In non-PV IID don't call evaluate when in check

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index c1f90e119a24d82379eac5521bb950ca2732f4de..4481cfc727e436b8888825c94ec4bc99d261b21e 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -139,7 +139,7 @@ namespace {
 
   // Use internal iterative deepening?
   const bool UseIIDAtPVNodes = true;
-  const bool UseIIDAtNonPVNodes = false;
+  const bool UseIIDAtNonPVNodes = true;
 
   // Internal iterative deepening margin. At Non-PV moves, when
   // UseIIDAtNonPVNodes is true, we do an internal iterative deepening
@@ -1435,7 +1435,7 @@ namespace {
 
     // Go with internal iterative deepening if we don't have a TT move
     if (UseIIDAtNonPVNodes && ttMove == MOVE_NONE && depth >= 8*OnePly &&
-        evaluate(pos, ei, threadID) >= beta - IIDMargin)
+        !isCheck && evaluate(pos, ei, threadID) >= beta - IIDMargin)
     {
         search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID);
         ttMove = ss[ply].pv[ply];
@@ -1814,6 +1814,7 @@ namespace {
     bool useFutilityPruning =     sp->depth < SelectiveDepth
                               && !isCheck;
 
+    const int FutilityMoveCountMargin = 3 + (1 << (3 * int(sp->depth) / 8));
     const int FutilityValueMargin = 112 * bitScanReverse32(int(sp->depth) * int(sp->depth) / 2);
 
     while (    sp->bestValue < sp->beta
@@ -1842,31 +1843,30 @@ namespace {
           && !captureOrPromotion)
       {
           // Move count based pruning
-          if (   moveCount >= 2 + int(sp->depth)
+          if (   moveCount >= FutilityMoveCountMargin
               && ok_to_prune(pos, move, ss[sp->ply].threatMove)
               && sp->bestValue > value_mated_in(PLY_MAX))
               continue;
 
           // Value based pruning
-          if (sp->approximateEval < sp->beta)
+          if (sp->futilityValue == VALUE_NONE)
           {
-              if (sp->futilityValue == VALUE_NONE)
-              {
-                  EvalInfo ei;
-                  sp->futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin;
-              }
+              EvalInfo ei;
+              sp->futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin;
+          }
 
-              if (sp->futilityValue < sp->beta)
+          Value futilityValueScaled = sp->futilityValue - moveCount * IncrementalFutilityMargin;
+
+          if (futilityValueScaled < sp->beta)
+          {
+              if (futilityValueScaled > sp->bestValue) // Less then 1% of cases
               {
-                  if (sp->futilityValue > sp->bestValue) // Less then 1% of cases
-                  {
-                      lock_grab(&(sp->lock));
-                      if (sp->futilityValue > sp->bestValue)
-                          sp->bestValue = sp->futilityValue;
-                      lock_release(&(sp->lock));
-                  }
-                  continue;
+                  lock_grab(&(sp->lock));
+                  if (futilityValueScaled > sp->bestValue)
+                      sp->bestValue = futilityValueScaled;
+                  lock_release(&(sp->lock));
               }
+              continue;
           }
       }
 
@@ -2471,7 +2471,6 @@ namespace {
     assert(!pos.move_is_check(m));
     assert(!pos.move_is_capture_or_promotion(m));
     assert(!pos.move_is_passed_pawn_push(m));
-    assert(d >= OnePly);
 
     Square mfrom, mto, tfrom, tto;