////
#include <cassert>
+#include <cmath>
#include <cstring>
#include <fstream>
#include <iostream>
/// Types
- // IterationInfoType stores search results for each iteration
- //
- // Because we use relatively small (dynamic) aspiration window,
- // there happens many fail highs and fail lows in root. And
- // because we don't do researches in those cases, "value" stored
- // here is not necessarily exact. Instead in case of fail high/low
- // we guess what the right value might be and store our guess
- // as a "speculated value" and then move on. Speculated values are
- // used just to calculate aspiration window width, so also if are
- // not exact is not big a problem.
-
- struct IterationInfoType {
-
- IterationInfoType(Value v = Value(0), Value sv = Value(0))
- : value(v), speculatedValue(sv) {}
-
- Value value, speculatedValue;
- };
-
-
// The BetaCounterType class is used to order moves at ply one.
// Apart for the first one that has its score, following moves
// normally have score -VALUE_INFINITE, so are ordered according
// better than the second best move.
const Value EasyMoveMargin = Value(0x200);
- // Problem margin. If the score of the first move at iteration N+1 has
- // dropped by more than this since iteration N, the boolean variable
- // "Problem" is set to true, which will make the program spend some extra
- // time looking for a better move.
- const Value ProblemMargin = Value(0x28);
-
- // No problem margin. If the boolean "Problem" is true, and a new move
- // is found at the root which is less than NoProblemMargin worse than the
- // best move from the previous iteration, Problem is set back to false.
- const Value NoProblemMargin = Value(0x14);
-
// Null move margin. A null move search will not be done if the static
// evaluation of the position is more than NullMoveMargin below beta.
const Value NullMoveMargin = Value(0x200);
// and near frontier nodes.
const Value FutilityMarginQS = Value(0x80);
+ Value FutilityMargins[2 * PLY_MAX_PLUS_2]; // Initialized at startup.
+
// Each move futility margin is decreased
const Value IncrementalFutilityMargin = Value(0x8);
/// Variables initialized by UCI options
- // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV nodes
- int LMRPVMoves, LMRNonPVMoves;
-
// Depth limit for use of dynamic threat detection
Depth ThreatDepth;
BetaCounterType BetaCounter;
// Scores and number of times the best move changed for each iteration
- IterationInfoType IterationInfo[PLY_MAX_PLUS_2];
+ Value ValueByIteration[PLY_MAX_PLUS_2];
int BestMoveChangesByIteration[PLY_MAX_PLUS_2];
+ // Search window management
+ int AspirationDelta;
+
// MultiPV mode
int MultiPV;
int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
bool AbortSearch, Quit;
- bool FailHigh, FailLow, Problem;
+ bool AspirationFailLow;
// Show current line?
bool ShowCurrentLine;
bool UseLogFile;
std::ofstream LogFile;
+ // Reduction lookup tables and their getter functions
+ // Initialized at startup
+ int8_t PVReductionMatrix[64][64]; // [depth][moveNumber]
+ int8_t NonPVReductionMatrix[64][64]; // [depth][moveNumber]
+
+ inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; }
+ inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; }
+
// MP related variables
int ActiveThreads = 1;
Depth MinimumSplitDepth;
// History table
History H;
-
/// Functions
Value id_loop(const Position& pos, Move searchMoves[]);
- Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value alpha, Value beta);
+ Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta);
Value search_pv(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, int ply, bool allowNullmove, int threadID, Move excludedMove = MOVE_NONE);
Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
Value refine_eval(const TTEntry* tte, Value defaultEval, int ply);
void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount);
void update_killers(Move m, SearchStack& ss);
+ void update_gains(const Position& pos, Move move, Value before, Value after);
- bool fail_high_ply_1();
int current_search_time();
int nps();
void poll();
//// Functions
////
-//FIXME: HACK
-static double lnArray[512];
-
-inline double ln(int i)
-{
- return lnArray[i];
-}
/// 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
Idle = StopOnPonderhit = AbortSearch = Quit = false;
- FailHigh = FailLow = Problem = false;
+ AspirationFailLow = false;
NodesSincePoll = 0;
SearchStartTime = get_system_time();
ExactMaxTime = maxTime;
UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch;
// Look for a book move, only during games, not tests
- if (UseTimeManagement && !ponder && get_option_value_bool("OwnBook"))
+ if (UseTimeManagement && get_option_value_bool("OwnBook"))
{
Move bookMove;
if (get_option_value_string("Book File") != OpeningBook.file_name())
bookMove = OpeningBook.get_move(pos);
if (bookMove != MOVE_NONE)
{
+ if (PonderSearch)
+ wait_for_stop_or_ponderhit();
+
cout << "bestmove " << bookMove << endl;
return true;
}
for (int i = 0; i < THREAD_MAX; i++)
{
Threads[i].nodes = 0ULL;
- Threads[i].failHighPly1 = false;
}
if (button_was_pressed("New Game"))
MateThreatExtension[1] = Depth(get_option_value_int("Mate Threat Extension (PV nodes)"));
MateThreatExtension[0] = Depth(get_option_value_int("Mate Threat Extension (non-PV nodes)"));
- LMRPVMoves = get_option_value_int("Full Depth Moves (PV nodes)") + 1;
- LMRNonPVMoves = get_option_value_int("Full Depth Moves (non-PV nodes)") + 1;
ThreatDepth = get_option_value_int("Threat Depth") * OnePly;
Chess960 = get_option_value_bool("UCI_Chess960");
{
ActiveThreads = newActiveThreads;
init_eval(ActiveThreads);
+ // HACK: init_eval() destroys the static castleRightsMask[] array in the
+ // Position class. The below line repairs the damage.
+ Position p(pos.to_fen());
+ assert(pos.is_ok());
}
// Wake up sleeping threads
// We're ready to start thinking. Call the iterative deepening loop function
Value v = id_loop(pos, searchMoves);
-
if (UseLSNFiltering)
{
// Step 1. If this is sudden death game and our position is hopeless,
/// and initializes the split point stack and the global locks and condition
/// objects.
-#include <cmath> //FIXME: HACK
-
void init_threads() {
- // FIXME: HACK!!
