Remove Gain Stats

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 152e9fd68c4812854d0ce3d098581586fb56102f..814a96d98cb66abed49d617566001b350d349798 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -134,7 +134,6 @@ namespace {
   Value DrawValue[COLOR_NB];
   HistoryStats History;
   CounterMovesHistoryStats CounterMovesHistory;
-  GainsStats Gains;
   MovesStats Countermoves;
 
   template <NodeType NT, bool SpNode>
@@ -181,15 +180,14 @@ void Search::init() {
 }
 
 
-/// Search::reset() clears all search memory, to restore a deterministic state
+/// Search::reset() clears all search memory, to obtain reproducible search results
 
 void Search::reset () {
 
-    TT.clear();
-    History.clear();
-    CounterMovesHistory.clear();
-    Gains.clear();
-    Countermoves.clear();
+  TT.clear();
+  History.clear();
+  CounterMovesHistory.clear();
+  Countermoves.clear();
 }
 
 
@@ -643,7 +641,7 @@ namespace {
         }
     }
 
-    // Step 5. Evaluate the position statically and update parent's gain statistics
+    // Step 5. Evaluate the position statically
     if (inCheck)
     {
         ss->staticEval = eval = VALUE_NONE;
@@ -672,17 +670,6 @@ namespace {
     if (ss->skipEarlyPruning)
         goto moves_loop;
 
-    if (   !pos.captured_piece_type()
-        &&  ss->staticEval != VALUE_NONE
-        && (ss-1)->staticEval != VALUE_NONE
-        && (move = (ss-1)->currentMove) != MOVE_NULL
-        &&  move != MOVE_NONE
-        &&  type_of(move) == NORMAL)
-    {
-        Square to = to_sq(move);
-        Gains.update(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
-    }
-
     // Step 6. Razoring (skipped when in check)
     if (   !PvNode
         &&  depth < 4 * ONE_PLY
@@ -858,7 +845,7 @@ moves_loop: // When in check and at SpNode search starts from here
       captureOrPromotion = pos.capture_or_promotion(move);
 
       givesCheck =  type_of(move) == NORMAL && !ci.dcCandidates
-                  ? ci.checkSq[type_of(pos.piece_on(from_sq(move)))] & to_sq(move)
+                  ? ci.checkSquares[type_of(pos.piece_on(from_sq(move)))] & to_sq(move)
                   : pos.gives_check(move, ci);
 
       dangerous =   givesCheck
@@ -915,8 +902,7 @@ moves_loop: // When in check and at SpNode search starts from here
           // Futility pruning: parent node
           if (predictedDepth < 7 * ONE_PLY)
           {
-              futilityValue =  ss->staticEval + futility_margin(predictedDepth)
-                             + 128 + Gains[pos.moved_piece(move)][to_sq(move)];
+              futilityValue =  ss->staticEval + futility_margin(predictedDepth) + 256;
 
               if (futilityValue <= alpha)
               {
@@ -1281,7 +1267,7 @@ moves_loop: // When in check and at SpNode search starts from here
       assert(is_ok(move));
 
       givesCheck =  type_of(move) == NORMAL && !ci.dcCandidates
-                  ? ci.checkSq[type_of(pos.piece_on(from_sq(move)))] & to_sq(move)
+                  ? ci.checkSquares[type_of(pos.piece_on(from_sq(move)))] & to_sq(move)
                   : pos.gives_check(move, ci);
 
       // Futility pruning