/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2009 Marco Costalba
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
////
#include <cassert>
+#include <cstring>
#include <fstream>
#include <iostream>
#include <sstream>
#include "evaluate.h"
#include "history.h"
#include "misc.h"
+#include "movegen.h"
#include "movepick.h"
+#include "lock.h"
#include "san.h"
#include "search.h"
#include "thread.h"
/// 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
// to the number of beta cutoffs occurred under their subtree during
- // the last iteration.
+ // the last iteration. The counters are per thread variables to avoid
+ // concurrent accessing under SMP case.
struct BetaCounterType {
void clear();
void add(Color us, Depth d, int threadID);
void read(Color us, int64_t& our, int64_t& their);
-
- int64_t hits[THREAD_MAX][2];
};
class RootMoveList {
public:
- RootMoveList(Position &pos, Move searchMoves[]);
+ RootMoveList(Position& pos, Move searchMoves[]);
inline Move get_move(int moveNum) const;
inline Value get_move_score(int moveNum) const;
inline void set_move_score(int moveNum, Value score);
};
- /// Constants and variables
+ /// Constants
- // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV
- // nodes:
- int LMRPVMoves = 15;
- int LMRNonPVMoves = 4;
-
- // Depth limit for use of dynamic threat detection:
- Depth ThreatDepth = 5*OnePly;
+ // Search depth at iteration 1
+ const Depth InitialDepth = OnePly /*+ OnePly/2*/;
- // Depth limit for selective search:
- Depth SelectiveDepth = 7*OnePly;
+ // Depth limit for selective search
+ const Depth SelectiveDepth = 7 * OnePly;
// Use internal iterative deepening?
const bool UseIIDAtPVNodes = true;
const bool UseIIDAtNonPVNodes = false;
- // Use null move driven internal iterative deepening?
- bool UseNullDrivenIID = false;
-
- // Internal iterative deepening margin. At Non-PV moves, when
- // UseIIDAtNonPVNodes is true, we do an internal iterative deepening search
- // when the static evaluation is at most IIDMargin below beta.
+ // Internal iterative deepening margin. At Non-PV moves, when
+ // UseIIDAtNonPVNodes is true, we do an internal iterative deepening
+ // search when the static evaluation is at most IIDMargin below beta.
const Value IIDMargin = Value(0x100);
- // Easy move margin. An easy move candidate must be at least this much
+ // Easy move margin. An easy move candidate must be at least this much
// 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
+ // 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
+ // 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 approximate
+ // Null move margin. A null move search will not be done if the approximate
// evaluation of the position is more than NullMoveMargin below beta.
const Value NullMoveMargin = Value(0x300);
- // Pruning criterions. See the code and comments in ok_to_prune() to
+ // Pruning criterions. See the code and comments in ok_to_prune() to
// understand their precise meaning.
- const bool PruneEscapeMoves = false;
+ const bool PruneEscapeMoves = false;
const bool PruneDefendingMoves = false;
- const bool PruneBlockingMoves = false;
-
- // Use futility pruning?
- bool UseQSearchFutilityPruning = true;
- bool UseFutilityPruning = true;
+ const bool PruneBlockingMoves = false;
// Margins for futility pruning in the quiescence search, and at frontier
- // and near frontier nodes
- Value FutilityMarginQS = Value(0x80);
- Value FutilityMargins[6] = { Value(0x100), Value(0x200), Value(0x250),
- Value(0x2A0), Value(0x340), Value(0x3A0) };
+ // and near frontier nodes.
+ const Value FutilityMarginQS = Value(0x80);
+ // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply
+ const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270),
+ // 4 ply 4.5 ply 5 ply 5.5 ply 6 ply 6.5 ply
+ Value(0x2A0), Value(0x2C0), Value(0x340), Value(0x360), Value(0x3A0), Value(0x3C0) };
// Razoring
- const bool RazorAtDepthOne = false;
- Depth RazorDepth = 4*OnePly;
- Value RazorMargin = Value(0x300);
+ const Depth RazorDepth = 4*OnePly;
- // Last seconds noise filtering (LSN)
- bool UseLSNFiltering = false;
- bool looseOnTime = false;
- int LSNTime = 4 * 1000; // In milliseconds
- Value LSNValue = Value(0x200);
+ // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply
+ const Value RazorMargins[6] = { Value(0x180), Value(0x300), Value(0x300), Value(0x3C0), Value(0x3C0), Value(0x3C0) };
- // Extensions. Array index 0 is used at non-PV nodes, index 1 at PV nodes.
- Depth CheckExtension[2] = {OnePly, OnePly};
- Depth SingleReplyExtension[2] = {OnePly / 2, OnePly / 2};
- Depth PawnPushTo7thExtension[2] = {OnePly / 2, OnePly / 2};
- Depth PassedPawnExtension[2] = {Depth(0), Depth(0)};
- Depth PawnEndgameExtension[2] = {OnePly, OnePly};
- Depth MateThreatExtension[2] = {Depth(0), Depth(0)};
+ // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply
+ const Value RazorApprMargins[6] = { Value(0x520), Value(0x300), Value(0x300), Value(0x300), Value(0x300), Value(0x300) };
- // Search depth at iteration 1
- const Depth InitialDepth = OnePly /*+ OnePly/2*/;
+ // The main transposition table
+ TranspositionTable TT;
- // Node counters
- int NodesSincePoll;
- int NodesBetweenPolls = 30000;
+
+ /// Variables initialized by UCI options
+
+ // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV nodes
+ int LMRPVMoves, LMRNonPVMoves; // heavy SMP read access for the latter
+
+ // Depth limit for use of dynamic threat detection
+ Depth ThreatDepth; // heavy SMP read access
+
+ // Last seconds noise filtering (LSN)
+ bool UseLSNFiltering;
+ bool looseOnTime = false;
+ int LSNTime; // In milliseconds
+ Value LSNValue;
+
+ // Extensions. Array index 0 is used at non-PV nodes, index 1 at PV nodes.
+ // There is heavy SMP read access on these arrays
+ Depth CheckExtension[2], SingleReplyExtension[2], PawnPushTo7thExtension[2];
+ Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2];
// Iteration counters
int Iteration;
- bool LastIterations;
- BetaCounterType BetaCounter;
+ BetaCounterType BetaCounter; // has per-thread internal data
- // Scores and number of times the best move changed for each iteration:
- Value ValueByIteration[PLY_MAX_PLUS_2];
+ // Scores and number of times the best move changed for each iteration
+ IterationInfoType IterationInfo[PLY_MAX_PLUS_2];
int BestMoveChangesByIteration[PLY_MAX_PLUS_2];
// MultiPV mode
- int MultiPV = 1;
+ int MultiPV;
// Time managment variables
int SearchStartTime;
int MaxNodes, MaxDepth;
int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime;
- Move BestRootMove, PonderMove, EasyMove;
+ Move EasyMove;
int RootMoveNumber;
bool InfiniteSearch;
bool PonderSearch;
bool StopOnPonderhit;
- bool AbortSearch;
+ bool AbortSearch; // heavy SMP read access
bool Quit;
bool FailHigh;
+ bool FailLow;
bool Problem;
bool PonderingEnabled;
int ExactMaxTime;
// Show current line?