- for (int i = 0; i < 512; i++)
- lnArray[i] = log(double(i));
-
volatile int i;
+ bool ok;
#if !defined(_MSC_VER)
pthread_t pthread[1];
#endif
+ // Init our reduction lookup tables
+ for (i = 1; i < 64; i++) // i == depth
+ for (int j = 1; j < 64; j++) // j == moveNumber
+ {
+ double pvRed = 0.5 + log(double(i)) * log(double(j)) / 6.0;
+ double nonPVRed = 0.5 + log(double(i)) * log(double(j)) / 3.0;
+ PVReductionMatrix[i][j] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0);
+ NonPVReductionMatrix[i][j] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0);
+ }
+
+ // Init futility margins array
+ FutilityMargins[0] = FutilityMargins[1] = Value(0);
+
+ for (i = 2; i < 2 * PLY_MAX_PLUS_2; i++)
+ {
+ FutilityMargins[i] = Value(112 * bitScanReverse32(i * i / 2)); // FIXME: test using log instead of BSR
+ }
+
for (i = 0; i < THREAD_MAX; i++)
Threads[i].activeSplitPoints = 0;
for (i = 1; i < THREAD_MAX; i++)
{
#if !defined(_MSC_VER)
- pthread_create(pthread, NULL, init_thread, (void*)(&i));
+ ok = (pthread_create(pthread, NULL, init_thread, (void*)(&i)) == 0);
#else
DWORD iID[1];
- CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID);
+ ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID) != NULL);
#endif
+ if (!ok)
+ {
+ cout << "Failed to create thread number " << i << endl;
+ Application::exit_with_failure();
+ }
+
// Wait until the thread has finished launching
while (!Threads[i].running);
}
currentMove = threatMove = MOVE_NONE;
reduction = Depth(0);
eval = VALUE_NONE;
+ evalInfo = NULL;
}
void SearchStack::initKillers() {
// searchMoves are verified, copied, scored and sorted
RootMoveList rml(p, searchMoves);
+ // Handle special case of searching on a mate/stale position
if (rml.move_count() == 0)
{
if (PonderSearch)
TT.new_search();
H.clear();
init_ss_array(ss);
- IterationInfo[1] = IterationInfoType(rml.get_move_score(0), rml.get_move_score(0));
+ ValueByIteration[1] = rml.get_move_score(0);
Iteration = 1;
// Is one move significantly better than others after initial scoring ?
// Calculate dynamic search window based on previous iterations
Value alpha, beta;
- if (MultiPV == 1 && Iteration >= 6 && abs(IterationInfo[Iteration - 1].value) < VALUE_KNOWN_WIN)
+ if (MultiPV == 1 && Iteration >= 6 && abs(ValueByIteration[Iteration - 1]) < VALUE_KNOWN_WIN)
{
- int prevDelta1 = IterationInfo[Iteration - 1].speculatedValue - IterationInfo[Iteration - 2].speculatedValue;
- int prevDelta2 = IterationInfo[Iteration - 2].speculatedValue - IterationInfo[Iteration - 3].speculatedValue;
+ int prevDelta1 = ValueByIteration[Iteration - 1] - ValueByIteration[Iteration - 2];
+ int prevDelta2 = ValueByIteration[Iteration - 2] - ValueByIteration[Iteration - 3];
- int delta = Max(2 * abs(prevDelta1) + abs(prevDelta2), ProblemMargin);
+ AspirationDelta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16);
+ AspirationDelta = (AspirationDelta + 7) / 8 * 8; // Round to match grainSize
- alpha = Max(IterationInfo[Iteration - 1].value - delta, -VALUE_INFINITE);
- beta = Min(IterationInfo[Iteration - 1].value + delta, VALUE_INFINITE);
+ alpha = Max(ValueByIteration[Iteration - 1] - AspirationDelta, -VALUE_INFINITE);
+ beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE);
}
else
{
break; // Value cannot be trusted. Break out immediately!
//Save info about search result
- Value speculatedValue;
- bool fHigh = false;
- bool fLow = false;
- Value delta = value - IterationInfo[Iteration - 1].value;
-
- if (value >= beta)
- {
- assert(delta > 0);
-
- fHigh = true;
- speculatedValue = value + delta;
- BestMoveChangesByIteration[Iteration] += 2; // Allocate more time
- }
- else if (value <= alpha)
- {
- assert(value == alpha);
- assert(delta < 0);
-
- fLow = true;
- speculatedValue = value + delta;
- BestMoveChangesByIteration[Iteration] += 3; // Allocate more time
- } else
- speculatedValue = value;
-
- speculatedValue = Min(Max(speculatedValue, -VALUE_INFINITE), VALUE_INFINITE);
- IterationInfo[Iteration] = IterationInfoType(value, speculatedValue);
+ ValueByIteration[Iteration] = value;
// Drop the easy move if it differs from the new best move
if (ss[0].pv[0] != EasyMove)
EasyMove = MOVE_NONE;
- Problem = false;
-
if (UseTimeManagement)
{
// Time to stop?
// Stop search early when the last two iterations returned a mate score
if ( Iteration >= 6
- && abs(IterationInfo[Iteration].value) >= abs(VALUE_MATE) - 100
- && abs(IterationInfo[Iteration-1].value) >= abs(VALUE_MATE) - 100)
+ && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100
+ && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100)
stopSearch = true;
// Stop search early if one move seems to be much better than the rest
int64_t nodes = nodes_searched();
if ( Iteration >= 8
- && !fLow
- && !fHigh
&& EasyMove == ss[0].pv[0]
&& ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
&& current_search_time() > MaxSearchTime / 16)
// similar to search_pv except that it uses a different move ordering
// scheme and prints some information to the standard output.
- Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value alpha, Value beta) {
+ Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta) {
- Value oldAlpha = alpha;
+ int64_t nodes;
+ Move move;
+ StateInfo st;
+ Depth depth, ext, newDepth;
Value value;
CheckInfo ci(pos);
+ int researchCount = 0;
+ bool moveIsCheck, captureOrPromotion, dangerous;
+ Value alpha = oldAlpha;
+ bool isCheck = pos.is_check();
+
+ // Evaluate the position statically
+ EvalInfo ei;
+ ss[0].eval = !isCheck ? evaluate(pos, ei, 0) : VALUE_NONE;
- // Loop through all the moves in the root move list
- for (int i = 0; i < rml.move_count() && !AbortSearch; i++)
+ while (1) // Fail low loop
{
- if (alpha >= beta)
- {
- // We failed high, invalidate and skip next moves, leave node-counters
- // and beta-counters as they are and quickly return, we will try to do
- // a research at the next iteration with a bigger aspiration window.
