#include "lock.h"
#include "san.h"
#include "search.h"
+#include "timeman.h"
#include "thread.h"
#include "tt.h"
#include "ucioption.h"
template <bool Fake>
void split(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
- Depth depth, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode);
+ Depth depth, Move threatMove, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode);
private:
friend void poll();
Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2];
// Minimum depth for use of singular extension
- const Depth SingularExtensionDepth[2] = { 8 * OnePly /* non-PV */, 6 * OnePly /* PV */};
+ const Depth SingularExtensionDepth[2] = { 7 * OnePly /* non-PV */, 6 * OnePly /* PV */};
// If the TT move is at least SingularExtensionMargin better then the
// remaining ones we will extend it.
int MultiPV;
// Time managment variables
- int SearchStartTime, MaxNodes, MaxDepth, MaxSearchTime;
- int AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
+ int SearchStartTime, MaxNodes, MaxDepth, OptimumSearchTime;
+ int MaximumSearchTime, ExtraSearchTime, ExactMaxTime;
bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
void wait_for_stop_or_ponderhit();
void init_ss_array(SearchStack* ss, int size);
void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value);
+ void insert_pv_in_tt(const Position& pos, Move pv[]);
+ void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]);
#if !defined(_MSC_VER)
void *init_thread(void *threadID);
}
-// SearchStack::init() initializes a search stack entry.
-// Called at the beginning of search() when starting to examine a new node.
-void SearchStack::init() {
-
- currentMove = threatMove = bestMove = MOVE_NONE;
-}
-
-// SearchStack::initKillers() initializes killers for a search stack entry
-void SearchStack::initKillers() {
-
- killers[0] = killers[1] = mateKiller = MOVE_NONE;
-}
-
-
/// perft() is our utility to verify move generation is bug free. All the legal
/// moves up to given depth are generated and counted and the sum returned.
// Initialize global search variables
StopOnPonderhit = AbortSearch = Quit = AspirationFailLow = false;
- MaxSearchTime = AbsoluteMaxSearchTime = ExtraSearchTime = 0;
+ OptimumSearchTime = MaximumSearchTime = ExtraSearchTime = 0;
NodesSincePoll = 0;
TM.resetNodeCounters();
SearchStartTime = get_system_time();
int myIncrement = increment[pos.side_to_move()];
if (UseTimeManagement)
{
- if (!movesToGo) // Sudden death time control
- {
- 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)
- {
- MaxSearchTime = myTime / 2;
- AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
- }
- else
- {
- MaxSearchTime = myTime / Min(movesToGo, 20);
- AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
- }
- }
+ get_search_times(myTime, myIncrement, movesToGo, pos.startpos_ply_counter(),
+ &OptimumSearchTime, &MaximumSearchTime);
if (get_option_value_bool("Ponder"))
{
- MaxSearchTime += MaxSearchTime / 4;
- MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime);
+ OptimumSearchTime += OptimumSearchTime / 4;
+ OptimumSearchTime = Min(OptimumSearchTime, MaximumSearchTime);
}
}
// Write PV to transposition table, in case the relevant entries have
// been overwritten during the search.
- TT.insert_pv(p, pv);
+ insert_pv_in_tt(p, pv);
if (AbortSearch)
break; // Value cannot be trusted. Break out immediately!
if ( Iteration >= 8
&& EasyMove == pv[0]
&& ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
- && current_search_time() > MaxSearchTime / 16)
+ && current_search_time() > OptimumSearchTime / 16)
||( rml.get_move_cumulative_nodes(0) > (nodes * 98) / 100
- && current_search_time() > MaxSearchTime / 32)))
+ && current_search_time() > OptimumSearchTime / 32)))
stopSearch = true;
// Add some extra time if the best move has changed during the last two iterations
if (Iteration > 5 && Iteration <= 50)
- ExtraSearchTime = BestMoveChangesByIteration[Iteration] * (MaxSearchTime / 2)
- + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
+ ExtraSearchTime = BestMoveChangesByIteration[Iteration] * (OptimumSearchTime / 2)
+ + BestMoveChangesByIteration[Iteration-1] * (OptimumSearchTime / 3);
// 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.
- if (current_search_time() > ((MaxSearchTime + ExtraSearchTime) * 80) / 128)
+ if (current_search_time() > ((OptimumSearchTime + ExtraSearchTime) * 80) / 128)
stopSearch = true;
if (stopSearch)
beta = *betaPtr;
isCheck = pos.is_check();
- // Step 1. Initialize node and poll (omitted at root, init_ss_array() has already initialized root node)
+ // Step 1. Initialize node (polling is omitted at root)
+ ss->currentMove = ss->bestMove = MOVE_NONE;
+
// Step 2. Check for aborted search (omitted at root)
// Step 3. Mate distance pruning (omitted at root)
// Step 4. Transposition table lookup (omitted at root)
// the score before research in case we run out of time while researching.
