X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=f52351920a369831119c2fecc65d483e626dfd9a;hp=549f19e211caecc575a10eb6fda327a6986e1d06;hb=1c087dd806b65c5d6668706f0c8fddf14f6fcd41;hpb=ca4e78db8db1288eb5c8deecb9bdf402f53fdc98

diff --git a/src/search.cpp b/src/search.cpp
index 549f19e2..f5235192 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -121,6 +121,9 @@ namespace {
   // Depth limit for selective search:
   Depth SelectiveDepth = 7*OnePly;
 
+  // Use dynamic LMR?
+  const bool UseDynamicLMR = false;
+
   // Use internal iterative deepening?
   const bool UseIIDAtPVNodes = true;
   const bool UseIIDAtNonPVNodes = false;
@@ -193,7 +196,6 @@ namespace {
 
   // Iteration counters
   int Iteration;
-  bool LastIterations;
   BetaCounterType BetaCounter;
 
   // Scores and number of times the best move changed for each iteration:
@@ -207,7 +209,7 @@ namespace {
   int SearchStartTime;
   int MaxNodes, MaxDepth;
   int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime;
-  Move BestRootMove, PonderMove, EasyMove;
+  Move EasyMove;
   int RootMoveNumber;
   bool InfiniteSearch;
   bool PonderSearch;
@@ -369,8 +371,6 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
   // Initialize global search variables
   Idle = false;
   SearchStartTime = get_system_time();
-  BestRootMove = MOVE_NONE;
-  PonderMove = MOVE_NONE;
   EasyMove = MOVE_NONE;
   for (int i = 0; i < THREAD_MAX; i++)
   {
@@ -661,7 +661,6 @@ namespace {
     ValueByIteration[0] = Value(0);
     ValueByIteration[1] = rml.get_move_score(0);
     Iteration = 1;
-    LastIterations = false;
 
     EasyMove = rml.scan_for_easy_move();
 
@@ -716,9 +715,6 @@ namespace {
                 ExtraSearchTime = BestMoveChangesByIteration[Iteration]   * (MaxSearchTime / 2)
                                 + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
 
-            // Try to guess if the current iteration is the last one or the last two
-            LastIterations = (current_search_time() > ((MaxSearchTime + ExtraSearchTime)*58) / 128);
-
             // Stop search if most of MaxSearchTime is consumed at the end of the
             // iteration.  We probably don't have enough time to search the first
             // move at the next iteration anyway.
@@ -755,6 +751,11 @@ namespace {
                   << " hashfull " << TT.full() << std::endl;
 
     // Print the best move and the ponder move to the standard output
+    if (ss[0].pv[0] == MOVE_NONE)
+    {
+        ss[0].pv[0] = rml.get_move(0);
+        ss[0].pv[1] = MOVE_NONE;
+    }
     std::cout << "bestmove " << ss[0].pv[0];
     if (ss[0].pv[1] != MOVE_NONE)
         std::cout << " ponder " << ss[0].pv[1];
@@ -1247,8 +1248,8 @@ namespace {
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
         if (   (v < beta - RazorMargin - RazorMargin / 4)
-            || (depth < 3*OnePly && v < beta - RazorMargin)
-            || (depth < 2*OnePly && v < beta - RazorMargin / 2))
+            || (depth <= 2*OnePly && v < beta - RazorMargin)
+            || (depth <=   OnePly && v < beta - RazorMargin / 2))
             return v;
     }
 
@@ -1334,8 +1335,13 @@ namespace {
           && !move_is_castle(move)
           && !move_is_killer(move, ss[ply]))
       {
-          ss[ply].reduction = OnePly;
-          value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID);
+          // LMR dynamic reduction
+          Depth R =    UseDynamicLMR
+                    && moveCount >= 2 * LMRNonPVMoves
+                    && depth > 7*OnePly ? 2*OnePly : OnePly;
+
+          ss[ply].reduction = R;
+          value = -search(pos, ss, -(beta-1), newDepth-R, ply+1, true, threadID);
       }
       else
         value = beta; // Just to trigger next condition
@@ -1396,6 +1402,9 @@ namespace {
         }
         TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER);
     }
+
+    assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
+
     return bestValue;
   }
 
@@ -1424,10 +1433,14 @@ namespace {
     if (pos.is_draw())
         return VALUE_DRAW;
 
-    // Transposition table lookup
-    const TTEntry* tte = TT.retrieve(pos);
-    if (tte && ok_to_use_TT(tte, depth, beta, ply))
-        return value_from_tt(tte->value(), ply);
+    // Transposition table lookup, only when not in PV
+    bool pvNode = (beta - alpha != 1);
+    if (!pvNode)
+    {
+        const TTEntry* tte = TT.retrieve(pos);
+        if (tte && ok_to_use_TT(tte, depth, beta, ply))
+            return value_from_tt(tte->value(), ply);
+    }
 
     // Evaluate the position statically
     EvalInfo ei;
@@ -1442,7 +1455,11 @@ namespace {
     Value bestValue = staticValue;
 
     if (bestValue >= beta)
+    {
+        // Update transposition table before to leave
+        TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_EXACT);
         return bestValue;
+    }
 
     if (bestValue > alpha)
         alpha = bestValue;
@@ -1450,7 +1467,6 @@ namespace {
     // Initialize a MovePicker object for the current position, and prepare
     // to search the moves.  Because the depth is <= 0 here, only captures,
     // queen promotions and checks (only if depth == 0) will be generated.
-    bool pvNode = (beta - alpha != 1);
     MovePicker mp = MovePicker(pos, pvNode, MOVE_NONE, EmptySearchStack, depth, isCheck ? NULL : &ei);
     Move move;
     int moveCount = 0;
@@ -1527,9 +1543,6 @@ namespace {
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
-    // Update transposition table
-    TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_EXACT);
-
     // Update killers only for good check moves
     Move m = ss[ply].currentMove;
     if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered
@@ -2405,7 +2418,7 @@ namespace {
                      || (  !FailHigh && !fail_high_ply_1() && !Problem
                          && t > 6*(MaxSearchTime + ExtraSearchTime));
 
-    if (   (Iteration >= 2 && (!InfiniteSearch && overTime))
+    if (   (Iteration >= 3 && (!InfiniteSearch && overTime))
         || (ExactMaxTime && t >= ExactMaxTime)
         || (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes))
         AbortSearch = true;
@@ -2419,7 +2432,7 @@ namespace {
   void ponderhit() {
     int t = current_search_time();
     PonderSearch = false;
-    if(Iteration >= 2 &&
+    if(Iteration >= 3 &&
        (!InfiniteSearch && (StopOnPonderhit ||
                             t > AbsoluteMaxSearchTime ||
                             (RootMoveNumber == 1 &&