Tweak initiative formula

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 826e860a5c22d3441424f63fd674c2aaa5b624d1..e8d3834343bc33215357310f3eedf304dce62260 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -679,11 +679,12 @@ namespace {
   // status of the players.
   Score evaluate_initiative(const Position& pos, int asymmetry, Value eg) {
 
-    int kingDistance = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
+    int kingDistance =   distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
+                       - distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
     int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
 
     // Compute the initiative bonus for the attacking side
-    int initiative = 8 * (pawns + asymmetry + kingDistance - 15);
+    int initiative = 8 * (asymmetry + kingDistance) + 12 * pawns - 120;
 
     // Now apply the bonus: note that we find the attacking side by extracting
     // the sign of the endgame value, and that we carefully cap the bonus so