Adjust LMR with correction history

A positive constant increase in base reduction is applied to counter the
decrease in average reduction from this tweak.

Passed STC:
LLR: 2.98 (-2.94,2.94) <0.00,2.00>
Total: 109216 W: 28415 L: 27989 D: 52812
Ptnml(0-2): 310, 12848, 27911, 13184, 355
https://tests.stockfishchess.org/tests/view/6760bb0e86d5ee47d9542f26

Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 66918 W: 17073 L: 16694 D: 33151
Ptnml(0-2): 33, 7175, 18666, 7550, 35
https://tests.stockfishchess.org/tests/view/6761e10f86d5ee47d95431fa

closes https://github.com/official-stockfish/Stockfish/pull/5727

Bench: 1294909

src/search.cpp

@@ -77,9 +77,7 @@ constexpr int futility_move_count(bool improving, Depth depth) {
     return (3 + depth * depth) / (2 - improving);
 }
 
-// Add correctionHistory value to raw staticEval and guarantee evaluation
+int correction_value(const Worker& w, const Position& pos, Stack* ss) {
-// does not hit the tablebase range.
-Value to_corrected_static_eval(Value v, const Worker& w, const Position& pos, Stack* ss) {
     const Color us    = pos.side_to_move();
     const auto  m     = (ss - 1)->currentMove;
     const auto  pcv   = w.pawnCorrectionHistory[us][pawn_structure_index<Correction>(pos)];
@@ -87,15 +85,17 @@ Value to_corrected_static_eval(Value v, const Worker& w, const Position& pos, St
     const auto  micv  = w.minorPieceCorrectionHistory[us][minor_piece_index(pos)];
     const auto  wnpcv = w.nonPawnCorrectionHistory[WHITE][us][non_pawn_index<WHITE>(pos)];
     const auto  bnpcv = w.nonPawnCorrectionHistory[BLACK][us][non_pawn_index<BLACK>(pos)];
-    int         cntcv = 1;
+    const auto  cntcv =
+      m.is_ok() ? (*(ss - 2)->continuationCorrectionHistory)[pos.piece_on(m.to_sq())][m.to_sq()]
+                 : 0;
 
-    if (m.is_ok())
+    return (6384 * pcv + 3583 * macv + 6492 * micv + 6725 * (wnpcv + bnpcv) + 5880 * cntcv);
-        cntcv = int((*(ss - 2)->continuationCorrectionHistory)[pos.piece_on(m.to_sq())][m.to_sq()]);
+}
 
-    const auto cv =
+// Add correctionHistory value to raw staticEval and guarantee evaluation
-      (6384 * pcv + 3583 * macv + 6492 * micv + 6725 * (wnpcv + bnpcv) + cntcv * 5880) / 131072;
+// does not hit the tablebase range.
-    v += cv;
+Value to_corrected_static_eval(Value v, const int cv) {
-    return std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
+    return std::clamp(v + cv / 131072, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
 }
 
 // History and stats update bonus, based on depth
@@ -710,6 +710,7 @@ Value Search::Worker::search(
 
     // Step 6. Static evaluation of the position
     Value      unadjustedStaticEval = VALUE_NONE;
+    const auto correctionValue      = correction_value(*thisThread, pos, ss);
     if (ss->inCheck)
     {
         // Skip early pruning when in check
@@ -733,8 +734,7 @@ Value Search::Worker::search(
         else if (PvNode)
             Eval::NNUE::hint_common_parent_position(pos, networks[numaAccessToken], refreshTable);
 
-        ss->staticEval = eval =
+        ss->staticEval = eval = to_corrected_static_eval(unadjustedStaticEval, correctionValue);
-          to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos, ss);
 
         // ttValue can be used as a better position evaluation (~7 Elo)
         if (is_valid(ttData.value)
@@ -744,8 +744,7 @@ Value Search::Worker::search(
     else
     {
         unadjustedStaticEval = evaluate(pos);
-        ss->staticEval       = eval =
+        ss->staticEval = eval = to_corrected_static_eval(unadjustedStaticEval, correctionValue);
-          to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos, ss);
 
         // Static evaluation is saved as it was before adjustment by correction history
         ttWriter.write(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_UNSEARCHED, Move::none(),
@@ -1155,6 +1154,10 @@ moves_loop:  // When in check, search starts here
 
         // These reduction adjustments have no proven non-linear scaling
 
+        r += 330;
+
+        r -= std::min(std::abs(correctionValue) / 32768, 2048);
+
         // Increase reduction for cut nodes (~4 Elo)
         if (cutNode)
             r += 2518 - (ttData.depth >= depth && ss->ttPv) * 991;
@@ -1526,6 +1529,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta)
 
     // Step 4. Static evaluation of the position
     Value      unadjustedStaticEval = VALUE_NONE;
+    const auto correctionValue      = correction_value(*thisThread, pos, ss);
     if (ss->inCheck)
         bestValue = futilityBase = -VALUE_INFINITE;
     else
@@ -1537,7 +1541,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta)
             if (!is_valid(unadjustedStaticEval))
                 unadjustedStaticEval = evaluate(pos);
             ss->staticEval = bestValue =
-              to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos, ss);
+              to_corrected_static_eval(unadjustedStaticEval, correctionValue);
 
             // ttValue can be used as a better position evaluation (~13 Elo)
             if (is_valid(ttData.value) && !is_decisive(ttData.value)
@@ -1550,7 +1554,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta)
             unadjustedStaticEval =
               (ss - 1)->currentMove != Move::null() ? evaluate(pos) : -(ss - 1)->staticEval;
             ss->staticEval = bestValue =
-              to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos, ss);
+              to_corrected_static_eval(unadjustedStaticEval, correctionValue);
         }
 
         // Stand pat. Return immediately if static value is at least beta