// Book object
Book OpeningBook;
- // Pointer to root move list
+ // Root move list
RootMoveList Rml;
// MultiPV mode
#endif
- // A dispatcher to choose among different move sources according to the type of node
+ // MovePickerExt is an extended MovePicker used to choose at compile time
+ // the proper move source according to the type of node.
template<bool SpNode, bool Root> struct MovePickerExt;
- // In Root nodes use RootMoveList Rml as source. Score and sort the moves before to search them.
- template<> struct MovePickerExt<false, true> : private MovePicker {
-
- MovePickerExt(const Position& p, Move, Depth, const History& h, SearchStack* ss, Value beta)
- : MovePicker(p, Rml[0].pv[0], ONE_PLY, h, ss, beta), firstCall(true) { // FIXME use depth
-
- Move move;
- Value score = VALUE_ZERO;
-
- // Score root moves using the standard way used in main search, the moves
- // are scored according to the order in which are returned by MovePicker.
- // This is the second order score that is used to compare the moves when
- // the first order pv scores of both moves are equal.
- while ((move = MovePicker::get_next_move()) != MOVE_NONE)
- for (rm = Rml.begin(); rm != Rml.end(); ++rm)
- if (rm->pv[0] == move)
- {
- rm->non_pv_score = score--;
- break;
- }
+ // In Root nodes use RootMoveList Rml as source. Score and sort the root moves
+ // before to search them.
+ template<> struct MovePickerExt<false, true> : public MovePicker {
+
+ MovePickerExt(const Position& p, Move, Depth d, const History& h, SearchStack* ss, Value b)
+ : MovePicker(p, Rml[0].pv[0], d, h, ss, b), firstCall(true) {
+ Move move;
+ Value score = VALUE_ZERO;
+
+ // Score root moves using the standard way used in main search, the moves
+ // are scored according to the order in which are returned by MovePicker.
+ // This is the second order score that is used to compare the moves when
+ // the first order pv scores of both moves are equal.
+ while ((move = MovePicker::get_next_move()) != MOVE_NONE)
+ for (rm = Rml.begin(); rm != Rml.end(); ++rm)
+ if (rm->pv[0] == move)
+ {
+ rm->non_pv_score = score--;
+ break;
+ }
- Rml.sort();
- rm = Rml.begin();
- }
+ Rml.sort();
+ rm = Rml.begin();
+ }
- Move get_next_move() {
+ Move get_next_move() {
- if (!firstCall)
- ++rm;
- else
- firstCall = false;
+ if (!firstCall)
+ ++rm;
+ else
+ firstCall = false;
- return rm != Rml.end() ? rm->pv[0] : MOVE_NONE;
- }
- int number_of_evasions() const { return (int)Rml.size(); }
+ return rm != Rml.end() ? rm->pv[0] : MOVE_NONE;
+ }
+ int number_of_evasions() const { return (int)Rml.size(); }
- RootMoveList::iterator rm;
- bool firstCall;
+ RootMoveList::iterator rm;
+ bool firstCall;
};
- // In SpNodes use split point's shared MovePicker as move source
- template<> struct MovePickerExt<true, false> {
+ // In SpNodes use split point's shared MovePicker object as move source
+ template<> struct MovePickerExt<true, false> : public MovePicker {
- MovePickerExt(const Position&, Move, Depth, const History&, SearchStack* ss, Value)
- : mp(ss->sp->mp) {}
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h,
+ SearchStack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b),
+ mp(ss->sp->mp) {}
- Move get_next_move() { return mp->get_next_move(); }
- int number_of_evasions() const { return mp->number_of_evasions(); }
+ Move get_next_move() { return mp->get_next_move(); }
- RootMoveList::iterator rm; // Dummy, never used
- MovePicker* mp;
+ RootMoveList::iterator rm; // Dummy, needed to compile
+ MovePicker* mp;
};
- // Normal case, create and use a MovePicker object as source
+ // Default case, create and use a MovePicker object as source
template<> struct MovePickerExt<false, false> : public MovePicker {
- MovePickerExt(const Position& p, Move ttm, Depth d, const History& h,
- SearchStack* ss, Value beta) : MovePicker(p, ttm, d, h, ss, beta) {}
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h,
+ SearchStack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b) {}
- RootMoveList::iterator rm; // Dummy, never used
+ RootMoveList::iterator rm; // Dummy, needed to compile
};
} // namespace
namespace {
- // id_loop() is the main iterative deepening loop. It calls search()
- // repeatedly with increasing depth until the allocated thinking time has
- // been consumed, the user stops the search, or the maximum search depth is
- // reached.
+ // id_loop() is the main iterative deepening loop. It calls search() repeatedly
+ // with increasing depth until the allocated thinking time has been consumed,
+ // user stops the search, or the maximum search depth is reached.
Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove) {
int iteration, researchCountFL, researchCountFH, aspirationDelta;
Value value, alpha, beta;
Depth depth;
- Move EasyMove;
+ Move bestMove, easyMove;
// Moves to search are verified, scored and sorted
Rml.init(pos, searchMoves);
H.clear();
memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack));
alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
- EasyMove = MOVE_NONE;
+ *ponderMove = bestMove = easyMove = MOVE_NONE;
aspirationDelta = 0;
iteration = 1;
+ ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
// Handle special case of searching on a mate/stale position
if (Rml.size() == 0)
// Is one move significantly better than others after initial scoring ?
if ( Rml.size() == 1
|| Rml[0].pv_score > Rml[1].pv_score + EasyMoveMargin)
- EasyMove = Rml[0].pv[0];
+ easyMove = Rml[0].pv[0];
// Iterative deepening loop
while (++iteration <= PLY_MAX && (!MaxDepth || iteration <= MaxDepth) && !StopRequest)
beta = Min(bestValues[iteration - 1] + aspirationDelta, VALUE_INFINITE);
}
- // We start with small aspiration window and in case of fail high/low, we
- // research with bigger window until we are not failing high/low anymore.