rml.set_move_score(i, value);
ss->bestMove = move;
- TT.extract_pv(pos, move, pv, PLY_MAX);
+ extract_pv_from_tt(pos, move, pv);
rml.set_move_pv(i, pv);
// Print information to the standard output
// Update PV
rml.set_move_score(i, value);
ss->bestMove = move;
- TT.extract_pv(pos, move, pv, PLY_MAX);
+ extract_pv_from_tt(pos, move, pv);
rml.set_move_pv(i, pv);
if (MultiPV == 1)
Move movesSearched[256];
EvalInfo ei;
StateInfo st;
- const TTEntry* tte;
+ const TTEntry *tte, *ttx;
Key posKey;
- Move ttMove, move, excludedMove;
+ Move ttMove, move, excludedMove, threatMove;
Depth ext, newDepth;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityValueScaled; // Non-PV specific
// Step 1. Initialize node and poll. Polling can abort search
TM.incrementNodeCounter(threadID);
- ss->init();
- (ss+2)->initKillers();
+ ss->currentMove = ss->bestMove = threatMove = MOVE_NONE;
+ (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE;
if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
{
// Refresh tte entry to avoid aging
TT.store(posKey, tte->value(), tte->type(), tte->depth(), ttMove, tte->static_value(), tte->king_danger());
- ss->currentMove = ttMove; // Can be MOVE_NONE
+ ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
isCheck = pos.is_check();
if (!isCheck)
{
- if (tte && tte->static_value() != VALUE_NONE)
+ if (tte)
{
+ assert(tte->static_value() != VALUE_NONE);
ss->eval = tte->static_value();
ei.kingDanger[pos.side_to_move()] = tte->king_danger();
}
else
+ {
ss->eval = evaluate(pos, ei);
+ TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+ }
refinedValue = refine_eval(tte, ss->eval, ply); // Enhance accuracy with TT value if possible
update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
&& !value_is_mate(beta)
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
- // Pass ss->eval to qsearch() and avoid an evaluate call
- if (!tte || tte->static_value() == VALUE_NONE)
- TT.store(posKey, ss->eval, VALUE_TYPE_EXACT, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
-
Value rbeta = beta - razor_margin(depth);
Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, Depth(0), ply);
if (v < rbeta)
if (nullValue == value_mated_in(ply + 2))
mateThreat = true;
- ss->threatMove = (ss+1)->currentMove;
+ threatMove = (ss+1)->bestMove;
if ( depth < ThreatDepth
&& (ss-1)->reduction
- && connected_moves(pos, (ss-1)->currentMove, ss->threatMove))
+ && connected_moves(pos, (ss-1)->currentMove, threatMove))
return beta - 1;
}
}
&& move == tte->move()
&& ext < OnePly)
{
+ // Avoid to do an expensive singular extension search on nodes where
+ // such search have already been done in the past, so assume the last
+ // singular extension search result is still valid.
+ if ( !PvNode
+ && depth < SingularExtensionDepth[PvNode] + 5 * OnePly
+ && ((ttx = TT.retrieve(pos.get_exclusion_key())) != NULL))
+ {
+ if (is_upper_bound(ttx->type()))
+ ext = OnePly;
+
+ singularExtensionNode = false;
+ }
+
Value ttValue = value_from_tt(tte->value(), ply);
- if (abs(ttValue) < VALUE_KNOWN_WIN)
+ if (singularExtensionNode && abs(ttValue) < VALUE_KNOWN_WIN)
{
Value b = ttValue - SingularExtensionMargin;
ss->excludedMove = move;
{
// Move count based pruning
if ( moveCount >= futility_move_count(depth)
- && !(ss->threatMove && connected_threat(pos, move, ss->threatMove))
+ && !(threatMove && connected_threat(pos, move, threatMove))
&& bestValue > value_mated_in(PLY_MAX))
continue;
&& !TM.thread_should_stop(threadID)
&& Iteration <= 99)
TM.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
- mateThreat, &moveCount, &mp, PvNode);
+ threatMove, mateThreat, &moveCount, &mp, PvNode);
}
// Step 19. Check for mate and stalemate
if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
{
- ss->currentMove = ttMove; // Can be MOVE_NONE
+ ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
}
else
{
- if (tte && tte->static_value() != VALUE_NONE)
+ if (tte)
{
+ assert(tte->static_value() != VALUE_NONE);
ei.kingDanger[pos.side_to_move()] = tte->king_danger();
bestValue = tte->static_value();
}
if (bestValue >= beta)
{
if (!tte)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
return bestValue;
}
{
// Move count based pruning
if ( moveCount >= futility_move_count(sp->depth)
- && !(ss->threatMove && connected_threat(pos, move, ss->threatMove))
+ && !(sp->threatMove && connected_threat(pos, move, sp->threatMove))
&& sp->bestValue > value_mated_in(PLY_MAX))
{
lock_grab(&(sp->lock));
bool stillAtFirstMove = FirstRootMove
&& !AspirationFailLow
- && t > MaxSearchTime + ExtraSearchTime;
+ && t > OptimumSearchTime + ExtraSearchTime;
- bool noMoreTime = t > AbsoluteMaxSearchTime
+ bool noMoreTime = t > MaximumSearchTime
|| stillAtFirstMove;
if ( (Iteration >= 3 && UseTimeManagement && noMoreTime)
bool stillAtFirstMove = FirstRootMove
&& !AspirationFailLow
- && t > MaxSearchTime + ExtraSearchTime;
+ && t > OptimumSearchTime + ExtraSearchTime;
- bool noMoreTime = t > AbsoluteMaxSearchTime
+ bool noMoreTime = t > MaximumSearchTime
|| stillAtFirstMove;
if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit))
ss->reduction = Depth(0);
if (i < 3)
- {
- ss->init();
- ss->initKillers();
- }
+ ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE;
}
}
}
+ // insert_pv_in_tt() is called at the end of a search iteration, and inserts
+ // the PV back into the TT. This makes sure the old PV moves are searched
+ // first, even if the old TT entries have been overwritten.
