From: Marco Costalba <mcostalba@gmail.com>
Date: Sun, 10 Jan 2010 11:38:59 +0000 (+0100)
Subject: Fix sending of best move during an infinite search
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=55745f410547f22b1edce873b38cc3ce5f3ace5f;hp=968c3de8e0acd46a8b55225dda1ed607ce24f380

Fix sending of best move during an infinite search

According to UCI standard once engine receives 'go infinite'
command it should search until the "stop" command and do not exit
the search without being told so, even if PLY_MAX has been reached.

Patch is quite invasive because it cleanups some hacks used
by fixed depth and fixed nodes modes, mainly during benchmarks.

Bug found by Pascal Georges.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---

diff --git a/src/benchmark.cpp b/src/benchmark.cpp
index d7972649..3abcda62 100644
--- a/src/benchmark.cpp
+++ b/src/benchmark.cpp
@@ -155,7 +155,7 @@ void benchmark(const string& commandLine) {
       cerr << "\nBench position: " << cnt << '/' << positions.size() << endl << endl;
       if (limitType == "perft")
           totalNodes += perft(pos, maxDepth * OnePly);
-      else if (!think(pos, true, false, 0, dummy, dummy, 0, maxDepth, maxNodes, secsPerPos, moves))
+      else if (!think(pos, false, false, 0, dummy, dummy, 0, maxDepth, maxNodes, secsPerPos, moves))
           break;
       totalNodes += nodes_searched();
   }
diff --git a/src/search.cpp b/src/search.cpp
index 4a8dd17f..3dbcb526 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -231,7 +231,7 @@ namespace {
   int SearchStartTime;
   int MaxNodes, MaxDepth;
   int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
-  bool InfiniteSearch, PonderSearch, StopOnPonderhit;
+  bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
   bool AbortSearch, Quit;
   bool FailHigh, FailLow, Problem;
 
@@ -373,8 +373,20 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
            int time[], int increment[], int movesToGo, int maxDepth,
            int maxNodes, int maxTime, Move searchMoves[]) {
 
-  // Look for a book move
-  if (!infinite && !ponder && get_option_value_bool("OwnBook"))
+  // Initialize global search variables
+  Idle = StopOnPonderhit = AbortSearch = Quit = false;
+  FailHigh = FailLow = Problem = false;
+  NodesSincePoll = 0;
+  SearchStartTime = get_system_time();
+  ExactMaxTime = maxTime;
+  MaxDepth = maxDepth;
+  MaxNodes = maxNodes;
+  InfiniteSearch = infinite;
+  PonderSearch = ponder;
+  UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch;
+
+  // Look for a book move, only during games, not tests
+  if (UseTimeManagement && !ponder && get_option_value_bool("OwnBook"))
   {
       Move bookMove;
       if (get_option_value_string("Book File") != OpeningBook.file_name())
@@ -388,15 +400,6 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
       }
   }
 
-  // Initialize global search variables
-  Idle = StopOnPonderhit = AbortSearch = Quit = false;
-  FailHigh = FailLow = Problem = false;
-  SearchStartTime = get_system_time();
-  ExactMaxTime = maxTime;
-  NodesSincePoll = 0;
-  InfiniteSearch = infinite;
-  PonderSearch = ponder;
-
   for (int i = 0; i < THREAD_MAX; i++)
   {
       Threads[i].nodes = 0ULL;
@@ -464,51 +467,45 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
   // Set thinking time
   int myTime = time[side_to_move];
   int myIncrement = increment[side_to_move];
-
-  if (!movesToGo) // Sudden death time control
+  if (UseTimeManagement)
   {
-      if (myIncrement)
-      {
-          MaxSearchTime = myTime / 30 + myIncrement;
-          AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
-      }
-      else // Blitz game without increment
+      if (!movesToGo) // Sudden death time control
       {
-          MaxSearchTime = myTime / 30;
-          AbsoluteMaxSearchTime = myTime / 8;
+          if (myIncrement)
+          {
+              MaxSearchTime = myTime / 30 + myIncrement;
+              AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
+          }
+          else // Blitz game without increment
+          {
+              MaxSearchTime = myTime / 30;
+              AbsoluteMaxSearchTime = myTime / 8;
+          }
       }
-  }
-  else // (x moves) / (y minutes)
-  {
-      if (movesToGo == 1)
+      else // (x moves) / (y minutes)
       {
-          MaxSearchTime = myTime / 2;
-          AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
+          if (movesToGo == 1)
+          {
+              MaxSearchTime = myTime / 2;
+              AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
+          }
+          else
+          {
+              MaxSearchTime = myTime / Min(movesToGo, 20);
+              AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
+          }
       }
-      else
+
+      if (PonderingEnabled)
       {
-          MaxSearchTime = myTime / Min(movesToGo, 20);
-          AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
+          MaxSearchTime += MaxSearchTime / 4;
+          MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime);
       }
   }
 
-  if (PonderingEnabled)
-  {
-      MaxSearchTime += MaxSearchTime / 4;
-      MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime);
-  }
-
-  // Fixed depth or fixed number of nodes?
-  MaxDepth = maxDepth;
-  if (MaxDepth)
-      InfiniteSearch = true; // HACK
-
-  MaxNodes = maxNodes;
+  // Set best NodesBetweenPolls interval
   if (MaxNodes)
-  {
       NodesBetweenPolls = Min(MaxNodes, 30000);
-      InfiniteSearch = true; // HACK
-  }
   else if (myTime && myTime < 1000)
       NodesBetweenPolls = 1000;
   else if (myTime && myTime < 5000)
@@ -791,7 +788,7 @@ namespace {
 
         Problem = false;
 
-        if (!InfiniteSearch)
+        if (UseTimeManagement)
         {
             // Time to stop?
             bool stopSearch = false;
@@ -845,9 +842,9 @@ namespace {
 
     rml.sort();
 
-    // If we are pondering, we shouldn't print the best move before we
-    // are told to do so
-    if (PonderSearch)
+    // If we are pondering or in infinite search, we shouldn't print the
+    // best move before we are told to do so.
+    if (PonderSearch || InfiniteSearch)
         wait_for_stop_or_ponderhit();
     else
         // Print final search statistics
@@ -2680,7 +2677,7 @@ namespace {
                      || stillAtFirstMove //FIXME: We are not checking any problem flags, BUG?
                      || noProblemFound;
 
-    if (   (Iteration >= 3 && !InfiniteSearch && noMoreTime)
+    if (   (Iteration >= 3 && UseTimeManagement && noMoreTime)
         || (ExactMaxTime && t >= ExactMaxTime)
         || (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes))
         AbortSearch = true;
@@ -2710,7 +2707,7 @@ namespace {
                      || stillAtFirstMove
                      || noProblemFound;
 
-    if (Iteration >= 3 && !InfiniteSearch && (noMoreTime || StopOnPonderhit))
+    if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit))
         AbortSearch = true;
   }