// If this is the master thread and we have been asked to stop because of
// a beta cutoff higher up in the tree, stop all slave threads:
if (sp->master == threadID && thread_should_stop(threadID))
- for(int i = 0; i < ActiveThreads; i++)
- if(sp->slaves[i])
+ for (int i = 0; i < ActiveThreads; i++)
+ if (sp->slaves[i])
Threads[i].stop = true;
sp->cpus--;
// after we return from the split point.
void sp_search_pv(SplitPoint *sp, int threadID) {
+
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
SearchStack *ss = sp->sstack[threadID];
Value value;
Move move;
- int moveCount = sp->moves;
- while(sp->alpha < sp->beta && !thread_should_stop(threadID)
- && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE) {
- UndoInfo u;
- Depth ext, newDepth;
+ while ( sp->alpha < sp->beta
+ && !thread_should_stop(threadID)
+ && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
+ {
bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move);
PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move));
lock_grab(&(sp->lock));
- sp->moves++;
- moveCount = sp->moves;
+ int moveCount = ++sp->moves;
lock_release(&(sp->lock));
ss[sp->ply].currentMove = move;
// Decide the new search depth.
- ext = extension(pos, move, true, moveIsCheck, false, false);
- newDepth = sp->depth - OnePly + ext;
+ Depth ext = extension(pos, move, true, moveIsCheck, false, false);
+ Depth newDepth = sp->depth - OnePly + ext;
// Make and search the move.
+ UndoInfo u;
pos.do_move(move, u, sp->dcCandidates);
- if(ext == Depth(0) && moveCount >= LMRPVMoves && !moveIsCapture
- && !move_promotion(move) && !moveIsPassedPawnPush
- && !move_is_castle(move)
- && move != ss[sp->ply].killer1 && move != ss[sp->ply].killer2) {
- ss[sp->ply].reduction = OnePly;
- value = -search(pos, ss, -sp->alpha, newDepth - OnePly, sp->ply+1,
- true, threadID);
+
+ // Try to reduce non-pv search depth by one ply if move seems not problematic,
+ // if the move fails high will be re-searched at full depth.
+ if ( ext == Depth(0)
+ && moveCount >= LMRPVMoves
+ && !moveIsCapture
+ && !moveIsPassedPawnPush
+ && !move_promotion(move)
+ && !move_is_castle(move)
+ && move != ss[sp->ply].killer1
+ && move != ss[sp->ply].killer2)
+ {
+ ss[sp->ply].reduction = OnePly;
+ value = -search(pos, ss, -sp->alpha, newDepth - OnePly, sp->ply+1, true, threadID);
}
else
- value = sp->alpha + 1;
- if(value > sp->alpha) {
- ss[sp->ply].reduction = Depth(0);
- value = -search(pos, ss, -sp->alpha, newDepth, sp->ply+1, true,
- threadID);
- if(value > sp->alpha && value < sp->beta) {
- if(sp->ply == 1 && RootMoveNumber == 1)
- // When the search fails high at ply 1 while searching the first
- // move at the root, set the flag failHighPly1. This is used for
- // time managment: We don't want to stop the search early in
- // such cases, because resolving the fail high at ply 1 could
- // result in a big drop in score at the root.
- Threads[threadID].failHighPly1 = true;
- value = -search_pv(pos, ss, -sp->beta, -sp->alpha, newDepth,
- sp->ply+1, threadID);
- Threads[threadID].failHighPly1 = false;
+ value = sp->alpha + 1; // Just to trigger next condition
+
+ if (value > sp->alpha) // Go with full depth non-pv search
+ {
+ ss[sp->ply].reduction = Depth(0);
+ value = -search(pos, ss, -sp->alpha, newDepth, sp->ply+1, true, threadID);
+
+ if (value > sp->alpha && value < sp->beta)
+ {
+ // When the search fails high at ply 1 while searching the first
+ // move at the root, set the flag failHighPly1. This is used for
+ // time managment: We don't want to stop the search early in
+ // such cases, because resolving the fail high at ply 1 could
+ // result in a big drop in score at the root.
+ if (sp->ply == 1 && RootMoveNumber == 1)
+ Threads[threadID].failHighPly1 = true;
+
+ value = -search_pv(pos, ss, -sp->beta, -sp->alpha, newDepth, sp->ply+1, threadID);
+ Threads[threadID].failHighPly1 = false;
}
}
pos.undo_move(move, u);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
- if(thread_should_stop(threadID))
- break;
+ if (thread_should_stop(threadID))
+ break;
// New best move?
lock_grab(&(sp->lock));
- if(value > sp->bestValue && !thread_should_stop(threadID)) {
- sp->bestValue = value;
- if(value > sp->alpha) {
- sp->alpha = value;
- sp_update_pv(sp->parentSstack, ss, sp->ply);
- if(value == value_mate_in(sp->ply + 1))
- ss[sp->ply].mateKiller = move;
- if(value >= sp->beta) {
- for(int i = 0; i < ActiveThreads; i++)
- if(i != threadID && (i == sp->master || sp->slaves[i]))
- Threads[i].stop = true;
- sp->finished = true;
- }
+ if (value > sp->bestValue && !thread_should_stop(threadID))
+ {
+ sp->bestValue = value;
+ if (value > sp->alpha)
+ {
+ sp->alpha = value;
+ sp_update_pv(sp->parentSstack, ss, sp->ply);
+ if (value == value_mate_in(sp->ply + 1))
+ ss[sp->ply].mateKiller = move;
+
+ if(value >= sp->beta)
+ {
+ for(int i = 0; i < ActiveThreads; i++)
+ if(i != threadID && (i == sp->master || sp->slaves[i]))
+ Threads[i].stop = true;
+
+ sp->finished = true;
+ }
}
// If we are at ply 1, and we are searching the first root move at
// ply 0, set the 'Problem' variable if the score has dropped a lot
// (from the computer's point of view) since the previous iteration:
- if(Iteration >= 2 &&
- -value <= ValueByIteration[Iteration-1] - ProblemMargin)
- Problem = true;
+ if (Iteration >= 2 && -value <= ValueByIteration[Iteration-1] - ProblemMargin)
+ Problem = true;
}
lock_release(&(sp->lock));
}
// If this is the master thread and we have been asked to stop because of
// a beta cutoff higher up in the tree, stop all slave threads:
- if(sp->master == threadID && thread_should_stop(threadID))
- for(int i = 0; i < ActiveThreads; i++)
- if(sp->slaves[i])
- Threads[i].stop = true;
+ if (sp->master == threadID && thread_should_stop(threadID))
+ for (int i = 0; i < ActiveThreads; i++)
+ if (sp->slaves[i])
+ Threads[i].stop = true;
sp->cpus--;
sp->slaves[threadID] = 0;
projects / stockfish / blobdiff