#include <iostream>
#include <sstream>
-#include "book.h"
#include "evaluate.h"
#include "movegen.h"
#include "movepick.h"
#include "notation.h"
+#include "rkiss.h"
#include "search.h"
#include "timeman.h"
#include "thread.h"
LimitsType Limits;
std::vector<RootMove> RootMoves;
Position RootPos;
- Color RootColor;
Time::point SearchTime;
StateStackPtr SetupStates;
}
namespace {
- // Set to true to force running with one thread. Used for debugging
- const bool FakeSplit = false;
-
// Different node types, used as template parameter
enum NodeType { Root, PV, NonPV };
return (Depth) Reductions[PvNode][i][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
}
- size_t MultiPV, PVIdx;
+ size_t PVIdx;
TimeManager TimeMgr;
double BestMoveChanges;
Value DrawValue[COLOR_NB];
void id_loop(Position& pos);
Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
- void update_stats(Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt);
+ void update_stats(const Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt);
string uci_pv(const Position& pos, int depth, Value alpha, Value beta);
struct Skill {
- Skill(int l) : level(l), best(MOVE_NONE) {}
+ Skill(int l, int rootSize) : level(l),
+ candidates(l < 20 ? std::min(4, rootSize) : 0),
+ best(MOVE_NONE) {}
~Skill() {
- if (enabled()) // Swap best PV line with the sub-optimal one
+ if (candidates) // Swap best PV line with the sub-optimal one
std::swap(RootMoves[0], *std::find(RootMoves.begin(),
RootMoves.end(), best ? best : pick_move()));
}
- bool enabled() const { return level < 20; }
+ size_t candidates_size() const { return candidates; }
bool time_to_pick(int depth) const { return depth == 1 + level; }
Move pick_move();
int level;
+ size_t candidates;
Move best;
};
void Search::think() {
- static PolyglotBook book; // Defined static to initialize the PRNG only once
-
- RootColor = RootPos.side_to_move();
- TimeMgr.init(Limits, RootPos.game_ply(), RootColor);
+ TimeMgr.init(Limits, RootPos.game_ply(), RootPos.side_to_move());
int cf = Options["Contempt Factor"] * PawnValueEg / 100; // From centipawns
- DrawValue[ RootColor] = VALUE_DRAW - Value(cf);
- DrawValue[~RootColor] = VALUE_DRAW + Value(cf);
+ DrawValue[ RootPos.side_to_move()] = VALUE_DRAW - Value(cf);
+ DrawValue[~RootPos.side_to_move()] = VALUE_DRAW + Value(cf);
if (RootMoves.empty())
{
goto finalize;
}
- if (Options["OwnBook"] && !Limits.infinite && !Limits.mate)
- {
- Move bookMove = book.probe(RootPos, Options["Book File"], Options["Best Book Move"]);
-
- if (bookMove && std::count(RootMoves.begin(), RootMoves.end(), bookMove))
- {
- std::swap(RootMoves[0], *std::find(RootMoves.begin(), RootMoves.end(), bookMove));
- goto finalize;
- }
- }
-
if (Options["Write Search Log"])
{
Log log(Options["Search Log Filename"]);
log << "\nSearching: " << RootPos.fen()
<< "\ninfinite: " << Limits.infinite
<< " ponder: " << Limits.ponder
- << " time: " << Limits.time[RootColor]
- << " increment: " << Limits.inc[RootColor]
+ << " time: " << Limits.time[RootPos.side_to_move()]
+ << " increment: " << Limits.inc[RootPos.side_to_move()]
<< " moves to go: " << Limits.movestogo
<< "\n" << std::endl;
}
for (size_t i = 0; i < Threads.size(); ++i)
Threads[i]->maxPly = 0;
- Threads.sleepWhileIdle = Options["Idle Threads Sleep"];
Threads.timer->run = true;
Threads.timer->notify_one(); // Wake up the recurring timer
id_loop(RootPos); // Let's start searching !
