void idle_loop(int threadID, SplitPoint* sp);
template <bool Fake>
- void split(Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
- Depth depth, Move threatMove, bool mateThreat, int moveCount, MovePicker* mp, bool pvNode);
+ void split(Position& pos, SearchStack* ss, Value* alpha, const Value beta, Value* bestValue,
+ Depth depth, Move threatMove, int moveCount, MovePicker* mp, bool pvNode);
private:
Depth minimumSplitDepth;
// Extensions. Configurable UCI options
// Array index 0 is used at non-PV nodes, index 1 at PV nodes.
- Depth CheckExtension[2], PawnPushTo7thExtension[2], PassedPawnExtension[2];
- Depth PawnEndgameExtension[2], MateThreatExtension[2];
+ Depth CheckExtension[2], PawnPushTo7thExtension[2];
+ Depth PassedPawnExtension[2], PawnEndgameExtension[2];
// Minimum depth for use of singular extension
const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */};
int8_t ReductionMatrix[2][64][64]; // [pv][depth][moveNumber]
template <NodeType PV>
- inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / 2, 63)][Min(mn, 63)]; }
+ inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / ONE_PLY, 63)][Min(mn, 63)]; }
// Easy move margin. An easy move candidate must be at least this much
// better than the second best move.
Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove);
template <NodeType PvNode, bool SpNode, bool Root>
- Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
+ Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth);
template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth);
template <NodeType PvNode>
- inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+ inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
- return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO, ply)
- : search<PvNode, false, false>(pos, ss, alpha, beta, depth, ply);
+ return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO)
+ : search<PvNode, false, false>(pos, ss, alpha, beta, depth);
}
template <NodeType PvNode>
- Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool mateThreat, bool* dangerous);
+ Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool* dangerous);
bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue);
bool connected_moves(const Position& pos, Move m1, Move m2);
PassedPawnExtension[0] = Options["Passed Pawn Extension (non-PV nodes)"].value<Depth>();
PawnEndgameExtension[1] = Options["Pawn Endgame Extension (PV nodes)"].value<Depth>();
PawnEndgameExtension[0] = Options["Pawn Endgame Extension (non-PV nodes)"].value<Depth>();
- MateThreatExtension[1] = Options["Mate Threat Extension (PV nodes)"].value<Depth>();
- MateThreatExtension[0] = Options["Mate Threat Extension (non-PV nodes)"].value<Depth>();
UCIMultiPV = Options["MultiPV"].value<int>();
SkillLevel = Options["Skill level"].value<int>();
UseLogFile = Options["Use Search Log"].value<bool>();
SearchStack ss[PLY_MAX_PLUS_2];
Value bestValues[PLY_MAX_PLUS_2];
int bestMoveChanges[PLY_MAX_PLUS_2];
- int depth, aspirationDelta, skillSamplingDepth;
+ int depth, aspirationDelta;
Value value, alpha, beta;
Move bestMove, easyMove, skillBest, skillPonder;
TT.new_search();
H.clear();
*ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE;
- depth = aspirationDelta = skillSamplingDepth = 0;
+ depth = aspirationDelta = 0;
alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
return MOVE_NONE;
}
- // Choose a random sampling depth according to SkillLevel so that at low
- // skills there is an higher risk to pick up a blunder.
- if (SkillLevelEnabled)
- skillSamplingDepth = 4 + SkillLevel + (RK.rand<unsigned>() % 4);
-
// Iterative deepening loop
while (++depth <= PLY_MAX && (!MaxDepth || depth <= MaxDepth) && !StopRequest)
{
// research with bigger window until not failing high/low anymore.
do {
// Search starting from ss+1 to allow calling update_gains()
- value = search<PV, false, true>(pos, ss+1, alpha, beta, depth * ONE_PLY, 0);
+ value = search<PV, false, true>(pos, ss+1, alpha, beta, depth * ONE_PLY);
// Write PV back to transposition table in case the relevant entries
// have been overwritten during the search.
bestMoveChanges[depth] = Rml.bestMoveChanges;
// Do we need to pick now the best and the ponder moves ?