- rml.set_move_score(i, -VALUE_INFINITE);
- continue;
- }
- int64_t nodes;
- Move move;
- StateInfo st;
- Depth depth, ext, newDepth;
- RootMoveNumber = i + 1;
- FailHigh = false;
+ // Loop through all the moves in the root move list
+ for (int i = 0; i < rml.move_count() && !AbortSearch; i++)
+ {
+ if (alpha >= beta)
+ {
+ // We failed high, invalidate and skip next moves, leave node-counters
+ // and beta-counters as they are and quickly return, we will try to do
+ // a research at the next iteration with a bigger aspiration window.
+ rml.set_move_score(i, -VALUE_INFINITE);
+ continue;
+ }
- // Save the current node count before the move is searched
- nodes = nodes_searched();
+ RootMoveNumber = i + 1;
- // Reset beta cut-off counters
- BetaCounter.clear();
+ // Save the current node count before the move is searched
+ nodes = nodes_searched();
- // Pick the next root move, and print the move and the move number to
- // the standard output.
- move = ss[0].currentMove = rml.get_move(i);
+ // Reset beta cut-off counters
+ BetaCounter.clear();
- if (current_search_time() >= 1000)
- cout << "info currmove " << move
- << " currmovenumber " << RootMoveNumber << endl;
+ // Pick the next root move, and print the move and the move number to
+ // the standard output.
+ move = ss[0].currentMove = rml.get_move(i);
- // Decide search depth for this move
- bool moveIsCheck = pos.move_is_check(move);
- bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
- bool dangerous;
- depth = (Iteration - 2) * OnePly + InitialDepth;
- ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
- newDepth = depth + ext;
+ if (current_search_time() >= 1000)
+ cout << "info currmove " << move
+ << " currmovenumber " << RootMoveNumber << endl;
- // Make the move, and search it
- pos.do_move(move, st, ci, moveIsCheck);
+ // Decide search depth for this move
+ moveIsCheck = pos.move_is_check(move);
+ captureOrPromotion = pos.move_is_capture_or_promotion(move);
+ depth = (Iteration - 2) * OnePly + InitialDepth;
+ ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
+ newDepth = depth + ext;
- if (i < MultiPV)
- {
- // Aspiration window is disabled in multi-pv case
- if (MultiPV > 1)
- alpha = -VALUE_INFINITE;
+ value = - VALUE_INFINITE;
- value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
+ while (1) // Fail high loop
+ {
- // If the value has dropped a lot compared to the last iteration,
- // set the boolean variable Problem to true. This variable is used
- // for time managment: When Problem is true, we try to complete the
- // current iteration before playing a move.
- Problem = ( Iteration >= 2
- && value <= IterationInfo[Iteration - 1].value - ProblemMargin);
+ // Make the move, and search it
+ pos.do_move(move, st, ci, moveIsCheck);
- if (Problem && StopOnPonderhit)
- StopOnPonderhit = false;
- }
- else
- {
- // Try to reduce non-pv search depth by one ply if move seems not problematic,
- // if the move fails high will be re-searched at full depth.
- if ( depth >= 3*OnePly // FIXME was newDepth
- && !dangerous
- && !captureOrPromotion
- && !move_is_castle(move))
- {
- double red = 0.5 + ln(RootMoveNumber - MultiPV + 1) * ln(depth / 2) / 6.0;
- if (red >= 1.0)
+ if (i < MultiPV || value > alpha)
{
- ss[0].reduction = Depth(int(floor(red * int(OnePly))));
- value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0);
+ // Aspiration window is disabled in multi-pv case
+ if (MultiPV > 1)
+ alpha = -VALUE_INFINITE;
+
+ value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
}
else
- value = alpha + 1; // Just to trigger next condition
- } else
- value = alpha + 1; // Just to trigger next condition
-
- if (value > alpha)
- {
- value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
-
- if (value > alpha)
{
- // Fail high! Set the boolean variable FailHigh to true, and
- // re-search the move using a PV search. The variable FailHigh
- // is used for time managment: We try to avoid aborting the
- // search prematurely during a fail high research.
- FailHigh = true;
- value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
+ // Try to reduce non-pv search depth by one ply if move seems not problematic,
+ // if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
+ if ( depth >= 3*OnePly // FIXME was newDepth
+ && !dangerous
+ && !captureOrPromotion
+ && !move_is_castle(move))
+ {
+ ss[0].reduction = pv_reduction(depth, RootMoveNumber - MultiPV + 1);
+ if (ss[0].reduction)
+ {
+ value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0);
+ doFullDepthSearch = (value > alpha);
+ }
+ }
+
+ if (doFullDepthSearch)
+ {
+ ss[0].reduction = Depth(0);
+ value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
+
+ if (value > alpha)
+ value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
+ }
}
- }
- }
- pos.undo_move(move);
+ pos.undo_move(move);
- // Finished searching the move. If AbortSearch is true, the search
- // was aborted because the user interrupted the search or because we
- // ran out of time. In this case, the return value of the search cannot
- // be trusted, and we break out of the loop without updating the best
- // move and/or PV.
- if (AbortSearch)
- break;
-
- // Remember beta-cutoff and searched nodes counts for this move. The
- // info is used to sort the root moves at the next iteration.
- int64_t our, their;
- BetaCounter.read(pos.side_to_move(), our, their);
- rml.set_beta_counters(i, our, their);
- rml.set_move_nodes(i, nodes_searched() - nodes);
-
- assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
-
- if (value <= alpha && i >= MultiPV)
- rml.set_move_score(i, -VALUE_INFINITE);
- else
- {
- // PV move or new best move!
-
- // Update PV
- rml.set_move_score(i, value);
- update_pv(ss, 0);
- TT.extract_pv(pos, ss[0].pv, PLY_MAX);
- rml.set_move_pv(i, ss[0].pv);
+ // Can we exit fail high loop ?
+ if (AbortSearch || value < beta)
+ break;
- if (MultiPV == 1)
- {
- // We record how often the best move has been changed in each
- // iteration. This information is used for time managment: When
- // the best move changes frequently, we allocate some more time.
- if (i > 0)
- BestMoveChangesByIteration[Iteration]++;
+ // We are failing high and going to do a research. It's important to update score
+ // before research in case we run out of time while researching.
