X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=b180f797b56032c74d122c5cd236755b27be9909;hp=595eee2983b087e428ec0f09156e88189028a298;hb=2ea7449f2a328213b85e043f2de9697d4517d6f7;hpb=787d3585548ed7dac06597780a7d0adb64482d41

diff --git a/src/material.cpp b/src/material.cpp
index 595eee29..b180f797 100644
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -143,7 +143,8 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) {
   }
 
   // Let's look if we have a specialized evaluation function for this
-  // particular material configuration.
+  // particular material configuration. First we look for a fixed
+  // configuration one, then a generic one if previous search failed.
   if ((mi->evaluationFunction = funcs->getEEF(key)) != NULL)
       return mi;
 
@@ -161,6 +162,22 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) {
       mi->evaluationFunction = &EvaluateKKX;
       return mi;
   }
+  else if (   pos.pawns() == EmptyBoardBB
+           && pos.rooks() == EmptyBoardBB
+           && pos.queens() == EmptyBoardBB)
+  {
+      // Minor piece endgame with at least one minor piece per side,
+      // and no pawns.
+      assert(pos.knights(WHITE) | pos.bishops(WHITE));
+      assert(pos.knights(BLACK) | pos.bishops(BLACK));
+
+      if (   pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2
+          && pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2)
+      {
+          mi->evaluationFunction = &EvaluateKmmKm;
+          return mi;
+      }
+  }
 
   // OK, we didn't find any special evaluation function for the current
   // material configuration. Is there a suitable scaling function?
@@ -221,6 +238,18 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) {
       }
   }
 
+  // Compute the space weight
+  if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >=
+      2*QueenValueMidgame + 4*RookValueMidgame + 2*KnightValueMidgame)
+  {
+      int minorPieceCount =  pos.piece_count(WHITE, KNIGHT)
+                           + pos.piece_count(BLACK, KNIGHT)
+                           + pos.piece_count(WHITE, BISHOP)
+                           + pos.piece_count(BLACK, BISHOP);
+
+      mi->spaceWeight = minorPieceCount * minorPieceCount;
+  }
+
   // Evaluate the material balance
 
   int sign;
@@ -281,7 +310,7 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) {
 
 
 /// EndgameFunctions member definitions. This class is used to store the maps
-/// of end game and scaling functions that MaterialInfoTable will query for 
+/// of end game and scaling functions that MaterialInfoTable will query for
 /// each key. The maps are constant and are populated only at construction,
 /// but are per-thread instead of globals to avoid expensive locks.
 
@@ -309,6 +338,8 @@ EndgameFunctions::EndgameFunctions() {
   add(z[W][KNIGHT][1] ^ z[B][ROOK][1],   &EvaluateKNKR);
   add(z[W][QUEEN][1]  ^ z[B][ROOK][1],   &EvaluateKQKR);
   add(z[W][ROOK][1]   ^ z[B][QUEEN][1],  &EvaluateKRKQ);
+  add(z[W][BISHOP][2] ^ z[B][KNIGHT][1], &EvaluateKBBKN);
+  add(z[W][KNIGHT][1] ^ z[B][BISHOP][2], &EvaluateKNKBB);
 
   add(z[W][KNIGHT][1] ^ z[W][PAWN][1], W, &ScaleKNPK);
   add(z[B][KNIGHT][1] ^ z[B][PAWN][1], B, &ScaleKKNP);