- if (SkillLevelEnabled && depth == skillSamplingDepth)
+ if (SkillLevelEnabled && depth == 1 + SkillLevel)
do_skill_level(&skillBest, &skillPonder);
// Send PV line to GUI and to log file
// here: This is taken care of after we return from the split point.
template <NodeType PvNode, bool SpNode, bool Root>
- Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+ Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta > alpha && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
- assert((Root || ply > 0) && ply < PLY_MAX);
assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
Move movesSearched[MOVES_MAX];
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous, isBadCap;
- bool mateThreat = false;
int moveCount = 0, playedMoveCount = 0;
int threadID = pos.thread();
SplitPoint* sp = NULL;
refinedValue = bestValue = value = -VALUE_INFINITE;
oldAlpha = alpha;
isCheck = pos.is_check();
+ ss->ply = (ss-1)->ply + 1;
if (SpNode)
{
tte = NULL;
ttMove = excludedMove = MOVE_NONE;
threatMove = sp->threatMove;
- mateThreat = sp->mateThreat;
goto split_point_start;
}
else if (Root)
if (( StopRequest
|| ThreadsMgr.cutoff_at_splitpoint(threadID)
|| pos.is_draw()
- || ply >= PLY_MAX - 1) && !Root)
+ || ss->ply > PLY_MAX) && !Root)
return VALUE_DRAW;
// Step 3. Mate distance pruning
- alpha = Max(value_mated_in(ply), alpha);
- beta = Min(value_mate_in(ply+1), beta);
+ alpha = Max(value_mated_in(ss->ply), alpha);
+ beta = Min(value_mate_in(ss->ply+1), beta);
if (alpha >= beta)
return alpha;
if ( !Root
&& tte
&& (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT
- : ok_to_use_TT(tte, depth, beta, ply)))
+ : ok_to_use_TT(tte, depth, beta, ss->ply)))
{
TT.refresh(tte);
ss->bestMove = ttMove; // Can be MOVE_NONE
- return value_from_tt(tte->value(), ply);
+ return value_from_tt(tte->value(), ss->ply);
}
// Step 5. Evaluate the position statically and update parent's gain statistics
ss->eval = tte->static_value();
ss->evalMargin = tte->static_value_margin();
- refinedValue = refine_eval(tte, ss->eval, ply);
+ refinedValue = refine_eval(tte, ss->eval, ss->ply);
}
else
{
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
Value rbeta = beta - razor_margin(depth);
- Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, DEPTH_ZERO, ply);
+ Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, DEPTH_ZERO);
if (v < rbeta)
// Logically we should return (v + razor_margin(depth)), but
// surprisingly this did slightly weaker in tests.