- bool ShowCurrentLine = false;
+ bool ShowCurrentLine;
// Log file
- bool UseLogFile = false;
+ bool UseLogFile;
std::ofstream LogFile;
// MP related variables
- Depth MinimumSplitDepth = 4*OnePly;
- int MaxThreadsPerSplitPoint = 4;
+ int ActiveThreads = 1;
+ Depth MinimumSplitDepth;
+ int MaxThreadsPerSplitPoint;
Thread Threads[THREAD_MAX];
Lock MPLock;
+ Lock IOLock;
bool AllThreadsShouldExit = false;
const int MaxActiveSplitPoints = 8;
SplitPoint SplitPointStack[THREAD_MAX][MaxActiveSplitPoints];
HANDLE SitIdleEvent[THREAD_MAX];
#endif
+ // Node counters, used only by thread[0] but try to keep in different
+ // cache lines (64 bytes each) from the heavy SMP read accessed variables.
+ int NodesSincePoll;
+ int NodesBetweenPolls = 30000;
+
/// Functions
- Value id_loop(const Position &pos, Move searchMoves[]);
- Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml);
- 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);
- Value qsearch(Position &pos, SearchStack ss[], Value alpha, Value beta,
- Depth depth, int ply, int threadID);
- void sp_search(SplitPoint *sp, int threadID);
- void sp_search_pv(SplitPoint *sp, int threadID);
- void init_search_stack(SearchStack& ss);
- void init_search_stack(SearchStack ss[]);
- void init_node(const Position &pos, SearchStack ss[], int ply, int threadID);
+ Value id_loop(const Position& pos, Move searchMoves[]);
+ Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value alpha, 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);
+ Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
+ void sp_search(SplitPoint* sp, int threadID);
+ void sp_search_pv(SplitPoint* sp, int threadID);
+ void init_node(SearchStack ss[], int ply, int threadID);
void update_pv(SearchStack ss[], int ply);
- void sp_update_pv(SearchStack *pss, SearchStack ss[], int ply);
- bool connected_moves(const Position &pos, Move m1, Move m2);
+ void sp_update_pv(SearchStack* pss, SearchStack ss[], int ply);
+ bool connected_moves(const Position& pos, Move m1, Move m2);
bool value_is_mate(Value value);
bool move_is_killer(Move m, const SearchStack& ss);
- Depth extension(const Position &pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
- bool ok_to_do_nullmove(const Position &pos);
- bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d);
+ Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
+ bool ok_to_do_nullmove(const Position& pos);
+ bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d, const History& H);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
- bool ok_to_history(const Position &pos, Move m);
- void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount);
+ bool ok_to_history(const Position& pos, Move m);
+ void update_history(const Position& pos, Move m, Depth depth, History& H, Move movesSearched[], int moveCount);
void update_killers(Move m, SearchStack& ss);
bool fail_high_ply_1();
void print_current_line(SearchStack ss[], int ply, int threadID);
void wait_for_stop_or_ponderhit();
- void idle_loop(int threadID, SplitPoint *waitSp);
+ void idle_loop(int threadID, SplitPoint* waitSp);
void init_split_point_stack();
void destroy_split_point_stack();
bool thread_should_stop(int threadID);
bool thread_is_available(int slave, int master);
bool idle_thread_exists(int master);
- bool split(const Position &pos, SearchStack *ss, int ply,
- Value *alpha, Value *beta, Value *bestValue, Depth depth,
- int *moves, MovePicker *mp, Bitboard dcCandidates, int master,
- bool pvNode);
+ bool split(const Position& pos, SearchStack* ss, int ply,
+ Value *alpha, Value *beta, Value *bestValue, Depth depth, int *moves,
+ MovePicker *mp, Bitboard dcCandidates, int master, bool pvNode);
void wake_sleeping_threads();
#if !defined(_MSC_VER)
}
-////
-//// Global variables
-////
-
-// The main transposition table
-TranspositionTable TT = TranspositionTable(TTDefaultSize);
-
-
-// Number of active threads:
-int ActiveThreads = 1;
-
-// Locks. In principle, there is no need for IOLock to be a global variable,
-// but it could turn out to be useful for debugging.
-Lock IOLock;
-
-History H; // Should be made local?
-
-// The empty search stack
-SearchStack EmptySearchStack;
-
-
////
//// Functions
////
/// think() is the external interface to Stockfish's search, and is called when
-/// the program receives the UCI 'go' command. It initializes various
-/// search-related global variables, and calls root_search()
+/// the program receives the UCI 'go' command. It initializes various
+/// search-related global variables, and calls root_search(). It returns false
+/// when a quit command is received during the search.
-void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
+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[]) {
{
Move bookMove;
if (get_option_value_string("Book File") != OpeningBook.file_name())
- {
- OpeningBook.close();
OpeningBook.open("book.bin");
- }
+
bookMove = OpeningBook.get_move(pos);
if (bookMove != MOVE_NONE)
{
std::cout << "bestmove " << bookMove << std::endl;
- return;
+ return true;
}
}
// Initialize global search variables
Idle = false;
SearchStartTime = get_system_time();
- BestRootMove = MOVE_NONE;
- PonderMove = MOVE_NONE;
EasyMove = MOVE_NONE;
for (int i = 0; i < THREAD_MAX; i++)
{
AbortSearch = false;
Quit = false;
FailHigh = false;
+ FailLow = false;
Problem = false;
ExactMaxTime = maxTime;
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;
- SelectiveDepth = get_option_value_int("Selective Plies") * OnePly;
+ 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");
ShowCurrentLine = get_option_value_bool("UCI_ShowCurrLine");
if (UseLogFile)
LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
- UseNullDrivenIID = get_option_value_bool("Null driven IID");
- UseQSearchFutilityPruning = get_option_value_bool("Futility Pruning (Quiescence Search)");
- UseFutilityPruning = get_option_value_bool("Futility Pruning (Main Search)");
-
- FutilityMarginQS = value_from_centipawns(get_option_value_int("Futility Margin (Quiescence Search)"));
- int fmScale = get_option_value_int("Futility Margin Scale Factor (Main Search)");
- for (int i = 0; i < 6; i++)
- FutilityMargins[i] = (FutilityMargins[i] * fmScale) / 100;
-
- RazorDepth = (get_option_value_int("Maximum Razoring Depth") + 1) * OnePly;
- RazorMargin = value_from_centipawns(get_option_value_int("Razoring Margin"));
-
UseLSNFiltering = get_option_value_bool("LSN filtering");
LSNTime = get_option_value_int("LSN Time Margin (sec)") * 1000;
LSNValue = value_from_centipawns(get_option_value_int("LSN Value Margin"));
init_eval(ActiveThreads);
}
- // Wake up sleeping threads:
+ // Wake up sleeping threads
wake_sleeping_threads();
for (int i = 1; i < ActiveThreads; i++)
assert(thread_is_available(i, 0));
- // Set thinking time:
+ // Set thinking time
int myTime = time[side_to_move];
int myIncrement = increment[side_to_move];
NodesBetweenPolls = 30000;
- // Write information to search log file:
+ // Write information to search log file
if (UseLogFile)
LogFile << "Searching: " << pos.to_fen() << std::endl
- << "infinite: " << infinite
- << " ponder: " << ponder
- << " time: " << myTime
+ << "infinite: " << infinite
+ << " ponder: " << ponder
+ << " time: " << myTime
<< " increment: " << myIncrement
<< " moves to go: " << movesToGo << std::endl;
- // We're ready to start thinking. Call the iterative deepening loop
- // function:
+ // We're ready to start thinking. Call the iterative deepening loop function
if (!looseOnTime)
{
Value v = id_loop(pos, searchMoves);
if (UseLogFile)
LogFile.close();
- if (Quit)
- {
- OpeningBook.close();
- stop_threads();
- quit_eval();
- exit(0);
- }
Idle = true;
+ return !Quit;
}
for (i = 0; i < THREAD_MAX; i++)
Threads[i].activeSplitPoints = 0;
- // Initialize global locks:
+ // Initialize global locks
lock_init(&MPLock, NULL);
lock_init(&IOLock, NULL);
CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID);
#endif
- // Wait until the thread has finished launching:
+ // Wait until the thread has finished launching
while (!Threads[i].running);
}
-
- // Init also the empty search stack
- init_search_stack(EmptySearchStack);
}
}
+// SearchStack::init() initializes a search stack. Used at the beginning of a
+// new search from the root.
