Document Elo impact of various parts of search

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 5f8db7414eb83c064e3679ea8570f40a144f0972..3e0533b20c7d8c730c08976bb5c016f39746b742 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -28,8 +28,7 @@
 #include "evaluate.h"
 #include "material.h"
 #include "pawns.h"
-
-std::atomic<Score> Eval::Contempt;
+#include "thread.h"
 
 namespace Trace {
 
@@ -374,7 +373,7 @@ namespace {
 
         if (Pt == ROOK)
         {
-            // Bonus for aligning rook with with enemy pawns on the same rank/file
+            // Bonus for aligning rook with enemy pawns on the same rank/file
             if (relative_rank(Us, s) >= RANK_5)
                 score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]);
 
@@ -693,7 +692,7 @@ namespace {
             }
             else if (pos.pieces(Us) & blockSq)
                 bonus += make_score(w + r * 2, w + r * 2);
-        } // rr != 0
+        } // w != 0
 
         // Scale down bonus for candidate passers which need more than one
         // pawn push to become passed or have a pawn in front of them.
@@ -801,11 +800,10 @@ namespace {
     {
         if (pos.opposite_bishops())
         {
-            // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
-            // is almost a draw, in case of KBP vs KB, it is even more a draw.
+            // Endgame with opposite-colored bishops and no other pieces is almost a draw
             if (   pos.non_pawn_material(WHITE) == BishopValueMg
                 && pos.non_pawn_material(BLACK) == BishopValueMg)
-                sf = more_than_one(pos.pieces(PAWN)) ? 31 : 9;
+                sf = 31;
 
             // Endgame with opposite-colored bishops, but also other pieces. Still
             // a bit drawish, but not as drawish as with only the two bishops.
@@ -844,7 +842,7 @@ namespace {
     // Initialize score by reading the incrementally updated scores included in
     // the position object (material + piece square tables) and the material
     // imbalance. Score is computed internally from the white point of view.
-    Score score = pos.psq_score() + me->imbalance() + Eval::Contempt;
+    Score score = pos.psq_score() + me->imbalance() + pos.this_thread()->contempt;
 
     // Probe the pawn hash table
     pe = Pawns::probe(pos);
@@ -915,7 +913,7 @@ std::string Eval::trace(const Position& pos) {
 
   std::memset(scores, 0, sizeof(scores));
 
-  Eval::Contempt = SCORE_ZERO; // Reset any dynamic contempt
+  pos.this_thread()->contempt = SCORE_ZERO; // Reset any dynamic contempt
 
   Value v = Evaluation<TRACE>(pos).value();