Threads.timer->run = false; // Stop the timer
- Threads.sleepWhileIdle = true; // Send idle threads to sleep
if (Options["Write Search Log"])
{
Value bestValue, alpha, beta, delta;
std::memset(ss-2, 0, 5 * sizeof(Stack));
- (ss-1)->currentMove = MOVE_NULL; // Hack to skip update gains
depth = 0;
BestMoveChanges = 0;
Countermoves.clear();
Followupmoves.clear();
- MultiPV = Options["MultiPV"];
- Skill skill(Options["Skill Level"]);
+ size_t multiPV = Options["MultiPV"];
+ Skill skill(Options["Skill Level"], RootMoves.size());
// Do we have to play with skill handicap? In this case enable MultiPV search
// that we will use behind the scenes to retrieve a set of possible moves.
- if (skill.enabled() && MultiPV < 4)
- MultiPV = 4;
-
- MultiPV = std::min(MultiPV, RootMoves.size());
+ multiPV = std::max(multiPV, skill.candidates_size());
// Iterative deepening loop until requested to stop or target depth reached
while (++depth <= MAX_PLY && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
RootMoves[i].prevScore = RootMoves[i].score;
// MultiPV loop. We perform a full root search for each PV line
- for (PVIdx = 0; PVIdx < MultiPV && !Signals.stop; ++PVIdx)
+ for (PVIdx = 0; PVIdx < multiPV && PVIdx < RootMoves.size() && !Signals.stop; ++PVIdx)
{
// Reset aspiration window starting size
if (depth >= 5)
// Sort the PV lines searched so far and update the GUI
std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
- if (PVIdx + 1 == MultiPV || Time::now() - SearchTime > 3000)
+ if (PVIdx + 1 == multiPV || Time::now() - SearchTime > 3000)
sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
}
// If skill levels are enabled and time is up, pick a sub-optimal best move
- if (skill.enabled() && skill.time_to_pick(depth))
+ if (skill.candidates_size() && skill.time_to_pick(depth))
skill.pick_move();
if (Options["Write Search Log"])
if (Limits.use_time_management() && !Signals.stop && !Signals.stopOnPonderhit)
{
// Take some extra time if the best move has changed
- if (depth > 4 && depth < 50 && MultiPV == 1)
+ if (depth > 4 && multiPV == 1)
TimeMgr.pv_instability(BestMoveChanges);
// Stop the search if only one legal move is available or all
}
else
{
- eval = ss->staticEval = evaluate(pos);
+ eval = ss->staticEval =
+ (ss-1)->currentMove != MOVE_NULL ? evaluate(pos) : -(ss-1)->staticEval + 2 * Eval::Tempo;
+
TT.store(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, ss->staticEval);
}
&& ss->staticEval != VALUE_NONE
&& (ss-1)->staticEval != VALUE_NONE
&& (move = (ss-1)->currentMove) != MOVE_NULL
+ && move != MOVE_NONE
&& type_of(move) == NORMAL)
{
Square to = to_sq(move);
&& depth < 4 * ONE_PLY
&& eval + razor_margin(depth) <= alpha
&& ttMove == MOVE_NONE
- && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& !pos.pawn_on_7th(pos.side_to_move()))
{
+ if ( depth <= ONE_PLY
+ && eval + razor_margin(3 * ONE_PLY) <= alpha)
+ return qsearch<NonPV, false>(pos, ss, alpha, beta, DEPTH_ZERO);
+
Value ralpha = alpha - razor_margin(depth);
Value v = qsearch<NonPV, false>(pos, ss, ralpha, ralpha+1, DEPTH_ZERO);
if (v <= ralpha)
&& !ss->skipNullMove
&& depth >= 2 * ONE_PLY
&& eval >= beta
- && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move()))
{
ss->currentMove = MOVE_NULL;
// Null move dynamic reduction based on depth and value
Depth R = 3 * ONE_PLY
+ depth / 4
- + int(eval - beta) / PawnValueMg * ONE_PLY;
+ + (abs(beta) < VALUE_KNOWN_WIN ? int(eval - beta) / PawnValueMg * ONE_PLY
+ : DEPTH_ZERO);
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
if (nullValue >= VALUE_MATE_IN_MAX_PLY)
nullValue = beta;
- if (depth < 12 * ONE_PLY)
+ if (depth < 12 * ONE_PLY && abs(beta) < VALUE_KNOWN_WIN)
return nullValue;
// Do verification search at high depths