+void SearchStack::init(int ply) {
+
+ pv[ply] = pv[ply + 1] = MOVE_NONE;
+ currentMove = threatMove = MOVE_NONE;
+ reduction = Depth(0);
+}
+
+void SearchStack::initKillers() {
+
+ mateKiller = MOVE_NONE;
+ for (int i = 0; i < KILLER_MAX; i++)
+ killers[i] = MOVE_NONE;
+}
+
namespace {
// id_loop() is the main iterative deepening loop. It calls root_search
// been consumed, the user stops the search, or the maximum search depth is
// reached.
- Value id_loop(const Position &pos, Move searchMoves[]) {
+ Value id_loop(const Position& pos, Move searchMoves[]) {
Position p(pos);
SearchStack ss[PLY_MAX_PLUS_2];
// Initialize
TT.new_search();
- H.clear();
- init_search_stack(ss);
+ for (int i = 0; i < THREAD_MAX; i++)
+ Threads[i].H.clear();
- ValueByIteration[0] = Value(0);
- ValueByIteration[1] = rml.get_move_score(0);
+ for (int i = 0; i < 3; i++)
+ {
+ ss[i].init(i);
+ ss[i].initKillers();
+ }
+ IterationInfo[1] = IterationInfoType(rml.get_move_score(0), rml.get_move_score(0));
Iteration = 1;
- LastIterations = false;
EasyMove = rml.scan_for_easy_move();
// Iterative deepening loop
- while (!AbortSearch && Iteration < PLY_MAX)
+ while (Iteration < PLY_MAX)
{
// Initialize iteration
rml.sort();
std::cout << "info depth " << Iteration << std::endl;
+ // Calculate dynamic search window based on previous iterations
+ Value alpha, beta;
+
+ if (MultiPV == 1 && Iteration >= 6 && abs(IterationInfo[Iteration - 1].value) < VALUE_KNOWN_WIN)
+ {
+ int prevDelta1 = IterationInfo[Iteration - 1].speculatedValue - IterationInfo[Iteration - 2].speculatedValue;
+ int prevDelta2 = IterationInfo[Iteration - 2].speculatedValue - IterationInfo[Iteration - 3].speculatedValue;
+
+ int delta = Max(2 * abs(prevDelta1) + abs(prevDelta2), ProblemMargin);
+
+ alpha = Max(IterationInfo[Iteration - 1].value - delta, -VALUE_INFINITE);
+ beta = Min(IterationInfo[Iteration - 1].value + delta, VALUE_INFINITE);
+ }
+ else
+ {
+ alpha = - VALUE_INFINITE;
+ beta = VALUE_INFINITE;
+ }
+
// Search to the current depth
- ValueByIteration[Iteration] = root_search(p, ss, rml);
+ Value value = root_search(p, ss, rml, alpha, beta);
+
+ // Write PV to transposition table, in case the relevant entries have
+ // been overwritten during the search.
+ TT.insert_pv(p, ss[0].pv);
+
+ if (AbortSearch)
+ 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);
// Erase the easy move if it differs from the new best move
if (ss[0].pv[0] != EasyMove)
// Time to stop?
bool stopSearch = false;
- // Stop search early if there is only a single legal move:
+ // Stop search early if there is only a single legal move
if (Iteration >= 6 && rml.move_count() == 1)
stopSearch = true;
// Stop search early when the last two iterations returned a mate score
if ( Iteration >= 6
- && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100
- && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100)
+ && abs(IterationInfo[Iteration].value) >= abs(VALUE_MATE) - 100
+ && abs(IterationInfo[Iteration-1].value) >= 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)
ExtraSearchTime = BestMoveChangesByIteration[Iteration] * (MaxSearchTime / 2)
+ BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
- // Try to guess if the current iteration is the last one or the last two
- LastIterations = (current_search_time() > ((MaxSearchTime + ExtraSearchTime)*58) / 128);
-
// 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 (stopSearch)
{
+ //FIXME: Implement fail-low emergency measures
if (!PonderSearch)
break;
else
StopOnPonderhit = true;
}
}
- // Write PV to transposition table, in case the relevant entries have
- // been overwritten during the search:
- TT.insert_pv(p, ss[0].pv);
if (MaxDepth && Iteration >= MaxDepth)
break;
<< " hashfull " << TT.full() << std::endl;
// Print the best move and the ponder move to the standard output
+ if (ss[0].pv[0] == MOVE_NONE)
+ {
+ ss[0].pv[0] = rml.get_move(0);
+ ss[0].pv[1] = MOVE_NONE;
+ }
std::cout << "bestmove " << ss[0].pv[0];
if (ss[0].pv[1] != MOVE_NONE)
std::cout << " ponder " << ss[0].pv[1];
if (dbg_show_hit_rate)
dbg_print_hit_rate(LogFile);
- UndoInfo u;
+ StateInfo st;
LogFile << "Nodes: " << nodes_searched() << std::endl
<< "Nodes/second: " << nps() << std::endl
<< "Best move: " << move_to_san(p, ss[0].pv[0]) << std::endl;
- p.do_move(ss[0].pv[0], u);
+ p.do_move(ss[0].pv[0], st);
LogFile << "Ponder move: " << move_to_san(p, ss[0].pv[1])
<< std::endl << std::endl;
}
// scheme (perhaps we should try to use this at internal PV nodes, too?)
// and prints some information to the standard output.
- Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml) {
+ Value root_search(Position& pos, SearchStack ss[], RootMoveList &rml, Value alpha, Value beta) {
- Value alpha = -VALUE_INFINITE;
- Value beta = VALUE_INFINITE, value;
+ Value oldAlpha = alpha;
+ Value value;
Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move());
// 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;
+ }
int64_t nodes;
Move move;
- UndoInfo u;
+ StateInfo st;
Depth ext, newDepth;
RootMoveNumber = i + 1;
newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
// Make the move, and search it
- pos.do_move(move, u, dcCandidates);
+ pos.do_move(move, st, dcCandidates);
if (i < MultiPV)
{
- value = -search_pv(pos, ss, -beta, VALUE_INFINITE, newDepth, 1, 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);
// 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 <= ValueByIteration[Iteration-1] - ProblemMargin);
+ Problem = (Iteration >= 2 && value <= IterationInfo[Iteration-1].value - ProblemMargin);
if (Problem && StopOnPonderhit)
StopOnPonderhit = false;
}
}
- pos.undo_move(move, u);
+ 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:
+ // move and/or PV.
if (AbortSearch)
break;
rml.set_move_score(i, -VALUE_INFINITE);
else
{
- // New best move!
+ // PV move or new best move!
