Retire linear imbalance

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index ff31e0360a76c2c5201cd13e8944024054980fc0..7fafe933d5fda20eb2f9d60bb678c0cc796e4d81 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -725,8 +725,8 @@ namespace {
     // Step 6. Razoring (skipped when in check)
     if (   !PvNode
         &&  depth < 4 * ONE_PLY
-        &&  eval + razor_margin[depth / ONE_PLY] <= alpha
-        &&  ttMove == MOVE_NONE)
+        &&  ttMove == MOVE_NONE
+        &&  eval + razor_margin[depth / ONE_PLY] <= alpha)
     {
         if (   depth <= ONE_PLY
             && eval + razor_margin[3 * ONE_PLY] <= alpha)
@@ -788,9 +788,8 @@ namespace {
     }
 
     // Step 9. ProbCut (skipped when in check)
-    // If we have a very good capture (i.e. SEE > seeValues[captured_piece_type])
-    // and a reduced search returns a value much above beta, we can (almost)
-    // safely prune the previous move.
+    // If we have a good enough capture and a reduced search returns a value
+    // much above beta, we can (almost) safely prune the previous move.
     if (   !PvNode
         &&  depth >= 5 * ONE_PLY
         &&  abs(beta) < VALUE_MATE_IN_MAX_PLY)
@@ -802,7 +801,7 @@ namespace {
         assert((ss-1)->currentMove != MOVE_NONE);
         assert((ss-1)->currentMove != MOVE_NULL);
 
-        MovePicker mp(pos, ttMove, PieceValue[MG][pos.captured_piece_type()]);
+        MovePicker mp(pos, ttMove, rbeta - ss->staticEval);
 
         while ((move = mp.next_move()) != MOVE_NONE)
             if (pos.legal(move))
@@ -925,8 +924,8 @@ moves_loop: // When in check search starts from here
           && !captureOrPromotion
           && !inCheck
           && !givesCheck
-          && !pos.advanced_pawn_push(move)
-          &&  bestValue > VALUE_MATED_IN_MAX_PLY)
+          &&  bestValue > VALUE_MATED_IN_MAX_PLY
+          && !pos.advanced_pawn_push(move))
       {
           // Move count based pruning
           if (moveCountPruning)
@@ -936,7 +935,6 @@ moves_loop: // When in check search starts from here
 
           // Countermoves based pruning
           if (   predictedDepth < 3 * ONE_PLY
-              && move != ss->killers[0]
               && (!cmh  || (*cmh )[moved_piece][to_sq(move)] < VALUE_ZERO)
               && (!fmh  || (*fmh )[moved_piece][to_sq(move)] < VALUE_ZERO)
               && (!fmh2 || (*fmh2)[moved_piece][to_sq(move)] < VALUE_ZERO || (cmh && fmh)))