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
- nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
+ nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY);
(ss+1)->skipNullMove = false;
pos.undo_null_move();
// Do verification search at high depths
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, alpha, beta, depth-R*ONE_PLY, ply);
+ Value v = search<NonPV>(pos, ss, alpha, beta, depth-R*ONE_PLY);
ss->skipNullMove = false;
if (v >= beta)
// move which was reduced. If a connection is found, return a fail
// 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;
-
threatMove = (ss+1)->bestMove;
if ( depth < ThreatDepth
Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
ss->skipNullMove = true;
- search<PvNode>(pos, ss, alpha, beta, d, ply);
+ search<PvNode>(pos, ss, alpha, beta, d);
ss->skipNullMove = false;
ttMove = ss->bestMove;
tte = TT.retrieve(posKey);
}
- // Mate threat detection for PV nodes, otherwise we use null move search
- if (PvNode)
- mateThreat = pos.has_mate_threat();
-
split_point_start: // At split points actual search starts from here
// Initialize a MovePicker object for the current position
captureOrPromotion = pos.move_is_capture_or_promotion(move);
// Step 11. Decide the new search depth
- ext = extension<PvNode>(pos, move, captureOrPromotion, moveIsCheck, mateThreat, &dangerous);
+ ext = extension<PvNode>(pos, move, captureOrPromotion, moveIsCheck, &dangerous);
// Singular extension search. If all moves but one fail low on a search of
// (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move
&& move == tte->move()
&& ext < ONE_PLY)
{
- Value ttValue = value_from_tt(tte->value(), ply);
+ Value ttValue = value_from_tt(tte->value(), ss->ply);
if (abs(ttValue) < VALUE_KNOWN_WIN)
{
Value rBeta = ttValue - int(depth);
ss->excludedMove = move;
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2, ply);
+ Value v = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2);
ss->skipNullMove = false;
ss->excludedMove = MOVE_NONE;
ss->bestMove = MOVE_NONE;
if (Root && MultiPV > 1)
alpha = -VALUE_INFINITE;
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth);
}
else
{
{
alpha = SpNode ? sp->alpha : alpha;
Depth d = newDepth - ss->reduction;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
doFullDepthSearch = (value > alpha);
}
ss->reduction = 3 * ONE_PLY;
Value rAlpha = alpha - 300;
Depth d = newDepth - ss->reduction;
- value = -search<NonPV>(pos, ss+1, -(rAlpha+1), -rAlpha, d, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(rAlpha+1), -rAlpha, d);
doFullDepthSearch = (value > rAlpha);
ss->reduction = DEPTH_ZERO; // Restore original reduction
}
if (doFullDepthSearch)
{
alpha = SpNode ? sp->alpha : alpha;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth);
// Step extra. pv search (only in PV nodes)
// Search only for possible new PV nodes, if instead value >= beta then
// parent node fails low with value <= alpha and tries another move.
if (PvNode && value > alpha && (Root || value < beta))
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth);
}
}
else if (SpNode)
sp->betaCutoff = true;
- if (value == value_mate_in(ply + 1))
+ if (value == value_mate_in(ss->ply + 1))
ss->mateKiller = move;
ss->bestMove = move;
&& ThreadsMgr.available_thread_exists(threadID)
&& !StopRequest
&& !ThreadsMgr.cutoff_at_splitpoint(threadID))
- ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
- threatMove, mateThreat, moveCount, &mp, PvNode);
+ ThreadsMgr.split<FakeSplit>(pos, ss, &alpha, beta, &bestValue, depth,
+ threatMove, moveCount, &mp, PvNode);
}
// Step 19. Check for mate and stalemate
// no legal moves, it must be mate or stalemate.
// If one move was excluded return fail low score.
if (!SpNode && !moveCount)
- return excludedMove ? oldAlpha : isCheck ? value_mated_in(ply) : VALUE_DRAW;
+ return excludedMove ? oldAlpha : isCheck ? value_mated_in(ss->ply) : VALUE_DRAW;
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
: bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
- TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ss->evalMargin);
+ TT.store(posKey, value_to_tt(bestValue, ss->ply), vt, depth, move, ss->eval, ss->evalMargin);
// Update killers and history only for non capture moves that fails high
if ( bestValue >= beta
// less than ONE_PLY).
template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
assert(depth <= 0);
- assert(ply > 0 && ply < PLY_MAX);
assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
StateInfo st;
Value oldAlpha = alpha;
ss->bestMove = ss->currentMove = MOVE_NONE;
+ ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or maximum ply reached
- if (pos.is_draw() || ply >= PLY_MAX - 1)
+ if (ss->ply > PLY_MAX || pos.is_draw())
return VALUE_DRAW;
// Decide whether or not to include checks, this fixes also the type of
tte = TT.retrieve(pos.get_key());
ttMove = (tte ? tte->move() : MOVE_NONE);
- if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ply))
+ if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ss->ply))
{
ss->bestMove = ttMove; // Can be MOVE_NONE
- return value_from_tt(tte->value(), ply);
+ return value_from_tt(tte->value(), ss->ply);
}
// Evaluate the position statically
if (bestValue >= beta)
{
if (!tte)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin);
return bestValue;
}
// Make and search the move
pos.do_move(move, st, ci, moveIsCheck);
- value = -qsearch<PvNode>(pos, ss+1, -beta, -alpha, depth-ONE_PLY, ply+1);
+ value = -qsearch<PvNode>(pos, ss+1, -beta, -alpha, depth-ONE_PLY);
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.