// Update PV
rml.set_move_score(i, value);
if (i > 0)
BestMoveChangesByIteration[Iteration]++;
- // Print search information to the standard output:
+ // Print search information to the standard output
std::cout << "info depth " << Iteration
<< " score " << value_to_string(value)
<< " time " << current_search_time()
LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, ss[0].pv)
<< std::endl;
- alpha = value;
+ 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 > ValueByIteration[Iteration - 1] - NoProblemMargin)
+ if (value > IterationInfo[Iteration - 1].value - NoProblemMargin)
Problem = false;
}
else // MultiPV > 1
}
alpha = rml.get_move_score(Min(i, MultiPV-1));
}
- }
+ } // New best move case
+
+ assert(alpha >= oldAlpha);
+
+ FailLow = (alpha == oldAlpha);
}
return alpha;
}
// search_pv() is the main search function for PV nodes.
- Value search_pv(Position &pos, SearchStack ss[], Value alpha, Value beta,
+ Value search_pv(Position& pos, SearchStack ss[], Value alpha, Value beta,
Depth depth, int ply, int threadID) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
// Initialize, and make an early exit in case of an aborted search,
// an instant draw, maximum ply reached, etc.
- init_node(pos, ss, ply, threadID);
+ init_node(ss, ply, threadID);
// After init_node() that calls poll()
if (AbortSearch || thread_should_stop(threadID))
// Transposition table lookup. At PV nodes, we don't use the TT for
// pruning, but only for move ordering.
- const TTEntry* tte = TT.retrieve(pos);
+ const TTEntry* tte = TT.retrieve(pos.get_key());
Move ttMove = (tte ? tte->move() : MOVE_NONE);
// Go with internal iterative deepening if we don't have a TT move
// Initialize a MovePicker object for the current position, and prepare
// to search all moves
- MovePicker mp = MovePicker(pos, true, ttMove, ss[ply], depth);
+ MovePicker mp = MovePicker(pos, ttMove, depth, Threads[threadID].H, &ss[ply]);
Move move, movesSearched[256];
int moveCount = 0;
Value value, bestValue = -VALUE_INFINITE;
Bitboard dcCandidates = mp.discovered_check_candidates();
+ Color us = pos.side_to_move();
bool isCheck = pos.is_check();
- bool mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move()));
+ bool mateThreat = pos.has_mate_threat(opposite_color(us));
// Loop through all legal moves until no moves remain or a beta cutoff
// occurs.
assert(move_is_ok(move));
bool singleReply = (isCheck && mp.number_of_moves() == 1);
- bool moveIsCheck = pos.move_is_check(move);
+ bool moveIsCheck = pos.move_is_check(move, dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
movesSearched[moveCount++] = ss[ply].currentMove = move;
- if (moveIsCapture)
- ss[ply].currentMoveCaptureValue =
- move_is_ep(move)? PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move));
- else
- ss[ply].currentMoveCaptureValue = Value(0);
-
// Decide the new search depth
bool dangerous;
Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);
Depth newDepth = depth - OnePly + ext;
// Make and search the move
- UndoInfo u;
- pos.do_move(move, u, dcCandidates);
+ StateInfo st;
+ pos.do_move(move, st, dcCandidates);
if (moveCount == 1) // The first move in list is the PV
value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);
}
}
}
- pos.undo_move(move, u);
+ pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
}
// 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:
+ // (from the computer's point of view) since the previous iteration.
if ( ply == 1
&& Iteration >= 2
- && -value <= ValueByIteration[Iteration-1] - ProblemMargin)
+ && -value <= IterationInfo[Iteration-1].value - ProblemMargin)
Problem = true;
}
}
// All legal moves have been searched. A special case: If there were
- // no legal moves, it must be mate or stalemate:
+ // no legal moves, it must be mate or stalemate.
if (moveCount == 0)
return (isCheck ? value_mated_in(ply) : VALUE_DRAW);
return bestValue;
if (bestValue <= oldAlpha)
- TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_UPPER);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
else if (bestValue >= beta)
{
Move m = ss[ply].pv[ply];
if (ok_to_history(pos, m)) // Only non capture moves are considered
{
- update_history(pos, m, depth, movesSearched, moveCount);
+ update_history(pos, m, depth, Threads[threadID].H, movesSearched, moveCount);
update_killers(m, ss[ply]);
}
- TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m);
}
else
- TT.store(pos, value_to_tt(bestValue, ply), depth, ss[ply].pv[ply], VALUE_TYPE_EXACT);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss[ply].pv[ply]);
return bestValue;
}
// search() is the search function for zero-width nodes.
- Value search(Position &pos, SearchStack ss[], Value beta, Depth depth,
+ Value search(Position& pos, SearchStack ss[], Value beta, Depth depth,
int ply, bool allowNullmove, int threadID) {
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
// Initialize, and make an early exit in case of an aborted search,
// an instant draw, maximum ply reached, etc.
- init_node(pos, ss, ply, threadID);
+ init_node(ss, ply, threadID);
// After init_node() that calls poll()
if (AbortSearch || thread_should_stop(threadID))
return beta - 1;
// Transposition table lookup
- const TTEntry* tte = TT.retrieve(pos);
+ const TTEntry* tte = TT.retrieve(pos.get_key());
Move ttMove = (tte ? tte->move() : MOVE_NONE);
if (tte && ok_to_use_TT(tte, depth, beta, ply))
Value approximateEval = quick_evaluate(pos);
bool mateThreat = false;
- bool nullDrivenIID = false;
bool isCheck = pos.is_check();
// Null move search
{
ss[ply].currentMove = MOVE_NULL;
- UndoInfo u;
- pos.do_null_move(u);
- int R = (depth >= 4 * OnePly ? 4 : 3); // Null move dynamic reduction
+ StateInfo st;
+ pos.do_null_move(st);
+ int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction
Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
- // Check for a null capture artifact, if the value without the null capture
- // is above beta then mark the node as a suspicious failed low. We will verify
- // later if we are really under threat.
- if ( UseNullDrivenIID
- && nullValue < beta
- && depth > 6 * OnePly
- &&!value_is_mate(nullValue)
- && ttMove == MOVE_NONE
- && ss[ply + 1].currentMove != MOVE_NONE
- && pos.move_is_capture(ss[ply + 1].currentMove)
- && pos.see(ss[ply + 1].currentMove) + nullValue >= beta)
- nullDrivenIID = true;
-
- pos.undo_null_move(u);
+ pos.undo_null_move();
if (value_is_mate(nullValue))
{
// low score (which will cause the reduced move to fail high in the
// parent node, which will trigger a re-search with full depth).
if (nullValue == value_mated_in(ply + 2))
- {
mateThreat = true;
- nullDrivenIID = false;
- }
+
ss[ply].threatMove = ss[ply + 1].currentMove;
if ( depth < ThreatDepth
&& ss[ply - 1].reduction
}
// Null move search not allowed, try razoring
else if ( !value_is_mate(beta)
- && approximateEval < beta - RazorMargin
&& depth < RazorDepth
- && (RazorAtDepthOne || depth > OnePly)
+ && approximateEval < beta - RazorApprMargins[int(depth) - 2]
+ && ss[ply - 1].currentMove != MOVE_NULL
&& ttMove == MOVE_NONE
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
- if ( (v < beta - RazorMargin - RazorMargin / 4)
- || (depth < 3*OnePly && v < beta - RazorMargin)
- || (depth < 2*OnePly && v < beta - RazorMargin / 2))
- return v;
+ if (v < beta - RazorMargins[int(depth) - 2])
+ return v;
}
// Go with internal iterative deepening if we don't have a TT move
search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID);
ttMove = ss[ply].pv[ply];
}
- else if (nullDrivenIID)
- {
- // The null move failed low due to a suspicious capture. Perhaps we
- // are facing a null capture artifact due to the side to move change
- // and this position should fail high. So do a normal search with a
- // reduced depth to get a good ttMove to use in the following full
- // depth search.