+ rml.set_move_score(i, value);
+ update_pv(ss, 0);
+ TT.extract_pv(pos, ss[0].pv, PLY_MAX);
+ rml.set_move_pv(i, ss[0].pv);
// Print search information to the standard output
cout << "info depth " << Iteration
LogFile << pretty_pv(pos, current_search_time(), Iteration,
nodes_searched(), value, type, ss[0].pv) << endl;
}
- if (value > alpha)
- alpha = value;
- // Reset the global variable Problem to false if the value isn't too
- // far below the final value from the last iteration.
- if (value > IterationInfo[Iteration - 1].value - NoProblemMargin)
- Problem = false;
- }
- else // MultiPV > 1
+ // Prepare for a research after a fail high, each time with a wider window
+ researchCount++;
+ beta = Min(beta + AspirationDelta * (1 << researchCount), VALUE_INFINITE);
+
+ } // End of fail high loop
+
+ // Finished searching the move. If AbortSearch is true, the search
+ // was aborted because the user interrupted the search or because we
+ // ran out of time. In this case, the return value of the search cannot
+ // be trusted, and we break out of the loop without updating the best
+ // move and/or PV.
+ if (AbortSearch)
+ break;
+
+ // Remember beta-cutoff and searched nodes counts for this move. The
+ // info is used to sort the root moves at the next iteration.
+ int64_t our, their;
+ BetaCounter.read(pos.side_to_move(), our, their);
+ rml.set_beta_counters(i, our, their);
+ rml.set_move_nodes(i, nodes_searched() - nodes);
+
+ assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
+
+ if (value <= alpha && i >= MultiPV)
+ rml.set_move_score(i, -VALUE_INFINITE);
+ else
{
- rml.sort_multipv(i);
- for (int j = 0; j < Min(MultiPV, rml.move_count()); j++)
+ // PV move or new best move!
+
+ // Update PV
+ rml.set_move_score(i, value);
+ update_pv(ss, 0);
+ TT.extract_pv(pos, ss[0].pv, PLY_MAX);
+ rml.set_move_pv(i, ss[0].pv);
+
+ if (MultiPV == 1)
{
- cout << "info multipv " << j + 1
- << " score " << value_to_string(rml.get_move_score(j))
- << " depth " << ((j <= i)? Iteration : Iteration - 1)
- << " time " << current_search_time()
+ // We record how often the best move has been changed in each
+ // iteration. This information is used for time managment: When
+ // the best move changes frequently, we allocate some more time.
+ if (i > 0)
+ BestMoveChangesByIteration[Iteration]++;
+
+ // Print search information to the standard output
+ cout << "info depth " << Iteration
+ << " score " << value_to_string(value)
+ << ((value >= beta) ? " lowerbound" :
+ ((value <= alpha)? " upperbound" : ""))
+ << " time " << current_search_time()
<< " nodes " << nodes_searched()
- << " nps " << nps()
+ << " nps " << nps()
<< " pv ";
- for (int k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++)
- cout << rml.get_move_pv(j, k) << " ";
+ for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++)
+ cout << ss[0].pv[j] << " ";
cout << endl;
+
+ if (UseLogFile)
+ {
+ ValueType type = (value >= beta ? VALUE_TYPE_LOWER
+ : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
+
+ LogFile << pretty_pv(pos, current_search_time(), Iteration,
+ nodes_searched(), value, type, ss[0].pv) << endl;
+ }
+ if (value > alpha)
+ alpha = value;
}
- alpha = rml.get_move_score(Min(i, MultiPV-1));
- }
- } // PV move or new best move
+ else // MultiPV > 1
+ {
+ rml.sort_multipv(i);
+ for (int j = 0; j < Min(MultiPV, rml.move_count()); j++)
+ {
+ cout << "info multipv " << j + 1
+ << " score " << value_to_string(rml.get_move_score(j))
+ << " depth " << ((j <= i)? Iteration : Iteration - 1)
+ << " time " << current_search_time()
+ << " nodes " << nodes_searched()
+ << " nps " << nps()
+ << " pv ";
+
+ for (int k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++)
+ cout << rml.get_move_pv(j, k) << " ";
+
+ cout << endl;
+ }
+ alpha = rml.get_move_score(Min(i, MultiPV-1));
+ }
+ } // PV move or new best move
- assert(alpha >= oldAlpha);
+ assert(alpha >= oldAlpha);
+
+ AspirationFailLow = (alpha == oldAlpha);
+
+ if (AspirationFailLow && StopOnPonderhit)
+ StopOnPonderhit = false;
+ }
+
+ // Can we exit fail low loop ?
+ if (AbortSearch || alpha > oldAlpha)
+ break;
+
+ // Prepare for a research after a fail low, each time with a wider window
+ researchCount++;
+ alpha = Max(alpha - AspirationDelta * (1 << researchCount), -VALUE_INFINITE);
+ oldAlpha = alpha;
+
+ } // Fail low loop
- FailLow = (alpha == oldAlpha);
- }
return alpha;
}
Value oldAlpha, value;
bool isCheck, mateThreat, singleEvasion, moveIsCheck, captureOrPromotion, dangerous;
int moveCount = 0;
- Value bestValue = -VALUE_INFINITE;
+ Value bestValue = value = -VALUE_INFINITE;
if (depth < OnePly)
return qsearch(pos, ss, alpha, beta, Depth(0), ply, threadID);
tte = TT.retrieve(pos.get_key());
}
+ isCheck = pos.is_check();
+ if (!isCheck)
+ {
+ // Update gain statistics of the previous move that lead
+ // us in this position.
+ EvalInfo ei;
+ ss[ply].eval = evaluate(pos, ei, threadID);
+ update_gains(pos, ss[ply - 1].currentMove, ss[ply - 1].eval, ss[ply].eval);
+ }
+
// Initialize a MovePicker object for the current position, and prepare
// to search all moves
- isCheck = pos.is_check();
mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move()));
CheckInfo ci(pos);
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
{
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
if ( depth >= 3*OnePly
&& !dangerous
&& !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[ply]))
{
- double red = 0.5 + ln(moveCount) * ln(depth / 2) / 6.0;
- if (red >= 1.0)
- {
- ss[ply].reduction = Depth(int(floor(red * int(OnePly))));
- value = -search(pos, ss, -alpha, newDepth-ss[ply].reduction, ply+1, true, threadID);
- }
- else
- value = alpha + 1; // Just to trigger next condition
+ ss[ply].reduction = pv_reduction(depth, moveCount);
+ if (ss[ply].reduction)
+ {
+ value = -search(pos, ss, -alpha, newDepth-ss[ply].reduction, ply+1, true, threadID);
+ doFullDepthSearch = (value > alpha);
+ }
}
- else
- value = alpha + 1; // Just to trigger next condition
- if (value > alpha) // Go with full depth non-pv search
+ if (doFullDepthSearch) // Go with full depth non-pv search
{
ss[ply].reduction = Depth(0);
value = -search(pos, ss, -alpha, newDepth, ply+1, true, threadID);
if (value > alpha && value < beta)
- {
- // When the search fails high at ply 1 while searching the first
- // move at the root, set the flag failHighPly1. This is used for
- // time managment: We don't want to stop the search early in
- // such cases, because resolving the fail high at ply 1 could
- // result in a big drop in score at the root.
