X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=55df6172c64c779d890431bc6f0f42abab2cc9fb;hp=2d5fb6305b8d84dde21795edd409d2af2d88285c;hb=328bdd0947ea7903ee1061c8eb60bc3121a4eb19;hpb=770c8d92f3886d11ae88afef13f6552f9132a714

diff --git a/src/search.cpp b/src/search.cpp
index 2d5fb630..55df6172 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -86,9 +86,8 @@ namespace {
   }
 
   // Add a small random component to draw evaluations to avoid 3fold-blindness
-  Value value_draw(Depth depth, Thread* thisThread) {
-    return depth < 4 * ONE_PLY ? VALUE_DRAW
-                               : VALUE_DRAW + Value(2 * (thisThread->nodes & 1) - 1);
+  Value value_draw(Thread* thisThread) {
+    return VALUE_DRAW + Value(2 * (thisThread->nodes & 1) - 1);
   }
 
   // Skill structure is used to implement strength limit
@@ -192,7 +191,7 @@ namespace {
 void Search::init() {
 
   for (int i = 1; i < MAX_MOVES; ++i)
-      Reductions[i] = int(23.4 * std::log(i));
+      Reductions[i] = int((23.4 + std::log(Threads.size()) / 2) * std::log(i));
 }
 
 
@@ -574,7 +573,7 @@ namespace {
         && !rootNode
         && pos.has_game_cycle(ss->ply))
     {
-        alpha = value_draw(depth, pos.this_thread());
+        alpha = value_draw(pos.this_thread());
         if (alpha >= beta)
             return alpha;
     }
@@ -624,7 +623,7 @@ namespace {
             || pos.is_draw(ss->ply)
             || ss->ply >= MAX_PLY)
             return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos)
-                                                    : value_draw(depth, pos.this_thread());
+                                                    : value_draw(pos.this_thread());
 
         // 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
@@ -763,7 +762,7 @@ namespace {
             ss->staticEval = eval = evaluate(pos);
 
         if (eval == VALUE_DRAW)
-            eval = value_draw(depth, thisThread);
+            eval = value_draw(thisThread);
 
         // Can ttValue be used as a better position evaluation?
         if (    ttValue != VALUE_NONE
@@ -997,10 +996,6 @@ moves_loop: // When in check, search starts from here
                && (pos.is_discovery_check_on_king(~us, move) || pos.see_ge(move)))
           extension = ONE_PLY;
 
-      // Castling extension
-      else if (type_of(move) == CASTLING)
-          extension = ONE_PLY;
-
       // Shuffle extension
       else if (   PvNode
                && pos.rule50_count() > 18
@@ -1014,6 +1009,10 @@ moves_loop: // When in check, search starts from here
                && pos.pawn_passed(us, to_sq(move)))
           extension = ONE_PLY;
 
+      // Castling extension
+      if (type_of(move) == CASTLING)
+          extension = ONE_PLY;
+
       // Calculate new depth for this move
       newDepth = depth - ONE_PLY + extension;