LMR Simplification

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 4a52e62658f0deccce3eea3c1287b9d87b3147fa..09f06d2983e0b644bf9dadd94fa6efc7baae1051 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -187,6 +187,7 @@ namespace {
   const Score OtherCheck          = S(10, 10);
   const Score ThreatByHangingPawn = S(71, 61);
   const Score LooseEnemies        = S( 0, 25);
+  const Score WeakQueen           = S(35,  0);
   const Score Hanging             = S(48, 27);
   const Score ThreatByPawnPush    = S(38, 22);
   const Score Unstoppable         = S( 0, 20);
@@ -210,10 +211,10 @@ namespace {
 
   // Penalties for enemy's safe checks
   const int QueenContactCheck = 89;
-  const int QueenCheck        = 52;
-  const int RookCheck         = 45;
-  const int BishopCheck       = 5;
-  const int KnightCheck       = 17;
+  const int QueenCheck        = 62;
+  const int RookCheck         = 57;
+  const int BishopCheck       = 48;
+  const int KnightCheck       = 78;
 
 
   // eval_init() initializes king and attack bitboards for a given color
@@ -398,8 +399,8 @@ namespace {
         // the pawn shelter (current 'score' value).
         attackUnits =  std::min(72, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
                      +  9 * ei.kingAdjacentZoneAttacksCount[Them]
-                     + 27 * popcount(undefended)
-                     + 11 * (popcount(b) + !!ei.pinnedPieces[Us])
+                     + 21 * popcount(undefended)
+                     + 12 * (popcount(b) + !!ei.pinnedPieces[Us])
                      - 64 * !pos.count<QUEEN>(Them)
                      - mg_value(score) / 8;
 
@@ -488,6 +489,13 @@ namespace {
         & ~(ei.attackedBy[Us][ALL_PIECES] | ei.attackedBy[Them][ALL_PIECES]))
         score += LooseEnemies;
 
+    // Bonus for pin or discovered attack on the opponent queen
+    if (   pos.count<QUEEN>(Them) == 1
+        && pos.slider_blockers(pos.pieces(),
+                               pos.pieces(Us, ROOK, BISHOP),
+                               pos.square<QUEEN>(Them)))
+        score += WeakQueen;
+
     // Non-pawn enemies attacked by a pawn
     weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Us][PAWN];