- if (ply == 1 && RootMoveNumber == 1)
- Threads[threadID].failHighPly1 = true;
-
- // A fail high occurred. Re-search at full window (pv search)
value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);
- Threads[threadID].failHighPly1 = false;
- }
}
}
pos.undo_move(move);
if (value == value_mate_in(ply + 1))
ss[ply].mateKiller = move;
}
- // If we are at ply 1, and we are searching the first root move at
- // ply 0, set the 'Problem' variable if the score has dropped a lot
- // (from the computer's point of view) since the previous iteration.
- if ( ply == 1
- && Iteration >= 2
- && -value <= IterationInfo[Iteration-1].value - ProblemMargin)
- Problem = true;
}
// Split?
Move ttMove, move;
Depth ext, newDepth;
Value bestValue, staticValue, nullValue, value, futilityValue, futilityValueScaled;
- bool isCheck, useFutilityPruning, singleEvasion, moveIsCheck, captureOrPromotion, dangerous;
+ bool isCheck, singleEvasion, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false;
int moveCount = 0;
- futilityValue = staticValue = bestValue = -VALUE_INFINITE;
+ futilityValue = staticValue = bestValue = value = -VALUE_INFINITE;
if (depth < OnePly)
return qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
// Calculate depth dependant futility pruning parameters
const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8));
- const int FutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2);
// Evaluate the position statically
- if (isCheck)
- ss[ply].eval = VALUE_NONE;
- else
+ if (!isCheck)
{
if (tte && (tte->type() & VALUE_TYPE_EVAL))
staticValue = value_from_tt(tte->value(), ply);
else
+ {
staticValue = evaluate(pos, ei, threadID);
+ ss[ply].evalInfo = &ei;
+ }
ss[ply].eval = staticValue;
- futilityValue = staticValue + FutilityValueMargin;
+ futilityValue = staticValue + FutilityMargins[int(depth)]; //FIXME: Remove me, only for split
staticValue = refine_eval(tte, staticValue, ply); // Enhance accuracy with TT value if possible
+ update_gains(pos, ss[ply - 1].currentMove, ss[ply - 1].eval, ss[ply].eval);
}
+ // Static null move pruning. We're betting that the opponent doesn't have
+ // a move that will reduce the score by more than FutilityMargins[int(depth)]
+ // if we do a null move.
+ if ( !isCheck
+ && allowNullmove
+ && depth < RazorDepth
+ && staticValue - FutilityMargins[int(depth)] >= beta)
+ return staticValue - FutilityMargins[int(depth)];
+
// Null move search
if ( allowNullmove
&& depth > OnePly
// Go with internal iterative deepening if we don't have a TT move
if (UseIIDAtNonPVNodes && ttMove == MOVE_NONE && depth >= 8*OnePly &&
- !isCheck && evaluate(pos, ei, threadID) >= beta - IIDMargin)
+ !isCheck && ss[ply].eval >= beta - IIDMargin)
{
search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID);
ttMove = ss[ply].pv[ply];
- tte = TT.retrieve(pos.get_key());
+ tte = TT.retrieve(posKey);
}
// Initialize a MovePicker object for the current position, and prepare
// to search all moves.
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
CheckInfo ci(pos);
- useFutilityPruning = depth < SelectiveDepth && !isCheck;
// Loop through all legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
movesSearched[moveCount++] = ss[ply].currentMove = move;
// Futility pruning
- if ( useFutilityPruning
+ if ( !isCheck
&& !dangerous
&& !captureOrPromotion
+ && !move_is_castle(move)
&& move != ttMove)
{
// Move count based pruning
continue;
// Value based pruning
- futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
+ Depth predictedDepth = newDepth;
+
+ //FIXME: We are ignoring condition: depth >= 3*OnePly, BUG??
+ ss[ply].reduction = nonpv_reduction(depth, moveCount);
+ if (ss[ply].reduction)
+ predictedDepth -= ss[ply].reduction;
- if (futilityValueScaled < beta)
+ if (predictedDepth < SelectiveDepth)
{
- if (futilityValueScaled > bestValue)
- bestValue = futilityValueScaled;
- continue;
+ int preFutilityValueMargin = 0;
+ if (predictedDepth >= OnePly)
+ preFutilityValueMargin = FutilityMargins[int(predictedDepth)];
+
+ preFutilityValueMargin += H.gain(pos.piece_on(move_from(move)), move_to(move)) + 45;
+
+ futilityValueScaled = ss[ply].eval + preFutilityValueMargin - moveCount * IncrementalFutilityMargin;
+
+ if (futilityValueScaled < beta)
+ {
+ if (futilityValueScaled > bestValue)
+ bestValue = futilityValueScaled;
+ continue;
+ }
}
}
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
if ( depth >= 3*OnePly
&& !dangerous
&& !captureOrPromotion
&& !move_is_castle(move)
- && !move_is_killer(move, ss[ply])
- /* && move != ttMove*/)
+ && !move_is_killer(move, ss[ply]))
{
- double red = 0.5 + ln(moveCount) * ln(depth / 2) / 3.0;
- if (red >= 1.0)
+ ss[ply].reduction = nonpv_reduction(depth, moveCount);
+ if (ss[ply].reduction)
{
- ss[ply].reduction = Depth(int(floor(red * int(OnePly))));
value = -search(pos, ss, -(beta-1), newDepth-ss[ply].reduction, ply+1, true, threadID);
+ doFullDepthSearch = (value >= beta);
}
- else
- value = beta; // Just to trigger next condition
}
- else
- value = beta; // Just to trigger next condition
- if (value >= beta) // Go with full depth non-pv search
+ if (doFullDepthSearch) // Go with full depth non-pv search
{
ss[ply].reduction = Depth(0);
value = -search(pos, ss, -(beta-1), newDepth, ply+1, true, threadID);
&& idle_thread_exists(threadID)
&& !AbortSearch
&& !thread_should_stop(threadID)
- && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue,
+ && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, //FIXME: SMP & futilityValue
depth, &moveCount, &mp, threadID, false))
break;
}
StateInfo st;
Move ttMove, move;
Value staticValue, bestValue, value, futilityBase, futilityValue;
- bool isCheck, enoughMaterial, moveIsCheck;
+ bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable;
const TTEntry* tte = NULL;
int moveCount = 0;
bool pvNode = (beta - alpha != 1);
+ Value oldAlpha = alpha;
// Initialize, and make an early exit in case of an aborted search,
// an instant draw, maximum ply reached, etc.
