Beta is never changed after an sp_search()

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 611b258329b680b5c7a07bacf466e3c6be7a55bf..11299121ba2435a4d1631df85616e22e779f7521 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -84,7 +84,7 @@ namespace {
     void wake_sleeping_threads();
     void put_threads_to_sleep();
     void idle_loop(int threadID, SplitPoint* waitSp);
-    bool split(const Position& pos, SearchStack* ss, int ply, Value* alpha, Value* beta, Value* bestValue,
+    bool split(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
                const Value futilityValue, Depth depth, int* moves, MovePicker* mp, int master, bool pvNode);
 
   private:
@@ -1210,7 +1210,7 @@ namespace {
           && TM.available_thread_exists(threadID)
           && !AbortSearch
           && !TM.thread_should_stop(threadID)
-          && TM.split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE,
+          && TM.split(pos, ss, ply, &alpha, beta, &bestValue, VALUE_NONE,
                       depth, &moveCount, &mp, threadID, true))
           break;
     }
@@ -1524,7 +1524,7 @@ namespace {
           && TM.available_thread_exists(threadID)
           && !AbortSearch
           && !TM.thread_should_stop(threadID)
-          && TM.split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, //FIXME: SMP & futilityValue
+          && TM.split(pos, ss, ply, NULL, beta, &bestValue, futilityValue, //FIXME: SMP & futilityValue
                       depth, &moveCount, &mp, threadID, false))
           break;
     }
@@ -1854,16 +1854,7 @@ namespace {
       // New best move?
       if (value > sp->bestValue) // Less then 2% of cases
       {
-          // Recursive locking, lock current split point and its ancestors to
-          // guarantee thread_should_stop() and sp_update_pv() are race free.
-          SplitPoint* spChain[MAX_THREADS * ACTIVE_SPLIT_POINTS_MAX];
-          int cnt = 0;
-          for (spChain[cnt] = sp; spChain[cnt]; )
-          {
-              lock_grab(&(spChain[cnt++]->lock));
-              spChain[cnt] = spChain[cnt - 1]->parent;
-          }
-
+          lock_grab(&(sp->lock));
           if (value > sp->bestValue && !TM.thread_should_stop(threadID))
           {
               sp->bestValue = value;
@@ -1873,10 +1864,7 @@ namespace {
                   sp_update_pv(sp->parentSstack, ss, sp->ply);
               }
           }
-
-          // Release locks in reverse order
-          while (cnt > 0)
-              lock_release(&(spChain[--cnt]->lock));
+          lock_release(&(sp->lock));
       }
     }
 
@@ -1975,16 +1963,7 @@ namespace {
       // New best move?
       if (value > sp->bestValue) // Less then 2% of cases
       {
-          // Recursive locking, lock current split point and its ancestors to
-          // guarantee thread_should_stop() and sp_update_pv() are race free.
-          SplitPoint* spChain[MAX_THREADS * ACTIVE_SPLIT_POINTS_MAX];
-          int cnt = 0;
-          for (spChain[cnt] = sp; spChain[cnt]; )
-          {
-              lock_grab(&(spChain[cnt++]->lock));
-              spChain[cnt] = spChain[cnt - 1]->parent;
-          }
-
+          lock_grab(&(sp->lock));
           if (value > sp->bestValue && !TM.thread_should_stop(threadID))
           {
               sp->bestValue = value;
@@ -2001,10 +1980,7 @@ namespace {
                       ss[sp->ply].mateKiller = move;
               }
           }
-
-          // Release locks in reverse order
-          while (cnt > 0)
-              lock_release(&(spChain[--cnt]->lock));
+          lock_release(&(sp->lock));
       }
     }
 
@@ -2684,7 +2660,7 @@ namespace {
     lock_init(&IOLock, NULL);
 
     // Initialize SplitPointStack locks
-    for (int i = 0; i < MAX_THREADS; i++)
+    for (i = 0; i < MAX_THREADS; i++)
         for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
         {
             SplitPointStack[i][j].parent = NULL;
@@ -2839,7 +2815,7 @@ namespace {
   // splitPoint->cpus becomes 0), split() returns true.
 
   bool ThreadsManager::split(const Position& p, SearchStack* sstck, int ply,
-             Value* alpha, Value* beta, Value* bestValue, const Value futilityValue,
+             Value* alpha, const Value beta, Value* bestValue, const Value futilityValue,
              Depth depth, int* moves, MovePicker* mp, int master, bool pvNode) {
 
     assert(p.is_ok());
@@ -2866,16 +2842,15 @@ namespace {
     }
 
     // Pick the next available split point object from the split point stack
-    splitPoint = SplitPointStack[master] + threads[master].activeSplitPoints;
-    threads[master].activeSplitPoints++;
+    splitPoint = &SplitPointStack[master][threads[master].activeSplitPoints];
 
     // Initialize the split point object
     splitPoint->parent = threads[master].splitPoint;
     splitPoint->stopRequest = false;
     splitPoint->ply = ply;
     splitPoint->depth = depth;
-    splitPoint->alpha = pvNode ? *alpha : (*beta - 1);
-    splitPoint->beta = *beta;
+    splitPoint->alpha = pvNode ? *alpha : beta - 1;
+    splitPoint->beta = beta;
     splitPoint->pvNode = pvNode;
     splitPoint->bestValue = *bestValue;
     splitPoint->futilityValue = futilityValue;
@@ -2889,6 +2864,7 @@ namespace {
         splitPoint->slaves[i] = 0;
 
     threads[master].splitPoint = splitPoint;
+    threads[master].activeSplitPoints++;
 
     // If we are here it means we are not available
     assert(threads[master].state != THREAD_AVAILABLE);
@@ -2935,7 +2911,6 @@ namespace {
     if (pvNode)
         *alpha = splitPoint->alpha;
 
-    *beta = splitPoint->beta;
     *bestValue = splitPoint->bestValue;
     threads[master].activeSplitPoints--;
     threads[master].splitPoint = splitPoint->parent;