Knight threats on Queen

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index f7c13bbf24ecb816b87a2f4d540a9e695dc91393..30f77bd9af80c10155af469acf9afce9ff86304e 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -682,20 +682,21 @@ namespace {
         goto moves_loop;
 
     // Step 7. Razoring (skipped when in check)
-    if (   !PvNode
-        &&  depth <= ONE_PLY)
+    if (  !PvNode
+        && depth <= 2 * ONE_PLY)
     {
-        if (eval + RazorMargin1 <= alpha)
+        if (   depth == ONE_PLY
+            && eval + RazorMargin1 <= alpha)
             return qsearch<NonPV, false>(pos, ss, alpha, alpha+1);
-    }
-    else if (   !PvNode
-             &&  depth <= 2 * ONE_PLY
-             &&  eval + RazorMargin2 <= alpha)
-    {
-        Value ralpha = alpha - RazorMargin2;
-        Value v = qsearch<NonPV, false>(pos, ss, ralpha, ralpha+1);
-        if (v <= ralpha)
-            return v;
+
+        else if (eval + RazorMargin2 <= alpha)
+        {
+            Value ralpha = alpha - RazorMargin2;
+            Value v = qsearch<NonPV, false>(pos, ss, ralpha, ralpha+1);
+
+            if (v <= ralpha)
+                return v;
+        }
     }
 
     // Step 8. Futility pruning: child node (skipped when in check)
@@ -760,6 +761,7 @@ namespace {
         Value rbeta = std::min(beta + 200, VALUE_INFINITE);
         MovePicker mp(pos, ttMove, rbeta - ss->staticEval, &thisThread->captureHistory);
         int probCutCount = 0;
+
         while (  (move = mp.next_move()) != MOVE_NONE
                && probCutCount < depth / ONE_PLY - 3)
             if (pos.legal(move))
@@ -785,6 +787,7 @@ namespace {
                     value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, depth - 4 * ONE_PLY, !cutNode, false);
 
                 pos.undo_move(move);
+
                 if (value >= rbeta)
                     return value;
             }