Fix Contempt Factor implementation

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index c9a8f58204a4dc9ecddce0f4c3013e1f21b64afd..4d1a6af784d1e41217df9b29c3676c20a55dc6cd 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -199,6 +199,8 @@ void Search::think() {
   Position& pos = RootPosition;
   Chess960 = pos.is_chess960();
   Eval::RootColor = pos.side_to_move();
   Position& pos = RootPosition;
   Chess960 = pos.is_chess960();
   Eval::RootColor = pos.side_to_move();

+  Eval::ValueDraw[ Eval::RootColor] = VALUE_DRAW - Eval::ContemptFactor;
+  Eval::ValueDraw[~Eval::RootColor] = VALUE_DRAW + Eval::ContemptFactor;

   TimeMgr.init(Limits, pos.startpos_ply_counter(), pos.side_to_move());
   TT.new_search();
   H.clear();
   TimeMgr.init(Limits, pos.startpos_ply_counter(), pos.side_to_move());
   TT.new_search();
   H.clear();


@@ -538,7 +540,7 @@ namespace {
     {
         // Step 2. Check for aborted search and immediate draw
         if (Signals.stop || pos.is_draw<false>() || ss->ply > MAX_PLY)
     {
         // Step 2. Check for aborted search and immediate draw
         if (Signals.stop || pos.is_draw<false>() || ss->ply > MAX_PLY)

-            return Eval::ValueDrawContempt;
+            return Eval::ValueDraw[pos.side_to_move()];

 
         // Step 3. Mate distance pruning. Even if we mate at the next move our score
         // would be at best mate_in(ss->ply+1), but if alpha is already bigger because
 
         // Step 3. Mate distance pruning. Even if we mate at the next move our score
         // would be at best mate_in(ss->ply+1), but if alpha is already bigger because


@@ -1094,7 +1096,7 @@ split_point_start: // At split points actual search starts from here
 
     // Check for an instant draw or maximum ply reached
     if (pos.is_draw<true>() || ss->ply > MAX_PLY)
 
     // Check for an instant draw or maximum ply reached
     if (pos.is_draw<true>() || ss->ply > MAX_PLY)

-        return Eval::ValueDrawContempt;
+        return Eval::ValueDraw[pos.side_to_move()];

 
     // Decide whether or not to include checks, this fixes also the type of
     // TT entry depth that we are going to use. Note that in qsearch we use
 
     // Decide whether or not to include checks, this fixes also the type of
     // TT entry depth that we are going to use. Note that in qsearch we use