition;
+  Color RootColor;
   Time::point SearchTime;
   StateStackPtr SetupStates;
 }
@@ -91,7 +92,7 @@ namespace {
   int BestMoveChanges;
   int SkillLevel;
   bool SkillLevelEnabled, Chess960;
-  Value DrawValue[2];
+  Value DrawValue[COLOR_NB];
   History H;
 
   template <NodeType NT>
@@ -136,7 +137,7 @@ void Search::init() {
 
   // Init futility move count array
   for (d = 0; d < 32; d++)
-      FutilityMoveCounts[d] = int(3.001 + 0.25 * pow(d, 2.0));
+      FutilityMoveCounts[d] = int(3.001 + 0.25 * pow(double(d), 2.0));
 }
 
 
@@ -174,7 +175,7 @@ void Search::think() {
 
   Position& pos = RootPosition;
   Chess960 = pos.is_chess960();
-  Eval::RootColor = pos.side_to_move();
+  RootColor = pos.side_to_move();
   TimeMgr.init(Limits, pos.startpos_ply_counter(), pos.side_to_move());
   TT.new_search();
   H.clear();
@@ -192,8 +193,8 @@ void Search::think() {
   {
       int cf = Options["Contempt Factor"] * PawnValueMg / 100;  // In centipawns
       cf = cf * MaterialTable::game_phase(pos) / PHASE_MIDGAME; // Scale down with phase
-      DrawValue[ Eval::RootColor] = VALUE_DRAW - Value(cf);
-      DrawValue[~Eval::RootColor] = VALUE_DRAW + Value(cf);
+      DrawValue[ RootColor] = VALUE_DRAW - Value(cf);
+      DrawValue[~RootColor] = VALUE_DRAW + Value(cf);
   }
   else
       DrawValue[WHITE] = DrawValue[BLACK] = VALUE_DRAW;
@@ -557,6 +558,8 @@ namespace {
             : ttValue >= beta ? (tte->type() & BOUND_LOWER)
                               : (tte->type() & BOUND_UPPER)))
     {
+        assert(ttValue != VALUE_NONE); // Due to depth > DEPTH_NONE
+
         TT.refresh(tte);
         ss->currentMove = ttMove; // Can be MOVE_NONE
 
@@ -574,6 +577,7 @@ namespace {
     // Step 5. Evaluate the position statically and update parent's gain statistics
     if (inCheck)
         ss->eval = ss->evalMargin = refinedValue = VALUE_NONE;
+
     else if (tte)
     {
         assert(tte->static_value() != VALUE_NONE);
@@ -818,6 +822,8 @@ split_point_start: // At split points actual search starts from here
           &&  pos.pl_move_is_legal(move, ci.pinned)
           &&  abs(ttValue) < VALUE_KNOWN_WIN)
       {
+          assert(ttValue != VALUE_NONE);
+
           Value rBeta = ttValue - int(depth);
           ss->excludedMove = move;
           ss->skipNullMove = true;
@@ -1018,7 +1024,8 @@ split_point_start: // At split points actual search starts from here
     // If we are in a singular extension search then return a fail low score.
     // A split node has at least one move, the one tried before to be splitted.
     if (!moveCount)
-        return excludedMove ? alpha : inCheck ? mated_in(ss->ply) : VALUE_DRAW;
+        return  excludedMove ? alpha
+              : inCheck ? mated_in(ss->ply) : DrawValue[pos.side_to_move()];
 
     // If we have pruned all the moves without searching return a fail-low score
     if (bestValue == -VALUE_INFINITE)
@@ -1111,6 +1118,8 @@ split_point_start: // At split points actual search starts from here
             : ttValue >= beta ? (tte->type() & BOUND_LOWER)
                               : (tte->type() & BOUND_UPPER)))
     {
+        assert(ttValue != VALUE_NONE); // Due to ttDepth > DEPTH_NONE
+
         ss->currentMove = ttMove; // Can be MOVE_NONE
         return ttValue;
     }
@@ -1368,13 +1377,10 @@ split_point_start: // At split points actual search starts from here
 
   Value value_to_tt(Value v, int ply) {
 
-    if (v >= VALUE_MATE_IN_MAX_PLY)
-      return v + ply;
+    assert(v != VALUE_NONE);
 
-    if (v <= VALUE_MATED_IN_MAX_PLY)
-      return v - ply;
-
-    return v;
+    return  v >= VALUE_MATE_IN_MAX_PLY  ? v + ply
+          : v <= VALUE_MATED_IN_MAX_PLY ? v - ply : v;
   }
 
 
@@ -1384,13 +1390,9 @@ split_point_start: // At split points actual search starts from here
 
   Value value_from_tt(Value v, int ply) {
 
-    if (v >= VALUE_MATE_IN_MAX_PLY)
-      return v - ply;
-
-    if (v <= VALUE_MATED_IN_MAX_PLY)
-      return v + ply;
-
-    return v;
+    return  v == VALUE_NONE             ? VALUE_NONE
+          : v >= VALUE_MATE_IN_MAX_PLY  ? v - ply
+          : v <= VALUE_MATED_IN_MAX_PLY ? v + ply : v;
   }
 
 
@@ -1435,11 +1437,13 @@ split_point_start: // At split points actual search starts from here
 
 
   // refine_eval() returns the transposition table score if possible, otherwise
-  // falls back on static position evaluation.
+  // falls back on static position evaluation. Note that we never return VALUE_NONE
+  // even if v == VALUE_NONE.
 
   Value refine_eval(const TTEntry* tte, Value v, Value defaultEval) {
 
       assert(tte);
+      assert(v != VALUE_NONE || !tte->type());
 
       if (   ((tte->type() & BOUND_LOWER) && v >= defaultEval)
           || ((tte->type() & BOUND_UPPER) && v < defaultEval))