#include <algorithm>
#include <cassert>
-#include <cfloat>
#include <cmath>
#include <cstring>
#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];
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, size_t rootSize) : level(l),
+ candidates(l < 20 ? std::min(4, (int)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;
};
/// Search::perft() is our utility to verify move generation. All the leaf nodes
/// up to the given depth are generated and counted and the sum returned.
-
-static uint64_t perft(Position& pos, Depth depth) {
+template<bool Root>
+uint64_t Search::perft(Position& pos, Depth depth) {
StateInfo st;
- uint64_t cnt = 0;
+ uint64_t cnt, nodes = 0;
CheckInfo ci(pos);
const bool leaf = depth == 2 * ONE_PLY;
for (MoveList<LEGAL> it(pos); *it; ++it)
{
- pos.do_move(*it, st, ci, pos.gives_check(*it, ci));
- cnt += leaf ? MoveList<LEGAL>(pos).size() : ::perft(pos, depth - ONE_PLY);
- pos.undo_move(*it);
+ if (Root && depth <= ONE_PLY)
+ cnt = 1, nodes++;
+ else
+ {
+ pos.do_move(*it, st, ci, pos.gives_check(*it, ci));
+ cnt = leaf ? MoveList<LEGAL>(pos).size() : perft<false>(pos, depth - ONE_PLY);
+ nodes += cnt;
+ pos.undo_move(*it);
+ }
+ if (Root)
+ sync_cout << move_to_uci(*it, pos.is_chess960()) << ": " << cnt << sync_endl;
}
- return cnt;
+ return nodes;
}
-uint64_t Search::perft(Position& pos, Depth depth) {
- return depth > ONE_PLY ? ::perft(pos, depth) : MoveList<LEGAL>(pos).size();
-}
+template uint64_t Search::perft<true>(Position& pos, Depth depth);
+
/// Search::think() is the external interface to Stockfish's search, and is
/// called by the main thread when the program receives the UCI 'go' command. It
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]
- << " moves to go: " << Limits.movestogo
- << "\n" << std::endl;
- }
-
// Reset the threads, still sleeping: will wake up at split time
for (size_t i = 0; i < Threads.size(); ++i)
Threads[i]->maxPly = 0;
Threads.timer->run = false; // Stop the timer
- if (Options["Write Search Log"])
- {
- Time::point elapsed = Time::now() - SearchTime + 1;
-
- Log log(Options["Search Log Filename"]);
- log << "Nodes: " << RootPos.nodes_searched()
- << "\nNodes/second: " << RootPos.nodes_searched() * 1000 / elapsed
- << "\nBest move: " << move_to_san(RootPos, RootMoves[0].pv[0]);
-
- StateInfo st;
- RootPos.do_move(RootMoves[0].pv[0], st);
- log << "\nPonder move: " << move_to_san(RootPos, RootMoves[0].pv[1]) << std::endl;
- RootPos.undo_move(RootMoves[0].pv[0]);
- }
-
finalize:
// When search is stopped this info is not printed
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 < std::min(multiPV, RootMoves.size()) && !Signals.stop; ++PVIdx)
{
// Reset aspiration window starting size
if (depth >= 5)
else
break;
- delta += delta / 2;
+ delta += 3 * delta / 8;
assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
}
// 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 == std::min(multiPV, RootMoves.size()) || 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"])
- {
- RootMove& rm = RootMoves[0];
- if (skill.best != MOVE_NONE)
- rm = *std::find(RootMoves.begin(), RootMoves.end(), skill.best);
-
- Log log(Options["Search Log Filename"]);
- log << pretty_pv(pos, depth, rm.score, Time::now() - SearchTime, &rm.pv[0])
- << std::endl;
- }
-
// Have we found a "mate in x"?
if ( Limits.mate
&& bestValue >= VALUE_MATE_IN_MAX_PLY
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
&& !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;
{
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;
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)
}
- // 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;
&& 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]);
}
assert(!this_sp || (this_sp->masterThread == this && searching));
- while (true)
+ while (!exit)
{
- // If we are not searching, wait for a condition to be signaled instead of
- // wasting CPU time polling for work.
- while (!searching || exit)
- {
- if (exit)
- {
- assert(!this_sp);
- return;
- }
-
- // Grab the lock to avoid races with Thread::notify_one()
- mutex.lock();
-
- // If we are master and all slaves have finished then exit idle_loop
- if (this_sp && this_sp->slavesMask.none())
- {
- mutex.unlock();
- break;
- }
-
- // Do sleep after retesting sleep conditions under lock protection. In
- // particular we need to avoid a deadlock in case a master thread has,
- // in the meanwhile, allocated us and sent the notify_one() call before
- // we had the chance to grab the lock.
- if (!searching && !exit)
- sleepCondition.wait(mutex);
-
- mutex.unlock();
- }
-
// If this thread has been assigned work, launch a search
if (searching)
{
- assert(!exit);
-
Threads.mutex.lock();
- assert(searching);
assert(activeSplitPoint);
SplitPoint* sp = activeSplitPoint;
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
}
}
- // If this thread is the master of a split point and all slaves have finished
- // their work at this split point, return from the idle loop.
+ // Grab the lock to avoid races with Thread::notify_one()
+ mutex.lock();
+
+ // If we are master and all slaves have finished then exit idle_loop
if (this_sp && this_sp->slavesMask.none())
{
- this_sp->mutex.lock();
- bool finished = this_sp->slavesMask.none(); // Retest under lock protection
- this_sp->mutex.unlock();
- if (finished)
- return;
+ assert(!searching);
+ mutex.unlock();
+ break;
}
+
+ // If we are not searching, wait for a condition to be signaled instead of
+ // wasting CPU time polling for work.
+ if (!searching && !exit)
+ sleepCondition.wait(mutex);
+
+ mutex.unlock();
}
}
projects / stockfish / blobdiff