Adjust reduction less at medium depths

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 7019635dd34b6f4015822541621174fe5b90cb11..422d4b43a8268b702dd02943bb434c78e0d99262 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -775,8 +775,7 @@ namespace {
     // Step 7. Razoring.
     // If eval is really low check with qsearch if it can exceed alpha, if it can't,
     // return a fail low.
-    if (   depth <= 7
-        && eval < alpha - 369 - 254 * depth * depth)
+    if (eval < alpha - 369 - 254 * depth * depth)
     {
         value = qsearch<NonPV>(pos, ss, alpha - 1, alpha);
         if (value < alpha)
@@ -1178,7 +1177,7 @@ moves_loop: // When in check, search starts here
                          - 4433;
 
           // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
-          r -= ss->statScore / 13628;
+          r -= ss->statScore / (13628 + 4000 * (depth > 7 && depth < 19));
 
           // In general we want to cap the LMR depth search at newDepth, but when
           // reduction is negative, we allow this move a limited search extension
@@ -1549,8 +1548,8 @@ moves_loop: // When in check, search starts here
       // Continuation history based pruning (~2 Elo)
       if (   !capture
           && bestValue > VALUE_TB_LOSS_IN_MAX_PLY
-          && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold
-          && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold)
+          && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < 0
+          && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < 0)
           continue;
 
       // movecount pruning for quiet check evasions