singularExtensionNode = !RootNode
&& !SpNode
&& depth >= 8 * ONE_PLY
+ && abs(beta) < VALUE_KNOWN_WIN
&& ttMove != MOVE_NONE
+ /* && ttValue != VALUE_NONE Already implicit in the next condition */
+ && abs(ttValue) < VALUE_KNOWN_WIN
&& !excludedMove // Recursive singular search is not allowed
&& (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3 * ONE_PLY;
if ( singularExtensionNode
&& move == ttMove
&& !ext
- && pos.legal(move, ci.pinned)
- && abs(ttValue) < VALUE_KNOWN_WIN)
+ && pos.legal(move, ci.pinned))
{
- assert(ttValue != VALUE_NONE);
-
Value rBeta = ttValue - int(depth);
ss->excludedMove = move;
ss->skipNullMove = true;
if (move == countermoves[0] || move == countermoves[1])
ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY);
+ // Decrease reduction for moves that escape a capture
+ if ( ss->reduction
+ && type_of(move) == NORMAL
+ && type_of(pos.piece_on(to_sq(move))) != PAWN
+ && pos.see(make_move(to_sq(move), from_sq(move))) < 0)
+ ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY);
+
Depth d = std::max(newDepth - ss->reduction, ONE_PLY);
if (SpNode)
alpha = splitPoint->alpha;
value = -search<NonPV, false>(pos, ss+1, -(alpha+1), -alpha, d, true);
- // Research at intermediate depth if reduction is very high
+ // Re-search at intermediate depth if reduction is very high
if (value > alpha && ss->reduction >= 4 * ONE_PLY)
{
Depth d2 = std::max(newDepth - 2 * ONE_PLY, ONE_PLY);
{
assert(bestValue > -VALUE_INFINITE && bestValue < beta);
- thisThread->split<FakeSplit>(pos, ss, alpha, beta, &bestValue, &bestMove,
- depth, moveCount, &mp, NT, cutNode);
+ thisThread->split(pos, ss, alpha, beta, &bestValue, &bestMove,
+ depth, moveCount, &mp, NT, cutNode);
if (Signals.stop || thisThread->cutoff_occurred())
return VALUE_ZERO;
// must be mate or stalemate. If we are in a singular extension search then
// return a fail low score.
if (!moveCount)
- return excludedMove ? alpha
- : inCheck ? mated_in(ss->ply) : DrawValue[pos.side_to_move()];
+ bestValue = excludedMove ? alpha
+ : inCheck ? mated_in(ss->ply) : DrawValue[pos.side_to_move()];
+
+ // Quiet best move: update killers, history, countermoves and followupmoves
+ else if (bestValue >= beta && !pos.capture_or_promotion(bestMove) && !inCheck)
+ update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount - 1);
TT.store(posKey, value_to_tt(bestValue, ss->ply),
bestValue >= beta ? BOUND_LOWER :
PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
depth, bestMove, ss->staticEval);
- // Quiet best move: update killers, history, countermoves and followupmoves
- if (bestValue >= beta && !pos.capture_or_promotion(bestMove) && !inCheck)
- update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount - 1);
-
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
return bestValue;
bestValue = ttValue;
}
else
- ss->staticEval = bestValue = evaluate(pos);
+ ss->staticEval = bestValue =
+ (ss-1)->currentMove != MOVE_NULL ? evaluate(pos) : -(ss-1)->staticEval + 2 * Eval::Tempo;
// Stand pat. Return immediately if static value is at least beta
if (bestValue >= beta)
// update_stats() updates killers, history, countermoves and followupmoves stats after a fail-high
// of a quiet move.
- void update_stats(Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt) {
+ void update_stats(const Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt) {
if (ss->killers[0] != move)
{
}
- // When playing with a strength handicap, choose best move among the MultiPV
- // set using a statistical rule dependent on 'level'. Idea by Heinz van Saanen.
+ // When playing with a strength handicap, choose best move among the first 'candidates'
+ // RootMoves using a statistical rule dependent on 'level'. Idea by Heinz van Saanen.