+ // Start with a small aspiration window and, in case of fail high/low,
+ // research with bigger window until not failing high/low anymore.
while (true)
{
- // Search to the current depth
- value = search<PV, false, true>(pos, ss, alpha, beta, depth, 0);
+ // Search starting from ss+1 to allow calling update_gains()
+ value = search<PV, false, true>(pos, ss+1, alpha, beta, depth, 0);
- // Sort root moves and write PV lines to transposition table, in case
- // the relevant entries have been overwritten during the search.
- Rml.sort();
+ // Write PV lines to transposition table, in case the relevant entries
+ // have been overwritten during the search.
for (int i = 0; i < Min(MultiPV, (int)Rml.size()); i++)
Rml[i].insert_pv_in_tt(pos);
// Value cannot be trusted. Break out immediately!
if (StopRequest)
- break; // FIXME move to 'while' condition
+ break;
assert(value >= alpha);
- bestMoveChanges[iteration] = Rml.bestMoveChanges; // FIXME move outside fail high/low loop
-
// In case of failing high/low increase aspiration window and research,
// otherwise exit the fail high/low loop.
if (value >= beta)
break;
}
- //Save info about search result
+ // Collect info about search result
+ bestMove = Rml[0].pv[0];
bestValues[iteration] = value;
+ bestMoveChanges[iteration] = Rml.bestMoveChanges;
// Drop the easy move if differs from the new best move
- if (Rml[0].pv[0] != EasyMove)
- EasyMove = MOVE_NONE;
+ if (bestMove != easyMove)
+ easyMove = MOVE_NONE;
if (UseTimeManagement && !StopRequest)
{
// Time to stop?
bool noMoreTime = false;
- // Stop search early if there is only a single legal move,
- // we search up to Iteration 6 anyway to get a proper score.
- if (iteration >= 6 && Rml.size() == 1)
- noMoreTime = true;
-
// Stop search early when the last two iterations returned a mate score
if ( iteration >= 6
&& abs(bestValues[iteration]) >= abs(VALUE_MATE) - 100
&& abs(bestValues[iteration-1]) >= abs(VALUE_MATE) - 100)
noMoreTime = true;
- // Stop search early if one move seems to be much better than the others
+ // Stop search early if one move seems to be much better than the
+ // others or if there is only a single legal move. In this latter
+ // case we search up to Iteration 8 anyway to get a proper score.
if ( iteration >= 8
- && EasyMove == Rml[0].pv[0]
- && ( ( Rml[0].nodes > (pos.nodes_searched() * 85) / 100
+ && easyMove == bestMove
+ && ( Rml.size() == 1
+ ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100
&& current_search_time() > TimeMgr.available_time() / 16)
||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100
&& current_search_time() > TimeMgr.available_time() / 32)))
}
*ponderMove = Rml[0].pv[1];
- return Rml[0].pv[0];
+ return bestMove;
}
ss->currentMove = ss->bestMove = threatMove = MOVE_NONE;
(ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE;
- if (!Root) // FIXME remove
+ if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
{
- if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
- {
- NodesSincePoll = 0;
- poll(pos);
- }
-
- // Step 2. Check for aborted search and immediate draw
- if ( StopRequest
- || ThreadsMgr.cutoff_at_splitpoint(threadID)
- || pos.is_draw()
- || ply >= PLY_MAX - 1)
- return VALUE_DRAW;
-
- // Step 3. Mate distance pruning
- alpha = Max(value_mated_in(ply), alpha);
- beta = Min(value_mate_in(ply+1), beta);
- if (alpha >= beta)
- return alpha;
+ NodesSincePoll = 0;
+ poll(pos);
}
- // Step 4. Transposition table lookup
+ // Step 2. Check for aborted search and immediate draw
+ if (( StopRequest
+ || ThreadsMgr.cutoff_at_splitpoint(threadID)
+ || pos.is_draw()
+ || ply >= PLY_MAX - 1) && !Root)
+ return VALUE_DRAW;
+
+ // Step 3. Mate distance pruning
+ alpha = Max(value_mated_in(ply), alpha);
+ beta = Min(value_mate_in(ply+1), beta);
+ if (alpha >= beta)
+ return alpha;
+ // Step 4. Transposition table lookup
// We don't want the score of a partial search to overwrite a previous full search
// TT value, so we use a different position key in case of an excluded move exists.
excludedMove = ss->excludedMove;
}
// Save gain for the parent non-capture move
- if (!Root)
- update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
+ update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
// Step 6. Razoring (is omitted in PV nodes)
if ( !PvNode
}
// Step 9. Internal iterative deepening
- if ( !Root
- && depth >= IIDDepth[PvNode]
- && ttMove == MOVE_NONE
+ if ( depth >= IIDDepth[PvNode]
+ && ttMove == MOVE_NONE
&& (PvNode || (!isCheck && ss->eval >= beta - IIDMargin)))
{
Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
}
// Expensive mate threat detection (only for PV nodes)
- if (PvNode && !Root) // FIXME
+ if (PvNode)
mateThreat = pos.has_mate_threat();
split_point_start: // At split points actual search starts from here
&& !StopRequest
&& !ThreadsMgr.cutoff_at_splitpoint(threadID))
ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
- threatMove, mateThreat, moveCount, (MovePicker*)&mp, PvNode);
+ threatMove, mateThreat, moveCount, &mp, PvNode);
}
// Step 19. Check for mate and stalemate
projects / stockfish / blobdiff