else
staticValue = evaluate(pos, ei, threadID);
+ if (!isCheck)
+ {
+ ss[ply].eval = staticValue;
+ update_gains(pos, ss[ply - 1].currentMove, ss[ply - 1].eval, ss[ply].eval);
+ }
+
// Initialize "stand pat score", and return it immediately if it is
// at least beta.
bestValue = staticValue;
if (bestValue >= beta)
{
// Store the score to avoid a future costly evaluation() call
- if (!isCheck && !tte && ei.futilityMargin == 0)
+ if (!isCheck && !tte && ei.futilityMargin[pos.side_to_move()] == 0)
TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EV_LO, Depth(-127*OnePly), MOVE_NONE);
return bestValue;
if (bestValue > alpha)
alpha = bestValue;
+ // If we are near beta then try to get a cutoff pushing checks a bit further
+ bool deepChecks = depth == -OnePly && staticValue >= beta - PawnValueMidgame / 8;
+
// 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.
- MovePicker mp = MovePicker(pos, ttMove, depth, H);
+ // to search the moves. Because the depth is <= 0 here, only captures,
+ // queen promotions and checks (only if depth == 0 or depth == -OnePly
+ // and we are near beta) will be generated.
+ MovePicker mp = MovePicker(pos, ttMove, deepChecks ? Depth(0) : depth, H);
CheckInfo ci(pos);
enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
- futilityBase = staticValue + FutilityMarginQS + ei.futilityMargin;
+ futilityBase = staticValue + FutilityMarginQS + ei.futilityMargin[pos.side_to_move()];
// Loop through the moves until no moves remain or a beta cutoff
// occurs.
}
}
- // Don't search captures and checks with negative SEE values
- if ( !isCheck
+ // Detect blocking evasions that are candidate to be pruned
+ evasionPrunable = isCheck
+ && bestValue != -VALUE_INFINITE
+ && !pos.move_is_capture(move)
+ && pos.type_of_piece_on(move_from(move)) != KING
+ && !pos.can_castle(pos.side_to_move());
+
+ // Don't search moves with negative SEE values
+ if ( (!isCheck || evasionPrunable)
&& move != ttMove
&& !move_is_promotion(move)
&& pos.see_sign(move) < 0)
// Update transposition table
Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
- if (bestValue < beta)
+ if (bestValue <= oldAlpha)
{
// If bestValue isn't changed it means it is still the static evaluation
// of the node, so keep this info to avoid a future evaluation() call.
- ValueType type = (bestValue == staticValue && !ei.futilityMargin ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER);
+ ValueType type = (bestValue == staticValue && !ei.futilityMargin[pos.side_to_move()] ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER);
TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE);
}
- else
+ else if (bestValue >= beta)
{
move = ss[ply].pv[ply];
TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move);
if (!pos.move_is_capture_or_promotion(move))
update_killers(move, ss[ply]);
}
+ else
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, d, ss[ply].pv[ply]);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
- Position pos = Position(sp->pos);
+ Position pos(*sp->pos);
CheckInfo ci(pos);
SearchStack* ss = sp->sstack[threadID];
- Value value;
+ Value value = -VALUE_INFINITE;
Move move;
+ int moveCount;
bool isCheck = pos.is_check();
bool useFutilityPruning = sp->depth < SelectiveDepth
&& !isCheck;
const int FutilityMoveCountMargin = 3 + (1 << (3 * int(sp->depth) / 8));
- while ( sp->bestValue < sp->beta
+ while ( lock_grab_bool(&(sp->lock))
+ && sp->bestValue < sp->beta
&& !thread_should_stop(threadID)
- && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
+ && (move = sp->mp->get_next_move()) != MOVE_NONE)
{
+ moveCount = ++sp->moves;
+ lock_release(&(sp->lock));
+
assert(move_is_ok(move));
bool moveIsCheck = pos.move_is_check(move, ci);
bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
- lock_grab(&(sp->lock));
- int moveCount = ++sp->moves;
- lock_release(&(sp->lock));
-
ss[sp->ply].currentMove = move;
- // Decide the new search depth.
+ // Decide the new search depth
bool dangerous;
Depth ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, false, false, &dangerous);
Depth newDepth = sp->depth - OnePly + ext;
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
if ( !dangerous
&& !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply]))
{
- double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 3.0;
- if (red >= 1.0)
+ ss[sp->ply].reduction = nonpv_reduction(sp->depth, moveCount);
+ if (ss[sp->ply].reduction)
{
- ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly))));
value = -search(pos, ss, -(sp->beta-1), newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
+ doFullDepthSearch = (value >= sp->beta);
}
- else
- value = sp->beta; // Just to trigger next condition
}
- else
- value = sp->beta; // Just to trigger next condition
- if (value >= sp->beta) // Go with full depth non-pv search
+ if (doFullDepthSearch) // Go with full depth non-pv search
{
ss[sp->ply].reduction = Depth(0);
value = -search(pos, ss, -(sp->beta - 1), newDepth, sp->ply+1, true, threadID);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
if (thread_should_stop(threadID))
+ {
+ lock_grab(&(sp->lock));
break;
+ }
// New best move?
if (value > sp->bestValue) // Less then 2% of cases
}
}
- lock_grab(&(sp->lock));
+ /* Here we have the lock still grabbed */
// If this is the master thread and we have been asked to stop because of
// a beta cutoff higher up in the tree, stop all slave threads.
