From: loco-loco <loco-loco@users.noreply.github.com>
Date: Wed, 18 May 2016 06:46:05 +0000 (-0700)
Subject: Assorted pruning tweaks
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=7cb8cbb403160c8436385149cf1d6949665b4924;ds=sidebyside

Assorted pruning tweaks

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 38257 W: 5206 L: 4961 D: 28090

STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 16550 W: 3110 L: 2914 D: 10526

Bench: 8428997
---

diff --git a/src/search.cpp b/src/search.cpp
index 2828ccda..3b384e86 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -609,6 +609,7 @@ namespace {
     Value bestValue, value, ttValue, eval, nullValue, futilityValue;
     bool ttHit, inCheck, givesCheck, singularExtensionNode, improving;
     bool captureOrPromotion, doFullDepthSearch;
+    Piece moved_piece;
     int moveCount, quietCount;
 
     // Step 1. Initialize node
@@ -864,7 +865,9 @@ namespace {
 moves_loop: // When in check search starts from here
 
     Square prevSq = to_sq((ss-1)->currentMove);
-    const CounterMoveStats& cmh = CounterMoveHistory[pos.piece_on(prevSq)][prevSq];
+    const CounterMoveStats* cmh  = (ss-1)->counterMoves;
+    const CounterMoveStats* fmh  = (ss-2)->counterMoves;
+    const CounterMoveStats* fmh2 = (ss-4)->counterMoves;
 
     MovePicker mp(pos, ttMove, depth, ss);
     CheckInfo ci(pos);
@@ -910,6 +913,7 @@ moves_loop: // When in check search starts from here
 
       extension = DEPTH_ZERO;
       captureOrPromotion = pos.capture_or_promotion(move);
+      moved_piece = pos.moved_piece(move);
 
       givesCheck =  type_of(move) == NORMAL && !ci.dcCandidates
                   ? ci.checkSquares[type_of(pos.piece_on(from_sq(move)))] & to_sq(move)
@@ -956,11 +960,12 @@ moves_loop: // When in check search starts from here
               && moveCount >= FutilityMoveCounts[improving][depth])
               continue;
 
-          // History based pruning
+          // Countermoves based pruning
           if (   depth <= 4 * ONE_PLY
               && move != ss->killers[0]
-              && thisThread->history[pos.moved_piece(move)][to_sq(move)] < VALUE_ZERO
-              && cmh[pos.moved_piece(move)][to_sq(move)] < VALUE_ZERO)
+              && (!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)))
               continue;
 
           predictedDepth = std::max(newDepth - reduction<PvNode>(improving, depth, moveCount), DEPTH_ZERO);
@@ -993,7 +998,7 @@ moves_loop: // When in check search starts from here
       }
 
       ss->currentMove = move;
-      ss->counterMoves = &CounterMoveHistory[pos.moved_piece(move)][to_sq(move)];
+      ss->counterMoves = &CounterMoveHistory[moved_piece][to_sq(move)];
 
       // Step 14. Make the move
       pos.do_move(move, st, givesCheck);
@@ -1005,20 +1010,17 @@ moves_loop: // When in check search starts from here
           && !captureOrPromotion)
       {
           Depth r = reduction<PvNode>(improving, depth, moveCount);
-          Value hValue = thisThread->history[pos.piece_on(to_sq(move))][to_sq(move)];
-          Value cmhValue = cmh[pos.piece_on(to_sq(move))][to_sq(move)];
-
-          const CounterMoveStats* fm = (ss - 2)->counterMoves;
-          const CounterMoveStats* fm2 = (ss - 4)->counterMoves;
-          Value fmValue = (fm ? (*fm)[pos.piece_on(to_sq(move))][to_sq(move)] : VALUE_ZERO);
-          Value fm2Value = (fm2 ? (*fm2)[pos.piece_on(to_sq(move))][to_sq(move)] : VALUE_ZERO);
+          Value val = thisThread->history[moved_piece][to_sq(move)]
+                     +    (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);
 
           // Increase reduction for cut nodes
           if (!PvNode && cutNode)
               r += ONE_PLY;
 
           // Decrease/increase reduction for moves with a good/bad history
-          int rHist = (hValue + cmhValue + fmValue + fm2Value - 10000) / 20000;
+          int rHist = (val - 10000) / 20000;
           r = std::max(DEPTH_ZERO, r - rHist * ONE_PLY);
 
           // Decrease reduction for moves that escape a capture. Filter out