- Move tm = ss[ply].threatMove;
-
- assert(tm != MOVE_NONE);
- assert(ttMove == MOVE_NONE);
-
- search(pos, ss, beta, depth/2, ply, false, threadID);
- ttMove = ss[ply].pv[ply];
- ss[ply].threatMove = tm;
- }
// Initialize a MovePicker object for the current position, and prepare
- // to search all moves:
- MovePicker mp = MovePicker(pos, false, ttMove, ss[ply], depth);
+ // to search all moves.
+ MovePicker mp = MovePicker(pos, ttMove, depth, Threads[threadID].H, &ss[ply]);
Move move, movesSearched[256];
int moveCount = 0;
Value value, bestValue = -VALUE_INFINITE;
Bitboard dcCandidates = mp.discovered_check_candidates();
Value futilityValue = VALUE_NONE;
- bool useFutilityPruning = UseFutilityPruning
- && depth < SelectiveDepth
+ bool useFutilityPruning = depth < SelectiveDepth
&& !isCheck;
// Loop through all legal moves until no moves remain or a beta cutoff
assert(move_is_ok(move));
bool singleReply = (isCheck && mp.number_of_moves() == 1);
- bool moveIsCheck = pos.move_is_check(move);
+ bool moveIsCheck = pos.move_is_check(move, dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
movesSearched[moveCount++] = ss[ply].currentMove = move;
{
// History pruning. See ok_to_prune() definition
if ( moveCount >= 2 + int(depth)
- && ok_to_prune(pos, move, ss[ply].threatMove, depth))
+ && ok_to_prune(pos, move, ss[ply].threatMove, depth, Threads[threadID].H))
continue;
// Value based pruning
- if (depth < 7 * OnePly && approximateEval < beta)
+ if (approximateEval < beta)
{
if (futilityValue == VALUE_NONE)
futilityValue = evaluate(pos, ei, threadID)
- + FutilityMargins[int(depth)/2 - 1]
- + 32 * (depth & 1);
+ + FutilityMargins[int(depth) - 2];
if (futilityValue < beta)
{
}
// Make and search the move
- UndoInfo u;
- pos.do_move(move, u, dcCandidates);
+ StateInfo st;
+ pos.do_move(move, st, dcCandidates);
// 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.
ss[ply].reduction = Depth(0);
value = -search(pos, ss, -(beta-1), newDepth, ply+1, true, threadID);
}
- pos.undo_move(move, u);
+ pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
return bestValue;
if (bestValue < beta)
- TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_UPPER);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
else
{
BetaCounter.add(pos.side_to_move(), depth, threadID);
Move m = ss[ply].pv[ply];
if (ok_to_history(pos, m)) // Only non capture moves are considered
{
- update_history(pos, m, depth, movesSearched, moveCount);
+ update_history(pos, m, depth, Threads[threadID].H, movesSearched, moveCount);
update_killers(m, ss[ply]);
}
- TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m);
}
+
+ assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
+
return bestValue;
}
// search function when the remaining depth is zero (or, to be more precise,
// less than OnePly).
- Value qsearch(Position &pos, SearchStack ss[], Value alpha, Value beta,
+ Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta,
Depth depth, int ply, int threadID) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
// Initialize, and make an early exit in case of an aborted search,
// an instant draw, maximum ply reached, etc.
- init_node(pos, ss, ply, threadID);
+ init_node(ss, ply, threadID);
// After init_node() that calls poll()
if (AbortSearch || thread_should_stop(threadID))
if (pos.is_draw())
return VALUE_DRAW;
- // Transposition table lookup
- const TTEntry* tte = TT.retrieve(pos);
- if (tte && ok_to_use_TT(tte, depth, beta, ply))
- return value_from_tt(tte->value(), ply);
+ // Transposition table lookup, only when not in PV
+ TTEntry* tte = NULL;
+ bool pvNode = (beta - alpha != 1);
+ if (!pvNode)
+ {
+ tte = TT.retrieve(pos.get_key());
+ if (tte && ok_to_use_TT(tte, depth, beta, ply))
+ {
+ assert(tte->type() != VALUE_TYPE_EVAL);
+
+ return value_from_tt(tte->value(), ply);
+ }
+ }
+ Move ttMove = (tte ? tte->move() : MOVE_NONE);
// Evaluate the position statically
EvalInfo ei;
+ Value staticValue;
bool isCheck = pos.is_check();
- Value staticValue = (isCheck ? -VALUE_INFINITE : evaluate(pos, ei, threadID));
+ ei.futilityMargin = Value(0); // Manually initialize futilityMargin
+
+ if (isCheck)
+ staticValue = -VALUE_INFINITE;
+
+ else if (tte && tte->type() == VALUE_TYPE_EVAL)
+ {
+ // Use the cached evaluation score if possible
+ assert(tte->value() == evaluate(pos, ei, threadID));
+ assert(ei.futilityMargin == Value(0));
+
+ staticValue = tte->value();
+ }
+ else
+ staticValue = evaluate(pos, ei, threadID);
if (ply == PLY_MAX - 1)
return evaluate(pos, ei, threadID);
Value bestValue = staticValue;
if (bestValue >= beta)
+ {
+ // Store the score to avoid a future costly evaluation() call
+ if (!isCheck && !tte && ei.futilityMargin == 0)
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EVAL, Depth(-127*OnePly), MOVE_NONE);
+
return bestValue;
+ }
if (bestValue > alpha)
alpha = bestValue;
// 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.
- bool pvNode = (beta - alpha != 1);
- MovePicker mp = MovePicker(pos, pvNode, MOVE_NONE, EmptySearchStack, depth, isCheck ? NULL : &ei);
+ MovePicker mp = MovePicker(pos, ttMove, depth, Threads[threadID].H);
Move move;
int moveCount = 0;
Bitboard dcCandidates = mp.discovered_check_candidates();
- bool enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
+ Color us = pos.side_to_move();
+ bool enoughMaterial = pos.non_pawn_material(us) > RookValueMidgame;
// Loop through the moves until no moves remain or a beta cutoff
// occurs.
ss[ply].currentMove = move;
// Futility pruning
- if ( UseQSearchFutilityPruning
- && enoughMaterial
+ if ( enoughMaterial
&& !isCheck
&& !pvNode
&& !move_promotion(move)
- && !pos.move_is_check(move)
+ && !pos.move_is_check(move, dcCandidates)
&& !pos.move_is_passed_pawn_push(move))
{
Value futilityValue = staticValue
continue;
// Make and search the move.
- UndoInfo u;
- pos.do_move(move, u, dcCandidates);
+ StateInfo st;
+ pos.do_move(move, st, dcCandidates);
Value value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
- pos.undo_move(move, u);
+ pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
}
// All legal moves have been searched. A special case: If we're in check
- // and no legal moves were found, it is checkmate:
+ // and no legal moves were found, it is checkmate.
if (pos.is_check() && moveCount == 0) // Mate!
return value_mated_in(ply);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
// Update transposition table
- TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_EXACT);
+ Move m = ss[ply].pv[ply];
+ if (!pvNode)
+ {
+ Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
+ if (bestValue < beta)
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, d, MOVE_NONE);
+ else
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, m);
+ }
// Update killers only for good check moves
- Move m = ss[ply].currentMove;
if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered
- {
- // Wrong to update history when depth is <= 0
update_killers(m, ss[ply]);
- }
+
return bestValue;
}
// also don't need to store anything to the hash table here: This is taken
// care of after we return from the split point.