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
- Position pos = Position(sp->pos);
+ Position pos(*sp->pos);
CheckInfo ci(pos);
SearchStack* ss = sp->sstack[threadID];
- Value value;
+ Value value = -VALUE_INFINITE;
+ int moveCount;
Move move;
- while ( sp->alpha < sp->beta
+ while ( lock_grab_bool(&(sp->lock))
+ && sp->alpha < sp->beta
&& !thread_should_stop(threadID)
- && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
+ && (move = sp->mp->get_next_move()) != MOVE_NONE)
{
- bool moveIsCheck = pos.move_is_check(move, ci);
- bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
+ moveCount = ++sp->moves;
+ lock_release(&(sp->lock));
assert(move_is_ok(move));
- lock_grab(&(sp->lock));
- int moveCount = ++sp->moves;
- lock_release(&(sp->lock));
+ bool moveIsCheck = pos.move_is_check(move, ci);
+ bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
ss[sp->ply].currentMove = move;
- // Decide the new search depth.
+ // Decide the new search depth
bool dangerous;
Depth ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
Depth newDepth = sp->depth - OnePly + ext;
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
if ( !dangerous
&& !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply]))
{
- double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 6.0;
- if (red >= 1.0)
+ ss[sp->ply].reduction = pv_reduction(sp->depth, moveCount);
+ if (ss[sp->ply].reduction)
{
- ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly))));
- value = -search(pos, ss, -sp->alpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
+ Value localAlpha = sp->alpha;
+ value = -search(pos, ss, -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
+ doFullDepthSearch = (value > localAlpha);
}
- else
- value = sp->alpha + 1; // Just to trigger next condition
}
- else
- value = sp->alpha + 1; // Just to trigger next condition
- if (value > sp->alpha) // Go with full depth non-pv search
+ if (doFullDepthSearch) // Go with full depth non-pv search
{
+ Value localAlpha = sp->alpha;
ss[sp->ply].reduction = Depth(0);
- value = -search(pos, ss, -sp->alpha, newDepth, sp->ply+1, true, threadID);
+ value = -search(pos, ss, -localAlpha, newDepth, sp->ply+1, true, threadID);
- if (value > sp->alpha && value < sp->beta)
+ if (value > localAlpha && value < sp->beta)
{
- // When the search fails high at ply 1 while searching the first
- // move at the root, set the flag failHighPly1. This is used for
- // time managment: We don't want to stop the search early in
- // such cases, because resolving the fail high at ply 1 could
- // result in a big drop in score at the root.
- if (sp->ply == 1 && RootMoveNumber == 1)
- Threads[threadID].failHighPly1 = true;
-
- value = -search_pv(pos, ss, -sp->beta, -sp->alpha, newDepth, sp->ply+1, threadID);
- Threads[threadID].failHighPly1 = false;
+ // If another thread has failed high then sp->alpha has been increased
+ // to be higher or equal then beta, if so, avoid to start a PV search.
+ localAlpha = sp->alpha;
+ if (localAlpha < sp->beta)
+ value = -search_pv(pos, ss, -sp->beta, -localAlpha, newDepth, sp->ply+1, threadID);
+ else
+ assert(thread_should_stop(threadID));
}
}
pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
if (thread_should_stop(threadID))
+ {
+ lock_grab(&(sp->lock));
break;
+ }
// New best move?
- lock_grab(&(sp->lock));
- if (value > sp->bestValue && !thread_should_stop(threadID))
+ if (value > sp->bestValue) // Less then 2% of cases
{
- sp->bestValue = value;
- if (value > sp->alpha)
+ lock_grab(&(sp->lock));
+ if (value > sp->bestValue && !thread_should_stop(threadID))
{
- sp->alpha = value;
- sp_update_pv(sp->parentSstack, ss, sp->ply);
- if (value == value_mate_in(sp->ply + 1))
- ss[sp->ply].mateKiller = move;
-
- if (value >= sp->beta)
+ sp->bestValue = value;
+ if (value > sp->alpha)
{
- for (int i = 0; i < ActiveThreads; i++)
- if (i != threadID && (i == sp->master || sp->slaves[i]))
- Threads[i].stop = true;
+ // Ask threads to stop before to modify sp->alpha
+ if (value >= sp->beta)
+ {
+ for (int i = 0; i < ActiveThreads; i++)
+ if (i != threadID && (i == sp->master || sp->slaves[i]))
+ Threads[i].stop = true;
- sp->finished = true;
+ sp->finished = true;
+ }
+
+ sp->alpha = value;
+
+ sp_update_pv(sp->parentSstack, ss, sp->ply);
+ if (value == value_mate_in(sp->ply + 1))
+ ss[sp->ply].mateKiller = move;
}
- }
- // If we are at ply 1, and we are searching the first root move at
- // ply 0, set the 'Problem' variable if the score has dropped a lot
- // (from the computer's point of view) since the previous iteration.
- if ( sp->ply == 1
- && Iteration >= 2
- && -value <= IterationInfo[Iteration-1].value - ProblemMargin)
- Problem = true;
+ }
+ lock_release(&(sp->lock));
}
- lock_release(&(sp->lock));
}
- lock_grab(&(sp->lock));
+ /* Here we have the lock still grabbed */
// If this is the master thread and we have been asked to stop because of
// a beta cutoff higher up in the tree, stop all slave threads.
RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) : count(0) {
+ SearchStack ss[PLY_MAX_PLUS_2];
MoveStack mlist[MaxRootMoves];
+ StateInfo st;
bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
// Generate all legal moves
continue;
// Find a quick score for the move
- StateInfo st;
- SearchStack ss[PLY_MAX_PLUS_2];
init_ss_array(ss);
-
+ pos.do_move(cur->move, st);
moves[count].move = cur->move;
- pos.do_move(moves[count].move, st);
moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0);
- pos.undo_move(moves[count].move);
- moves[count].pv[0] = moves[count].move;
+ moves[count].pv[0] = cur->move;
moves[count].pv[1] = MOVE_NONE;
+ pos.undo_move(cur->move);
count++;
}
sort();
Square mfrom, mto, tfrom, tto;
- // Prune if there isn't any threat move and
- // is not a castling move (common case).