if (isCheck && bestValue == -VALUE_INFINITE)
- return value_mated_in(ply);
+ return value_mated_in(ss->ply);
// Update transposition table
ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
// the move is marked as 'dangerous' so, at least, we avoid to prune it.
template <NodeType PvNode>
Depth extension(const Position& pos, Move m, bool captureOrPromotion,
- bool moveIsCheck, bool mateThreat, bool* dangerous) {
+ bool moveIsCheck, bool* dangerous) {
assert(m != MOVE_NONE);
Depth result = DEPTH_ZERO;
- *dangerous = moveIsCheck | mateThreat;
+ *dangerous = moveIsCheck;
- if (*dangerous)
- {
- if (moveIsCheck && pos.see_sign(m) >= 0)
- result += CheckExtension[PvNode];
-
- if (mateThreat)
- result += MateThreatExtension[PvNode];
- }
+ if (moveIsCheck && pos.see_sign(m) >= 0)
+ result += CheckExtension[PvNode];
if (pos.type_of_piece_on(move_from(m)) == PAWN)
{
{
lastInfoTime = t;
- if (dbg_show_mean)
- dbg_print_mean();
-
- if (dbg_show_hit_rate)
- dbg_print_hit_rate();
+ dbg_print_mean();
+ dbg_print_hit_rate();
// Send info on searched nodes as soon as we return to root
SendSearchedNodes = true;
(ss+1)->sp = tsp;
if (tsp->pvNode)
- search<PV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
+ search<PV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
else
- search<NonPV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
+ search<NonPV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
assert(threads[threadID].state == THREAD_SEARCHING);
// call search().When all threads have returned from search() then split() returns.
template <bool Fake>
- void ThreadsManager::split(Position& pos, SearchStack* ss, int ply, Value* alpha,
- const Value beta, Value* bestValue, Depth depth, Move threatMove,
- bool mateThreat, int moveCount, MovePicker* mp, bool pvNode) {
+ void ThreadsManager::split(Position& pos, SearchStack* ss, Value* alpha, const Value beta,
+ Value* bestValue, Depth depth, Move threatMove,
+ int moveCount, MovePicker* mp, bool pvNode) {
assert(pos.is_ok());
- assert(ply > 0 && ply < PLY_MAX);
assert(*bestValue >= -VALUE_INFINITE);
assert(*bestValue <= *alpha);
assert(*alpha < beta);
splitPoint.parent = masterThread.splitPoint;
splitPoint.master = master;
splitPoint.betaCutoff = false;
- splitPoint.ply = ply;
splitPoint.depth = depth;
splitPoint.threatMove = threatMove;
- splitPoint.mateThreat = mateThreat;
splitPoint.alpha = *alpha;
splitPoint.beta = beta;
splitPoint.pvNode = pvNode;
TTEntry* tte;
int ply = 1;
- assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+ assert(pv[0] != MOVE_NONE && pos.move_is_legal(pv[0]));
pos.do_move(pv[0], *st++);
while ( (tte = TT.retrieve(pos.get_key())) != NULL
&& tte->move() != MOVE_NONE
- && move_is_legal(pos, tte->move())
+ && pos.move_is_legal(tte->move())
&& ply < PLY_MAX
&& (!pos.is_draw() || ply < 2))
{
Value v, m = VALUE_NONE;
int ply = 0;
- assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+ assert(pv[0] != MOVE_NONE && pos.move_is_legal(pv[0]));
do {
k = pos.get_key();
projects / stockfish / blobdiff