+
+ void insert_pv_in_tt(const Position& pos, Move pv[]) {
+
+ StateInfo st;
+ TTEntry* tte;
+ Position p(pos, pos.thread());
+ EvalInfo ei;
+ Value v;
+
+ for (int i = 0; pv[i] != MOVE_NONE; i++)
+ {
+ tte = TT.retrieve(p.get_key());
+ if (!tte || tte->move() != pv[i])
+ {
+ v = (p.is_check() ? VALUE_NONE : evaluate(p, ei));
+ TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, ei.kingDanger[pos.side_to_move()]);
+ }
+ p.do_move(pv[i], st);
+ }
+ }
+
+
+ // extract_pv_from_tt() builds a PV by adding moves from the transposition table.
+ // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
+ // allow to always have a ponder move even when we fail high at root and also a
+ // long PV to print that is important for position analysis.
+
+ void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]) {
+
+ StateInfo st;
+ TTEntry* tte;
+ Position p(pos, pos.thread());
+ int ply = 0;
+
+ assert(bestMove != MOVE_NONE);
+
+ pv[ply] = bestMove;
+ p.do_move(pv[ply++], st);
+
+ while ( (tte = TT.retrieve(p.get_key())) != NULL
+ && tte->move() != MOVE_NONE
+ && move_is_legal(p, tte->move())
+ && ply < PLY_MAX
+ && (!p.is_draw() || ply < 2))
+ {
+ pv[ply] = tte->move();
+ p.do_move(pv[ply++], st);
+ }
+ pv[ply] = MOVE_NONE;
+ }
+
+
// init_thread() is the function which is called when a new thread is
// launched. It simply calls the idle_loop() function with the supplied
// threadID. There are two versions of this function; one for POSIX
#endif
// Initialize global locks
- lock_init(&MPLock, NULL);
- lock_init(&WaitLock, NULL);
+ lock_init(&MPLock);
+ lock_init(&WaitLock);
#if !defined(_MSC_VER)
pthread_cond_init(&WaitCond, NULL);
// Initialize splitPoints[] locks
for (i = 0; i < MAX_THREADS; i++)
for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
- lock_init(&(threads[i].splitPoints[j].lock), NULL);
+ lock_init(&(threads[i].splitPoints[j].lock));
// Will be set just before program exits to properly end the threads
AllThreadsShouldExit = false;
template <bool Fake>
void ThreadsManager::split(const Position& p, SearchStack* ss, int ply, Value* alpha,
- const Value beta, Value* bestValue, Depth depth, bool mateThreat,
- int* moveCount, MovePicker* mp, bool pvNode) {
+ const Value beta, Value* bestValue, Depth depth, Move threatMove,
+ bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode) {
assert(p.is_ok());
assert(ply > 0 && ply < PLY_MAX);
assert(*bestValue >= -VALUE_INFINITE);
splitPoint.stopRequest = false;
splitPoint.ply = ply;
splitPoint.depth = depth;
+ splitPoint.threatMove = threatMove;
splitPoint.mateThreat = mateThreat;
splitPoint.alpha = *alpha;
splitPoint.beta = beta;
StateInfo st;
bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
+ // Initialize search stack
+ init_ss_array(ss, PLY_MAX_PLUS_2);
+ ss[0].currentMove = ss[0].bestMove = MOVE_NONE;
+ ss[0].eval = VALUE_NONE;
+
// Generate all legal moves
MoveStack* last = generate_moves(pos, mlist);
continue;
// Find a quick score for the move
- init_ss_array(ss, PLY_MAX_PLUS_2);
- ss[0].eval = VALUE_NONE;
- ss[0].currentMove = cur->move;
pos.do_move(cur->move, st);
+ ss[0].currentMove = cur->move;
moves[count].move = cur->move;
moves[count].score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1);
moves[count].pv[0] = cur->move;
projects / stockfish / blobdiff