From: Marco Costalba <mcostalba@gmail.com>
Date: Sun, 26 Oct 2008 12:44:34 +0000 (+0100)
Subject: Reintroduce piece/square tables to score non-captures
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=88885399f4a8bdc579c2b75cd892e78821631c63;hp=a5c1b3e8f68a9c98e6be1f90e7d0295d05c685de

Reintroduce piece/square tables to score non-captures

Was removed after original movepick restore. But proved
to be useful.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 68f03a30..2867e766 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -226,16 +226,28 @@ void MovePicker::score_captures() {
 }
 
 void MovePicker::score_noncaptures() {
-
-  for (int i = 0; i < numOfMoves; i++)
-  {
-      Move m = moves[i].move;
-      if (m == killer1)
-          moves[i].score = HistoryMax + 2;
-      else if (m == killer2)
-          moves[i].score = HistoryMax + 1;
-      else
-         moves[i].score = H.move_ordering_score(pos.piece_on(move_from(m)), m);
+  // First score by history, when no history is available then use
+  // piece/square tables values. This seems to be better then a
+  // random choice when we don't have an history for any move.
+  Move m;
+  int hs;
+
+  for (int i = 0; i < numOfMoves; i++)
+  {
+      m = moves[i].move;
+
+      if (m == killer1)
+          hs = HistoryMax + 2;
+      else if (m == killer2)
+          hs = HistoryMax + 1;
+      else
+          hs = H.move_ordering_score(pos.piece_on(move_from(m)), m);
+
+      // Ensure moves in history are always sorted as first
+      if (hs > 0)
+          hs += 1000;
+
+      moves[i].score = hs + pos.mg_pst_delta(m);
   }
 }