Use gain table to order non-captures

Gain value is multiplied by 16 to be of comparable magnitudo of negative history, on average. This patch shows very good results in tactical tests, but started very bad in real games, so I have run two test matches. After 896 games at 1+0 Mod vs Orig +187 =525 -184 +1 ELO After 999 games at 1+0 Mod vs Orig +223 =590 -186 +13 ELO Signed-off-by: Marco Costalba <mcostalba@gmail.com>
mcostalba · Feb 7, 2010 · 2e70a28 · 2e70a28
1 parent 9429d2d
commit 2e70a28
Showing 1 changed file with 9 additions and 1 deletion.
diff --git a/src/movepick.cpp b/src/movepick.cpp
@@ -213,14 +213,22 @@ void MovePicker::score_noncaptures() {
   Move m;
   Piece piece;
   Square from, to;
+  int hs;
 
   for (MoveStack* cur = moves; cur != lastMove; cur++)
   {
       m = cur->move;
       from = move_from(m);
       to = move_to(m);
       piece = pos.piece_on(from);
-      cur->score = H.move_ordering_score(piece, to);
+      hs = H.move_ordering_score(piece, to);
+
+      // Ensure history has always highest priority
+      if (hs > 0)
+          hs += 10000;
+
+      // Gain table based scoring
+      cur->score = hs + 16 * H.gain(piece, to);
   }
 }