- if (threat == MOVE_NONE && !move_is_castle(m))
+ // Prune if there isn't any threat move
+ if (threat == MOVE_NONE)
return true;
mfrom = move_from(m);
tfrom = move_from(threat);
tto = move_to(threat);
- // Case 1: Castling moves are never pruned
- if (move_is_castle(m))
- return false;
-
- // Case 2: Don't prune moves which move the threatened piece
+ // Case 1: Don't prune moves which move the threatened piece
if (mfrom == tto)
return false;
- // Case 3: If the threatened piece has value less than or equal to the
+ // Case 2: If the threatened piece has value less than or equal to the
// value of the threatening piece, don't prune move which defend it.
if ( pos.move_is_capture(threat)
&& ( pos.midgame_value_of_piece_on(tfrom) >= pos.midgame_value_of_piece_on(tto)
&& pos.move_attacks_square(m, tto))
return false;
- // Case 4: If the moving piece in the threatened move is a slider, don't
+ // Case 3: If the moving piece in the threatened move is a slider, don't
// prune safe moves which block its ray.
if ( piece_is_slider(pos.piece_on(tfrom))
&& bit_is_set(squares_between(tfrom, tto), mto)
return defaultEval;
}
+
// update_history() registers a good move that produced a beta-cutoff
// in history and marks as failures all the other moves of that ply.
}
- // fail_high_ply_1() checks if some thread is currently resolving a fail
- // high at ply 1 at the node below the first root node. This information
- // is used for time management.
-
- bool fail_high_ply_1() {
+ // update_gains() updates the gains table of a non-capture move given
+ // the static position evaluation before and after the move.
- for (int i = 0; i < ActiveThreads; i++)
- if (Threads[i].failHighPly1)
- return true;
+ void update_gains(const Position& pos, Move m, Value before, Value after) {
- return false;
+ if ( m != MOVE_NULL
+ && before != VALUE_NONE
+ && after != VALUE_NONE
+ && pos.captured_piece() == NO_PIECE_TYPE
+ && !move_is_castle(m)
+ && !move_is_promotion(m))
+ H.set_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after));
}
return;
bool stillAtFirstMove = RootMoveNumber == 1
- && !FailLow
+ && !AspirationFailLow
&& t > MaxSearchTime + ExtraSearchTime;
- bool noProblemFound = !FailHigh
- && !FailLow
- && !fail_high_ply_1()
- && !Problem
- && t > 6 * (MaxSearchTime + ExtraSearchTime);
-
bool noMoreTime = t > AbsoluteMaxSearchTime
- || stillAtFirstMove //FIXME: We are not checking any problem flags, BUG?
- || noProblemFound;
+ || stillAtFirstMove;
if ( (Iteration >= 3 && UseTimeManagement && noMoreTime)
|| (ExactMaxTime && t >= ExactMaxTime)
PonderSearch = false;
bool stillAtFirstMove = RootMoveNumber == 1
- && !FailLow
+ && !AspirationFailLow
&& t > MaxSearchTime + ExtraSearchTime;
- bool noProblemFound = !FailHigh
- && !FailLow
- && !fail_high_ply_1()
- && !Problem
- && t > 6 * (MaxSearchTime + ExtraSearchTime);
-
bool noMoreTime = t > AbsoluteMaxSearchTime
- || stillAtFirstMove
- || noProblemFound;
+ || stillAtFirstMove;
if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit))
AbortSearch = true;
// If this thread has been assigned work, launch a search
if (Threads[threadID].workIsWaiting)
{
+ assert(!Threads[threadID].idle);
+
Threads[threadID].workIsWaiting = false;
if (Threads[threadID].splitPoint->pvNode)
sp_search_pv(Threads[threadID].splitPoint, threadID);
if (!Threads[slave].idle || slave == master)
return false;
- if (Threads[slave].activeSplitPoints == 0)
+ // Make a local copy to be sure doesn't change under our feet
+ int localActiveSplitPoints = Threads[slave].activeSplitPoints;
+
+ if (localActiveSplitPoints == 0)
// No active split points means that the thread is available as
// a slave for any other thread.
return true;
if (ActiveThreads == 2)
return true;
- // Apply the "helpful master" concept if possible
- if (SplitPointStack[slave][Threads[slave].activeSplitPoints - 1].slaves[master])
+ // Apply the "helpful master" concept if possible. Use localActiveSplitPoints
+ // that is known to be > 0, instead of Threads[slave].activeSplitPoints that
+ // could have been set to 0 by another thread leading to an out of bound access.
+ if (SplitPointStack[slave][localActiveSplitPoints - 1].slaves[master])
return true;
return false;
assert(ActiveThreads > 1);
SplitPoint* splitPoint;
- int i;
lock_grab(&MPLock);
splitPoint = SplitPointStack[master] + Threads[master].activeSplitPoints;
Threads[master].activeSplitPoints++;
- // Initialize the split point object and copy current position
+ // Initialize the split point object
splitPoint->parent = Threads[master].splitPoint;
splitPoint->finished = false;
splitPoint->ply = ply;
splitPoint->mp = mp;
splitPoint->moves = *moves;
splitPoint->cpus = 1;
- splitPoint->pos.copy(p);
+ splitPoint->pos = &p;
splitPoint->parentSstack = sstck;
- for (i = 0; i < ActiveThreads; i++)
+ for (int i = 0; i < ActiveThreads; i++)
splitPoint->slaves[i] = 0;
- // Copy the current search stack to the master thread
- memcpy(splitPoint->sstack[master], sstck, (ply+1) * sizeof(SearchStack));
+ Threads[master].idle = false;
+ Threads[master].stop = false;
Threads[master].splitPoint = splitPoint;
- // Make copies of the current position and search stack for each thread
- for (i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
+ // Allocate available threads setting idle flag to false
+ for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
if (thread_is_available(i, master))
{
- memcpy(splitPoint->sstack[i], sstck, (ply+1) * sizeof(SearchStack));
+ Threads[i].idle = false;
+ Threads[i].stop = false;
Threads[i].splitPoint = splitPoint;
splitPoint->slaves[i] = 1;
splitPoint->cpus++;
}
+ assert(splitPoint->cpus > 1);
+
+ // We can release the lock because master and slave threads are already booked
+ lock_release(&MPLock);
+
// Tell the threads that they have work to do. This will make them leave
- // their idle loop.
- for (i = 0; i < ActiveThreads; i++)
+ // their idle loop. But before copy search stack tail for each thread.
+ for (int i = 0; i < ActiveThreads; i++)
if (i == master || splitPoint->slaves[i])
{
- Threads[i].workIsWaiting = true;
- Threads[i].idle = false;
- Threads[i].stop = false;
+ memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 4 * sizeof(SearchStack));
+ Threads[i].workIsWaiting = true; // This makes the slave to exit from idle_loop()
}
- lock_release(&MPLock);
-
// Everything is set up. The master thread enters the idle loop, from
// which it will instantly launch a search, because its workIsWaiting
// slot is 'true'. We send the split point as a second parameter to the
projects / stockfish / blobdiff