- void sp_search(SplitPoint *sp, int threadID) {
+ void sp_search(SplitPoint* sp, int threadID) {
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
Position pos = Position(sp->pos);
- SearchStack *ss = sp->sstack[threadID];
+ SearchStack* ss = sp->sstack[threadID];
Value value;
Move move;
bool isCheck = pos.is_check();
- bool useFutilityPruning = UseFutilityPruning
- && sp->depth < SelectiveDepth
+ bool useFutilityPruning = sp->depth < SelectiveDepth
&& !isCheck;
while ( sp->bestValue < sp->beta
&& (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
{
assert(move_is_ok(move));
- assert(pos.discovered_check_candidates(pos.side_to_move()) == sp->dcCandidates);
- bool moveIsCheck = pos.move_is_check(move);
+ bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
lock_grab(&(sp->lock));
&& !moveIsCapture
&& !move_promotion(move)
&& moveCount >= 2 + int(sp->depth)
- && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth))
+ && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth, Threads[threadID].H))
continue;
// Make and search the move.
- UndoInfo u;
- pos.do_move(move, u, sp->dcCandidates);
+ StateInfo st;
+ pos.do_move(move, st, sp->dcCandidates);
// 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.
ss[sp->ply].reduction = Depth(0);
value = -search(pos, ss, -(sp->beta - 1), newDepth, sp->ply+1, true, threadID);
}
- pos.undo_move(move, u);
+ pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
lock_grab(&(sp->lock));
// 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:
+ // a beta cutoff higher up in the tree, stop all slave threads.
if (sp->master == threadID && thread_should_stop(threadID))
for (int i = 0; i < ActiveThreads; i++)
if (sp->slaves[i])
// the normal search_pv() function, but simpler. Because we have already
// probed the hash table and searched the first move before splitting, we
// don't have to repeat all this work in sp_search_pv(). We also don't
- // need to store anything to the hash table here: This is taken care of
+ // need to store anything to the hash table here: This is taken care of
// after we return from the split point.
- void sp_search_pv(SplitPoint *sp, int threadID) {
+ void sp_search_pv(SplitPoint* sp, int threadID) {
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
Position pos = Position(sp->pos);
- SearchStack *ss = sp->sstack[threadID];
+ SearchStack* ss = sp->sstack[threadID];
Value value;
Move move;
&& !thread_should_stop(threadID)
&& (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
{
- assert(pos.discovered_check_candidates(pos.side_to_move()) == sp->dcCandidates);
-
- bool moveIsCheck = pos.move_is_check(move);
+ bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
assert(move_is_ok(move));
- if (moveIsCapture)
- ss[sp->ply].currentMoveCaptureValue =
- move_is_ep(move)? PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move));
- else
- ss[sp->ply].currentMoveCaptureValue = Value(0);
-
lock_grab(&(sp->lock));
int moveCount = ++sp->moves;
lock_release(&(sp->lock));
Depth newDepth = sp->depth - OnePly + ext;
// Make and search the move.
- UndoInfo u;
- pos.do_move(move, u, sp->dcCandidates);
+ StateInfo st;
+ pos.do_move(move, st, sp->dcCandidates);
// 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.
{
// 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
+ // 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 = false;
}
}
- pos.undo_move(move, u);
+ pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
if (value == value_mate_in(sp->ply + 1))
ss[sp->ply].mateKiller = move;
- if(value >= sp->beta)
+ if (value >= sp->beta)
{
- for(int i = 0; i < ActiveThreads; i++)
- if(i != threadID && (i == sp->master || sp->slaves[i]))
+ for (int i = 0; i < ActiveThreads; i++)
+ if (i != threadID && (i == sp->master || sp->slaves[i]))
Threads[i].stop = true;
sp->finished = true;
// (from the computer's point of view) since the previous iteration.
if ( sp->ply == 1
&& Iteration >= 2
- && -value <= ValueByIteration[Iteration-1] - ProblemMargin)
+ && -value <= IterationInfo[Iteration-1].value - ProblemMargin)
Problem = true;
}
lock_release(&(sp->lock));
void BetaCounterType::clear() {
for (int i = 0; i < THREAD_MAX; i++)
- hits[i][WHITE] = hits[i][BLACK] = 0ULL;
+ Threads[i].betaCutOffs[WHITE] = Threads[i].betaCutOffs[BLACK] = 0ULL;
}
void BetaCounterType::add(Color us, Depth d, int threadID) {
// Weighted count based on depth
- hits[threadID][us] += int(d);
+ Threads[threadID].betaCutOffs[us] += unsigned(d);
}
void BetaCounterType::read(Color us, int64_t& our, int64_t& their) {
our = their = 0UL;
for (int i = 0; i < THREAD_MAX; i++)
{
- our += hits[i][us];
- their += hits[i][opposite_color(us)];
+ our += Threads[i].betaCutOffs[us];
+ their += Threads[i].betaCutOffs[opposite_color(us)];
}
}
// Constructor
RootMove::RootMove() {
- nodes = cumulativeNodes = 0ULL;
+ nodes = cumulativeNodes = ourBeta = theirBeta = 0ULL;
}
// RootMove::operator<() is the comparison function used when
for (int k = 0; !includeMove && searchMoves[k] != MOVE_NONE; k++)
includeMove = (searchMoves[k] == mlist[i].move);
- if (includeMove)
- {
- // Find a quick score for the move
- UndoInfo u;
- SearchStack ss[PLY_MAX_PLUS_2];
-
- moves[count].move = mlist[i].move;
- moves[count].nodes = 0ULL;
- pos.do_move(moves[count].move, u);
- moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE,
- Depth(0), 1, 0);
- pos.undo_move(moves[count].move, u);
- moves[count].pv[0] = moves[i].move;
- moves[count].pv[1] = MOVE_NONE; // FIXME
- count++;
- }
+ if (!includeMove)
+ continue;
+
+ // Find a quick score for the move
+ StateInfo st;
+ SearchStack ss[PLY_MAX_PLUS_2];
+
+ moves[count].move = mlist[i].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[1] = MOVE_NONE; // FIXME
+ count++;
}
sort();
}
}
- // init_search_stack() initializes a search stack at the beginning of a
- // new search from the root.
- void init_search_stack(SearchStack& ss) {
-
- ss.pv[0] = MOVE_NONE;
- ss.pv[1] = MOVE_NONE;
- ss.currentMove = MOVE_NONE;
- ss.threatMove = MOVE_NONE;
- ss.reduction = Depth(0);
- for (int j = 0; j < KILLER_MAX; j++)
- ss.killers[j] = MOVE_NONE;
- }
-
- void init_search_stack(SearchStack ss[]) {
-
- for (int i = 0; i < 3; i++)
- {
- ss[i].pv[i] = MOVE_NONE;
- ss[i].pv[i+1] = MOVE_NONE;
- ss[i].currentMove = MOVE_NONE;
- ss[i].threatMove = MOVE_NONE;
- ss[i].reduction = Depth(0);
- for (int j = 0; j < KILLER_MAX; j++)
- ss[i].killers[j] = MOVE_NONE;
- }
- }
-
-
// init_node() is called at the beginning of all the search functions
// (search(), search_pv(), qsearch(), and so on) and initializes the search
// stack object corresponding to the current node. Once every
// NodesBetweenPolls nodes, init_node() also calls poll(), which polls
// for user input and checks whether it is time to stop the search.