Move Skill::pick_move() {
rk.rand<unsigned>();
// RootMoves are already sorted by score in descending order
- int variance = std::min(RootMoves[0].score - RootMoves[MultiPV - 1].score, PawnValueMg);
+ int variance = std::min(RootMoves[0].score - RootMoves[candidates - 1].score, PawnValueMg);
int weakness = 120 - 2 * level;
int max_s = -VALUE_INFINITE;
best = MOVE_NONE;
// Choose best move. For each move score we add two terms both dependent on
// weakness. One deterministic and bigger for weaker moves, and one random,
// then we choose the move with the resulting highest score.
- for (size_t i = 0; i < MultiPV; ++i)
+ for (size_t i = 0; i < candidates; ++i)
{
int s = RootMoves[i].score;
// Don't allow crazy blunders even at very low skills
- if (i > 0 && RootMoves[i-1].score > s + 2 * PawnValueMg)
+ if (i > 0 && RootMoves[i - 1].score > s + 2 * PawnValueMg)
break;
// This is our magic formula
StateInfo state[MAX_PLY_PLUS_6], *st = state;
const TTEntry* tte;
- int ply = 0;
- Move m = pv[0];
+ int ply = 1; // At root ply is 1...
+ Move m = pv[0]; // ...instead pv[] array starts from 0
+ Value expectedScore = score;
pv.clear();
do {
pv.push_back(m);
- assert(MoveList<LEGAL>(pos).contains(pv[ply]));
+ assert(MoveList<LEGAL>(pos).contains(pv[ply - 1]));
- pos.do_move(pv[ply++], *st++);
+ pos.do_move(pv[ply++ - 1], *st++);
tte = TT.probe(pos.key());
+ expectedScore = -expectedScore;
} while ( tte
+ && expectedScore == value_from_tt(tte->value(), ply)
&& pos.pseudo_legal(m = tte->move()) // Local copy, TT could change
&& pos.legal(m, pos.pinned_pieces(pos.side_to_move()))
&& ply < MAX_PLY
- && (!pos.is_draw() || ply < 2));
+ && (!pos.is_draw() || ply <= 2));
pv.push_back(MOVE_NONE); // Must be zero-terminating
- while (ply) pos.undo_move(pv[--ply]);
+ while (--ply) pos.undo_move(pv[ply - 1]);
}
StateInfo state[MAX_PLY_PLUS_6], *st = state;
const TTEntry* tte;
- int ply = 0;
+ int idx = 0; // Ply starts from 1, we need to start from 0
do {
tte = TT.probe(pos.key());
- if (!tte || tte->move() != pv[ply]) // Don't overwrite correct entries
- TT.store(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[ply], VALUE_NONE);
+ if (!tte || tte->move() != pv[idx]) // Don't overwrite correct entries
+ TT.store(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[idx], VALUE_NONE);
- assert(MoveList<LEGAL>(pos).contains(pv[ply]));
+ assert(MoveList<LEGAL>(pos).contains(pv[idx]));
- pos.do_move(pv[ply++], *st++);
+ pos.do_move(pv[idx++], *st++);
- } while (pv[ply] != MOVE_NONE);
+ } while (pv[idx] != MOVE_NONE);
- while (ply) pos.undo_move(pv[--ply]);
+ while (idx) pos.undo_move(pv[--idx]);
}
{
// If we are not searching, wait for a condition to be signaled instead of
// wasting CPU time polling for work.
- while ((!searching && Threads.sleepWhileIdle) || exit)
+ while (!searching || exit)
{
if (exit)
{
// Wake up the master thread so to allow it to return from the idle
// loop in case we are the last slave of the split point.
- if ( Threads.sleepWhileIdle
- && this != sp->masterThread
+ if ( this != sp->masterThread
&& sp->slavesMask.none())
{
assert(!sp->masterThread->searching);
// After releasing the lock we can't access any SplitPoint related data
// in a safe way because it could have been released under our feet by
- // the sp master. Also accessing other Thread objects is unsafe because
- // if we are exiting there is a chance that they are already freed.
+ // the sp master.
sp->mutex.unlock();
// Try to late join to another split point if none of its slaves has
if (Threads.size() > 2)
for (size_t i = 0; i < Threads.size(); ++i)
{
- int size = Threads[i]->splitPointsSize; // Local copy
+ const int size = Threads[i]->splitPointsSize; // Local copy
sp = size ? &Threads[i]->splitPoints[size - 1] : NULL;
if ( sp
projects / stockfish / blobdiff