doEvenDeeperSearch + tuning

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 5839763dc7fd647fa8e91d92cb874e54368c1126..343c098a587dbb6cf3d8b8eb6aae946d178d733b 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -81,7 +81,7 @@ namespace {
 
   // History and stats update bonus, based on depth
   int stat_bonus(Depth d) {
-    return std::min((12 * d + 282) * d - 349 , 1594);
+    return std::min((12 * d + 282) * d - 349 , 1480);
   }
 
   // Add a small random component to draw evaluations to avoid 3-fold blindness
@@ -244,7 +244,7 @@ void MainThread::search() {
 
   // Send again PV info if we have a new best thread
   if (bestThread != this)
-      sync_cout << UCI::pv(bestThread->rootPos, bestThread->completedDepth, -VALUE_INFINITE, VALUE_INFINITE) << sync_endl;
+      sync_cout << UCI::pv(bestThread->rootPos, bestThread->completedDepth) << sync_endl;
 
   sync_cout << "bestmove " << UCI::move(bestThread->rootMoves[0].pv[0], rootPos.is_chess960());
 
@@ -392,7 +392,7 @@ void Thread::search() {
                   && multiPV == 1
                   && (bestValue <= alpha || bestValue >= beta)
                   && Time.elapsed() > 3000)
-                  sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl;
+                  sync_cout << UCI::pv(rootPos, rootDepth) << sync_endl;
 
               // In case of failing low/high increase aspiration window and
               // re-search, otherwise exit the loop.
@@ -423,7 +423,7 @@ void Thread::search() {
 
           if (    mainThread
               && (Threads.stop || pvIdx + 1 == multiPV || Time.elapsed() > 3000))
-              sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl;
+              sync_cout << UCI::pv(rootPos, rootDepth) << sync_endl;
       }
 
       if (!Threads.stop)
@@ -855,7 +855,7 @@ namespace {
     {
         assert(probCutBeta < VALUE_INFINITE);
 
-        MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, depth - 3, &captureHistory);
+        MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory);
 
         while ((move = mp.next_move()) != MOVE_NONE)
             if (move != excludedMove && pos.legal(move))
@@ -1156,13 +1156,13 @@ moves_loop: // When in check, search starts here
           if (singularQuietLMR)
               r--;
 
-          // Dicrease reduction if we move a threatened piece (~1 Elo)
+          // Decrease reduction if we move a threatened piece (~1 Elo)
           if (   depth > 9
               && (mp.threatenedPieces & from_sq(move)))
               r--;
 
           // Increase reduction if next ply has a lot of fail high
-          if ((ss+1)->cutoffCnt > 3 && !PvNode)
+          if ((ss+1)->cutoffCnt > 3)
               r++;
 
           ss->statScore =  2 * thisThread->mainHistory[us][from_to(move)]
@@ -1172,7 +1172,7 @@ 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 + 4000 * (depth > 7 && depth < 19));
+          r -= ss->statScore / (13000 + 4152 * (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
@@ -1187,8 +1187,13 @@ moves_loop: // When in check, search starts here
               // Adjust full depth search based on LMR results - if result
               // was good enough search deeper, if it was bad enough search shallower
               const bool doDeeperSearch = value > (alpha + 64 + 11 * (newDepth - d));
+              const bool doEvenDeeperSearch = value > alpha + 582;
               const bool doShallowerSearch = value < bestValue + newDepth;
-              value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth + doDeeperSearch - doShallowerSearch, !cutNode);
+
+              newDepth += doDeeperSearch - doShallowerSearch + doEvenDeeperSearch;
+
+              if (newDepth > d)
+                  value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
 
               int bonus = value > alpha ?  stat_bonus(newDepth)
                                         : -stat_bonus(newDepth);
@@ -1242,6 +1247,8 @@ moves_loop: // When in check, search starts here
           {
               rm.score = value;
               rm.selDepth = thisThread->selDepth;
+              rm.scoreLowerbound = value >= beta;
+              rm.scoreUpperbound = value <= alpha;
               rm.pv.resize(1);
 
               assert((ss+1)->pv);
@@ -1295,8 +1302,6 @@ moves_loop: // When in check, search starts here
               }
           }
       }
-      else
-         ss->cutoffCnt = 0;
 
 
       // If the move is worse than some previously searched move, remember it to update its stats later
@@ -1550,12 +1555,11 @@ moves_loop: // When in check, search starts here
           && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < 0)
           continue;
 
-      // movecount pruning for quiet check evasions
+      // We prune after 2nd quiet check evasion where being 'in check' is implicitly checked through the counter
+      // and being a 'quiet' apart from being a tt move is assumed after an increment because captures are pushed ahead.
       if (   bestValue > VALUE_TB_LOSS_IN_MAX_PLY
-          && quietCheckEvasions > 1
-          && !capture
-          && ss->inCheck)
-          continue;
+          && quietCheckEvasions > 1)
+          break;
 
       quietCheckEvasions += !capture && ss->inCheck;
 
@@ -1819,7 +1823,7 @@ void MainThread::check_time() {
 /// UCI::pv() formats PV information according to the UCI protocol. UCI requires
 /// that all (if any) unsearched PV lines are sent using a previous search score.
 
-string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) {
+string UCI::pv(const Position& pos, Depth depth) {
 
   std::stringstream ss;
   TimePoint elapsed = Time.elapsed() + 1;
@@ -1857,8 +1861,8 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) {
       if (Options["UCI_ShowWDL"])
           ss << UCI::wdl(v, pos.game_ply());
 
-      if (!tb && i == pvIdx)
-          ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
+      if (i == pvIdx && !tb && updated) // tablebase- and previous-scores are exact
+         ss << (rootMoves[i].scoreLowerbound ? " lowerbound" : (rootMoves[i].scoreUpperbound ? " upperbound" : ""));
 
       ss << " nodes "    << nodesSearched
          << " nps "      << nodesSearched * 1000 / elapsed