- void init_node(const Position &pos, SearchStack ss[], int ply, int threadID) {
+ void init_node(SearchStack ss[], int ply, int threadID) {
+
assert(ply >= 0 && ply < PLY_MAX);
assert(threadID >= 0 && threadID < ActiveThreads);
Threads[threadID].nodes++;
- if(threadID == 0) {
- NodesSincePoll++;
- if(NodesSincePoll >= NodesBetweenPolls) {
- poll();
- NodesSincePoll = 0;
- }
+ if (threadID == 0)
+ {
+ NodesSincePoll++;
+ if (NodesSincePoll >= NodesBetweenPolls)
+ {
+ poll();
+ NodesSincePoll = 0;
+ }
}
- ss[ply].pv[ply] = ss[ply].pv[ply+1] = ss[ply].currentMove = MOVE_NONE;
- ss[ply+2].mateKiller = MOVE_NONE;
- ss[ply].threatMove = MOVE_NONE;
- ss[ply].reduction = Depth(0);
- ss[ply].currentMoveCaptureValue = Value(0);
- for (int j = 0; j < KILLER_MAX; j++)
- ss[ply+2].killers[j] = MOVE_NONE;
+ ss[ply].init(ply);
+ ss[ply+2].initKillers();
- if(Threads[threadID].printCurrentLine)
- print_current_line(ss, ply, threadID);
+ if (Threads[threadID].printCurrentLine)
+ print_current_line(ss, ply, threadID);
}
// difference between the two functions is that sp_update_pv also updates
// the PV at the parent node.
- void sp_update_pv(SearchStack *pss, SearchStack ss[], int ply) {
+ void sp_update_pv(SearchStack* pss, SearchStack ss[], int ply) {
assert(ply >= 0 && ply < PLY_MAX);
ss[ply].pv[ply] = pss[ply].pv[ply] = ss[ply].currentMove;
// assumed to be the move that was made to reach the current position, while
// the second move is assumed to be a move from the current position.
- bool connected_moves(const Position &pos, Move m1, Move m2) {
+ bool connected_moves(const Position& pos, Move m1, Move m2) {
Square f1, t1, f2, t2;
assert(move_is_ok(m1));
assert(move_is_ok(m2));
- if(m2 == MOVE_NONE)
- return false;
+ if (m2 == MOVE_NONE)
+ return false;
- // Case 1: The moving piece is the same in both moves.
+ // Case 1: The moving piece is the same in both moves
f2 = move_from(m2);
t1 = move_to(m1);
- if(f2 == t1)
- return true;
+ if (f2 == t1)
+ return true;
- // Case 2: The destination square for m2 was vacated by m1.
+ // Case 2: The destination square for m2 was vacated by m1
t2 = move_to(m2);
f1 = move_from(m1);
- if(t2 == f1)
- return true;
+ if (t2 == f1)
+ return true;
- // Case 3: Moving through the vacated square:
- if(piece_is_slider(pos.piece_on(f2)) &&
- bit_is_set(squares_between(f2, t2), f1))
+ // Case 3: Moving through the vacated square
+ if ( piece_is_slider(pos.piece_on(f2))
+ && bit_is_set(squares_between(f2, t2), f1))
return true;
- // Case 4: The destination square for m2 is attacked by the moving piece
- // in m1:
- if(pos.piece_attacks_square(pos.piece_on(t1), t1, t2))
- return true;
+ // Case 4: The destination square for m2 is attacked by the moving piece in m1
+ if (pos.piece_attacks_square(pos.piece_on(t1), t1, t2))
+ return true;
- // Case 5: Discovered check, checking piece is the piece moved in m1:
- if(piece_is_slider(pos.piece_on(t1)) &&
- bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())),
- f2) &&
- !bit_is_set(squares_between(t2, pos.king_square(pos.side_to_move())),
- t2)) {
- Bitboard occ = pos.occupied_squares();
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(us);
- clear_bit(&occ, f2);
- if(pos.type_of_piece_on(t1) == BISHOP) {
- if(bit_is_set(bishop_attacks_bb(ksq, occ), t1))
- return true;
- }
- else if(pos.type_of_piece_on(t1) == ROOK) {
- if(bit_is_set(rook_attacks_bb(ksq, occ), t1))
- return true;
- }
- else {
- assert(pos.type_of_piece_on(t1) == QUEEN);
- if(bit_is_set(queen_attacks_bb(ksq, occ), t1))
- return true;
- }
+ // Case 5: Discovered check, checking piece is the piece moved in m1
+ if ( piece_is_slider(pos.piece_on(t1))
+ && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2)
+ && !bit_is_set(squares_between(t2, pos.king_square(pos.side_to_move())), t2))
+ {
+ Bitboard occ = pos.occupied_squares();
+ Color us = pos.side_to_move();
+ Square ksq = pos.king_square(us);
+ clear_bit(&occ, f2);
+ if (pos.type_of_piece_on(t1) == BISHOP)
+ {
+ if (bit_is_set(bishop_attacks_bb(ksq, occ), t1))
+ return true;
+ }
+ else if (pos.type_of_piece_on(t1) == ROOK)
+ {
+ if (bit_is_set(rook_attacks_bb(ksq, occ), t1))
+ return true;
+ }
+ else
+ {
+ assert(pos.type_of_piece_on(t1) == QUEEN);
+ if (bit_is_set(queen_attacks_bb(ksq, occ), t1))
+ return true;
+ }
}
-
return false;
}
// probably a good idea to avoid null moves in at least some more
// complicated endgames, e.g. KQ vs KR. FIXME
- bool ok_to_do_nullmove(const Position &pos) {
- if(pos.non_pawn_material(pos.side_to_move()) == Value(0))
- return false;
- return true;
+ bool ok_to_do_nullmove(const Position& pos) {
+
+ return pos.non_pawn_material(pos.side_to_move()) != Value(0);
}
// non-tactical moves late in the move list close to the leaves are
// candidates for pruning.
- bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d) {
- Square mfrom, mto, tfrom, tto;
+ bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d, const History& H) {
assert(move_is_ok(m));
assert(threat == MOVE_NONE || move_is_ok(threat));
assert(!pos.move_is_passed_pawn_push(m));
assert(d >= OnePly);
+ Square mfrom, mto, tfrom, tto;
+
mfrom = move_from(m);
mto = move_to(m);
tfrom = move_from(threat);
tto = move_to(threat);
- // Case 1: Castling moves are never pruned.
+ // Case 1: Castling moves are never pruned
if (move_is_castle(m))
return false;
&& ( pos.midgame_value_of_piece_on(tfrom) >= pos.midgame_value_of_piece_on(tto)
|| pos.type_of_piece_on(tfrom) == KING)
&& pos.move_attacks_square(m, tto))
- return false;
+ return false;
- // Case 4: Don't prune moves with good history.
- if (!H.ok_to_prune(pos.piece_on(move_from(m)), m, d))
+ // Case 4: Don't prune moves with good history
+ if (!H.ok_to_prune(pos.piece_on(mfrom), mto, d))
return false;
// Case 5: If the moving piece in the threatened move is a slider, don't
&& piece_is_slider(pos.piece_on(tfrom))
&& bit_is_set(squares_between(tfrom, tto), mto)
&& pos.see(m) >= 0)
- return false;
+ return false;
return true;
}
// update_history() registers a good move that produced a beta-cutoff
// in history and marks as failures all the other moves of that ply.
