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_search_stack(SearchStack ss[]);
void init_node(const Position &pos, 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);
- Depth extension(const Position &pos, Move m, bool pvNode, bool check,
- bool singleReply, bool mateThreat);
+ bool move_is_killer(Move m, const SearchStack& ss);
+ Depth extension(const Position &pos, Move m, bool pvNode, bool check, bool singleReply, bool mateThreat);
bool ok_to_do_nullmove(const Position &pos);
bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d);
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);
+ void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount);
+ void update_killers(Move m, SearchStack& ss);
bool fail_high_ply_1();
int current_search_time();
TimeAdvantage = myTime - oppTime;
if (!movesToGo) // Sudden death time control
- {
- if (increment)
+ {
+ if (myIncrement)
{
MaxSearchTime = myTime / 30 + myIncrement;
AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
if (Problem && StopOnPonderhit)
StopOnPonderhit = false;
- }
+ }
else
{
value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
&& !move_promotion(move)
&& !moveIsPassedPawnPush
&& !move_is_castle(move)
- && move != ss[ply].killers[0]
- && move != ss[ply].killers[1])
+ && !move_is_killer(move, ss[ply]))
{
ss[ply].reduction = OnePly;
value = -search(pos, ss, -alpha, newDepth-OnePly, ply+1, true, threadID);
if (ok_to_history(pos, m)) // Only non capture moves are considered
{
update_history(pos, m, depth, movesSearched, moveCount);
- if (m != ss[ply].killers[0])
- {
- ss[ply].killers[1] = ss[ply].killers[0];
- ss[ply].killers[0] = m;
- }
+ update_killers(m, ss[ply]);
}
TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER);
}
&& !move_promotion(move)
&& !moveIsPassedPawnPush
&& !move_is_castle(move)
- && move != ss[ply].killers[0]
- && move != ss[ply].killers[1])
+ && !move_is_killer(move, ss[ply]))
{
ss[ply].reduction = OnePly;
value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID);
if (ok_to_history(pos, m)) // Only non capture moves are considered
{
update_history(pos, m, depth, movesSearched, moveCount);
- if (m != ss[ply].killers[0])
- {
- ss[ply].killers[1] = ss[ply].killers[0];
- ss[ply].killers[0] = m;
- }
+ update_killers(m, ss[ply]);
}
TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER);
}
// Don't search captures and checks with negative SEE values
if ( !isCheck
&& !move_promotion(move)
- && !pvNode
&& (pos.midgame_value_of_piece_on(move_from(move)) >
pos.midgame_value_of_piece_on(move_to(move)))
&& pos.see(move) < 0)
if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered
{
// Wrong to update history when depth is <= 0
-
- if (m != ss[ply].killers[0])
- {
- ss[ply].killers[1] = ss[ply].killers[0];
- ss[ply].killers[0] = m;
- }
+ update_killers(m, ss[ply]);
}
return bestValue;
}
&& !moveIsPassedPawnPush
&& !move_promotion(move)
&& !move_is_castle(move)
- && move != ss[sp->ply].killers[0]
- && move != ss[sp->ply].killers[1])
+ && !move_is_killer(move, ss[sp->ply]))
{
ss[sp->ply].reduction = OnePly;
value = -search(pos, ss, -(sp->beta-1), newDepth - OnePly, sp->ply+1, true, threadID);
&& !moveIsPassedPawnPush
&& !move_promotion(move)
&& !move_is_castle(move)
- && move != ss[sp->ply].killers[0]
- && move != ss[sp->ply].killers[1])
+ && !move_is_killer(move, ss[sp->ply]))
{
ss[sp->ply].reduction = OnePly;
value = -search(pos, ss, -sp->alpha, newDepth - OnePly, sp->ply+1, true, threadID);
// init_search_stack() initializes a search stack at the beginning of a
// new search from the root.
- void init_search_stack(SearchStack ss) {
+ void init_search_stack(SearchStack& ss) {
ss.pv[0] = MOVE_NONE;
ss.pv[1] = MOVE_NONE;
ss.threatMove = MOVE_NONE;
ss.reduction = Depth(0);
for (int j = 0; j < KILLER_MAX; j++)
- ss.killers[j] = MOVE_NONE;
+ ss.killers[j] = MOVE_NONE;
}
void init_search_stack(SearchStack ss[]) {
ss[ply].pv[ply] = ss[ply].pv[ply+1] = ss[ply].currentMove = MOVE_NONE;
ss[ply+2].mateKiller = MOVE_NONE;
- ss[ply+2].killers[0] = ss[ply+2].killers[1] = 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;
if(Threads[threadID].printCurrentLine)
print_current_line(ss, ply, threadID);
}
+ // move_is_killer() checks if the given move is among the
+ // killer moves of that ply.
+
+ bool move_is_killer(Move m, const SearchStack& ss) {
+
+ const Move* k = ss.killers;
+ for (int i = 0; i < KILLER_MAX; i++, k++)
+ if (*k == m)
+ return true;
+
+ return false;
+ }
+
+
// extension() decides whether a move should be searched with normal depth,
// or with extended depth. Certain classes of moves (checking moves, in
// particular) are searched with bigger depth than ordinary moves.
- pos.midgame_value_of_piece_on(move_to(m)) == Value(0))
&& !move_promotion(m))
result += PawnEndgameExtension[pvNode];
-
+
if ( pvNode
&& pos.move_is_capture(m)
&& pos.type_of_piece_on(move_to(m)) != PAWN
}
}
+
+ // update_killers() add a good move that produced a beta-cutoff
+ // among the killer moves of that ply.
+
+ void update_killers(Move m, SearchStack& ss) {
+
+ if (m == ss.killers[0])
+ return;
+
+ for (int i = KILLER_MAX - 1; i > 0; i--)
+ ss.killers[i] = ss.killers[i - 1];
+
+ ss.killers[0] = m;
+ }
+
// fail_high_ply_1() checks if some thread is currently resolving a fail
// high at ply 1 at the node below the first root node. This information
// is used for time managment.