- void update_history(const Position& pos, Move m, Depth depth,
+ void update_history(const Position& pos, Move m, Depth depth, History& H,
Move movesSearched[], int moveCount) {
- H.success(pos.piece_on(move_from(m)), m, depth);
+ H.success(pos.piece_on(move_from(m)), move_to(m), depth);
for (int i = 0; i < moveCount - 1; i++)
{
assert(m != movesSearched[i]);
if (ok_to_history(pos, movesSearched[i]))
- H.failure(pos.piece_on(move_from(movesSearched[i])), movesSearched[i]);
+ H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]));
}
}
// is used for time managment.
bool fail_high_ply_1() {
+
for(int i = 0; i < ActiveThreads; i++)
- if(Threads[i].failHighPly1)
- return true;
+ if (Threads[i].failHighPly1)
+ return true;
+
return false;
}
AbortSearch = true;
PonderSearch = false;
Quit = true;
+ return;
}
- else if(command == "stop")
+ else if (command == "stop")
{
AbortSearch = true;
PonderSearch = false;
}
- else if(command == "ponderhit")
+ else if (command == "ponderhit")
ponderhit();
}
// Print search information
return;
bool overTime = t > AbsoluteMaxSearchTime
- || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime)
- || ( !FailHigh && !fail_high_ply_1() && !Problem
+ || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime && !FailLow) //FIXME: We are not checking any problem flags, BUG?
+ || ( !FailHigh && !FailLow && !fail_high_ply_1() && !Problem
&& t > 6*(MaxSearchTime + ExtraSearchTime));
- if ( (Iteration >= 2 && (!InfiniteSearch && overTime))
+ if ( (Iteration >= 3 && (!InfiniteSearch && overTime))
|| (ExactMaxTime && t >= ExactMaxTime)
|| (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes))
AbortSearch = true;
// it correctly predicted the opponent's move.
void ponderhit() {
+
int t = current_search_time();
PonderSearch = false;
- if(Iteration >= 2 &&
+ if (Iteration >= 3 &&
(!InfiniteSearch && (StopOnPonderhit ||
t > AbsoluteMaxSearchTime ||
(RootMoveNumber == 1 &&
- t > MaxSearchTime + ExtraSearchTime) ||
- (!FailHigh && !fail_high_ply_1() && !Problem &&
+ t > MaxSearchTime + ExtraSearchTime && !FailLow) ||
+ (!FailHigh && !FailLow && !fail_high_ply_1() && !Problem &&
t > 6*(MaxSearchTime + ExtraSearchTime)))))
AbortSearch = true;
}
// thread. Called when the UCI option UCI_ShowCurrLine is 'true'.
void print_current_line(SearchStack ss[], int ply, int threadID) {
+
assert(ply >= 0 && ply < PLY_MAX);
assert(threadID >= 0 && threadID < ActiveThreads);
- if(!Threads[threadID].idle) {
- lock_grab(&IOLock);
- std::cout << "info currline " << (threadID + 1);
- for(int p = 0; p < ply; p++)
- std::cout << " " << ss[p].currentMove;
- std::cout << std::endl;
- lock_release(&IOLock);
+ if (!Threads[threadID].idle)
+ {
+ lock_grab(&IOLock);
+ std::cout << "info currline " << (threadID + 1);
+ for (int p = 0; p < ply; p++)
+ std::cout << " " << ss[p].currentMove;
+
+ std::cout << std::endl;
+ lock_release(&IOLock);
}
Threads[threadID].printCurrentLine = false;
- if(threadID + 1 < ActiveThreads)
- Threads[threadID + 1].printCurrentLine = true;
+ if (threadID + 1 < ActiveThreads)
+ Threads[threadID + 1].printCurrentLine = true;
}
// after which the bestmove and pondermove will be printed (in id_loop()).
void wait_for_stop_or_ponderhit() {
+
std::string command;
- while(true) {
- if(!std::getline(std::cin, command))
- command = "quit";
-
- if(command == "quit") {
- OpeningBook.close();
- stop_threads();
- quit_eval();
- exit(0);
- }
- else if(command == "ponderhit" || command == "stop")
- break;
+ while (true)
+ {
+ if (!std::getline(std::cin, command))
+ command = "quit";
+
+ if (command == "quit")
+ {
+ Quit = true;
+ break;
+ }
+ else if (command == "ponderhit" || command == "stop")
+ break;
}
}
// The parameter "waitSp", if non-NULL, is a pointer to an active SplitPoint
// object for which the current thread is the master.
- void idle_loop(int threadID, SplitPoint *waitSp) {
+ void idle_loop(int threadID, SplitPoint* waitSp) {
assert(threadID >= 0 && threadID < THREAD_MAX);
Threads[threadID].running = true;
#endif
}
- // If this thread has been assigned work, launch a search:
+ // If this thread has been assigned work, launch a search
if(Threads[threadID].workIsWaiting) {
Threads[threadID].workIsWaiting = false;
if(Threads[threadID].splitPoint->pvNode)
}
// If this thread is the master of a split point and all threads have
- // finished their work at this split point, return from the idle loop:
+ // finished their work at this split point, return from the idle loop.
if(waitSp != NULL && waitSp->cpus == 0)
return;
}
bool thread_should_stop(int threadID) {
assert(threadID >= 0 && threadID < ActiveThreads);
- SplitPoint *sp;
+ SplitPoint* sp;
if(Threads[threadID].stop)
return true;
// threads have returned from sp_search_pv (or, equivalently, when
// splitPoint->cpus becomes 0), split() returns true.
- bool split(const Position &p, SearchStack *sstck, int ply,
- Value *alpha, Value *beta, Value *bestValue,
- Depth depth, int *moves,
- MovePicker *mp, Bitboard dcCandidates, int master, bool pvNode) {
+ bool split(const Position& p, SearchStack* sstck, int ply,
+ Value* alpha, Value* beta, Value* bestValue, Depth depth, int* moves,
+ MovePicker* mp, Bitboard dcCandidates, int master, bool pvNode) {
+
assert(p.is_ok());
assert(sstck != NULL);
assert(ply >= 0 && ply < PLY_MAX);
assert(master >= 0 && master < ActiveThreads);
assert(ActiveThreads > 1);
- SplitPoint *splitPoint;
+ SplitPoint* splitPoint;
int i;
lock_grab(&MPLock);
// If no other thread is available to help us, or if we have too many
- // active split points, don't split:
+ // active split points, don't split.
if(!idle_thread_exists(master) ||
Threads[master].activeSplitPoints >= MaxActiveSplitPoints) {
lock_release(&MPLock);
return false;
}
- // Pick the next available split point object from the split point stack:
+ // Pick the next available split point object from the split point stack
splitPoint = SplitPointStack[master] + Threads[master].activeSplitPoints;
Threads[master].activeSplitPoints++;
- // Initialize the split point object:
+ // Initialize the split point object
splitPoint->parent = Threads[master].splitPoint;
splitPoint->finished = false;
splitPoint->ply = ply;
for(i = 0; i < ActiveThreads; i++)
splitPoint->slaves[i] = 0;
- // Copy the current position and the search stack to the master thread:
+ // Copy the current position and the search stack to the master thread
memcpy(splitPoint->sstack[master], sstck, (ply+1)*sizeof(SearchStack));
Threads[master].splitPoint = splitPoint;
- // Make copies of the current position and search stack for each thread:
+ // Make copies of the current position and search stack for each thread
for(i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint;
i++)
if(thread_is_available(i, master)) {
idle_loop(master, splitPoint);
// We have returned from the idle loop, which means that all threads are
- // finished. Update alpha, beta and bestvalue, and return:
+ // finished. Update alpha, beta and bestvalue, and return.
lock_grab(&MPLock);
if(pvNode) *alpha = splitPoint->alpha;
*beta = splitPoint->beta;
projects / stockfish / blobdiff