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Merge remote-tracking branch 'upstream/master' into tools_merge_20210513

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This commit is contained in:
Tomasz Sobczyk
2021-05-13 10:53:57 +02:00
parent 6b24954738 594e2ac999
commit 8f0dbc9348
30 changed files with 811 additions and 903 deletions
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108
src/search.cpp
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@@ -96,49 +96,6 @@ namespace {
Move best = MOVE_NONE;
};
// Breadcrumbs are used to mark nodes as being searched by a given thread
struct Breadcrumb {
std::atomic<Thread*> thread;
std::atomic<Key> key;
};
std::array<Breadcrumb, 1024> breadcrumbs;
// ThreadHolding structure keeps track of which thread left breadcrumbs at the given
// node for potential reductions. A free node will be marked upon entering the moves
// loop by the constructor, and unmarked upon leaving that loop by the destructor.
struct ThreadHolding {
explicit ThreadHolding(Thread* thisThread, Key posKey, int ply) {
location = ply < 8 ? &breadcrumbs[posKey & (breadcrumbs.size() - 1)] : nullptr;
otherThread = false;
owning = false;
if (location)
{
// See if another already marked this location, if not, mark it ourselves
Thread* tmp = (*location).thread.load(std::memory_order_relaxed);
if (tmp == nullptr)
{
(*location).thread.store(thisThread, std::memory_order_relaxed);
(*location).key.store(posKey, std::memory_order_relaxed);
owning = true;
}
else if ( tmp != thisThread
&& (*location).key.load(std::memory_order_relaxed) == posKey)
otherThread = true;
}
}
~ThreadHolding() {
if (owning) // Free the marked location
(*location).thread.store(nullptr, std::memory_order_relaxed);
}
bool marked() { return otherThread; }
private:
Breadcrumb* location;
bool otherThread, owning;
};
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
@@ -159,7 +116,7 @@ namespace {
uint64_t perft(Position& pos, Depth depth) {
StateInfo st;
ASSERT_ALIGNED(&st, Eval::NNUE::kCacheLineSize);
ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize);
uint64_t cnt, nodes = 0;
const bool leaf = (depth == 2);
@@ -594,7 +551,7 @@ namespace {
Move pv[MAX_PLY+1], capturesSearched[32], quietsSearched[64];
StateInfo st;
ASSERT_ALIGNED(&st, Eval::NNUE::kCacheLineSize);
ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize);
TTEntry* tte;
Key posKey;
@@ -1003,8 +960,12 @@ moves_loop: // When in check, search starts from here
value = bestValue;
singularQuietLMR = moveCountPruning = false;
// Mark this node as being searched
ThreadHolding th(thisThread, posKey, ss->ply);
// Indicate PvNodes that will probably fail low if the node was searched
// at a depth equal or greater than the current depth, and the result of this search was a fail low.
bool likelyFailLow = PvNode
&& ttMove
&& (tte->bound() & BOUND_UPPER)
&& tte->depth() >= depth;
// Step 12. Loop through all pseudo-legal moves until no moves remain
// or a beta cutoff occurs.
@@ -1043,14 +1004,6 @@ moves_loop: // When in check, search starts from here
movedPiece = pos.moved_piece(move);
givesCheck = pos.gives_check(move);
// Indicate PvNodes that will probably fail low if node was searched with non-PV search
// at depth equal or greater to current depth and result of this search was far below alpha
bool likelyFailLow = PvNode
&& ttMove
&& (tte->bound() & BOUND_UPPER)
&& ttValue < alpha + 200 + 100 * depth
&& tte->depth() >= depth;
// Calculate new depth for this move
newDepth = depth - 1;
@@ -1130,6 +1083,8 @@ moves_loop: // When in check, search starts from here
{
extension = 1;
singularQuietLMR = !ttCapture;
if (!PvNode && value < singularBeta - 140)
extension = 2;
}
// Multi-cut pruning
@@ -1153,11 +1108,6 @@ moves_loop: // When in check, search starts from here
}
}
// Check extension (~2 Elo)
else if ( givesCheck
&& (pos.is_discovered_check_on_king(~us, move) || pos.see_ge(move)))
extension = 1;
// Add extension to new depth
newDepth += extension;
@@ -1185,7 +1135,8 @@ moves_loop: // When in check, search starts from here
|| ss->staticEval + PieceValue[EG][pos.captured_piece()] <= alpha
|| cutNode
|| (!PvNode && !formerPv && captureHistory[movedPiece][to_sq(move)][type_of(pos.captured_piece())] < 3678)
|| thisThread->ttHitAverage < 432 * TtHitAverageResolution * TtHitAverageWindow / 1024))
|| thisThread->ttHitAverage < 432 * TtHitAverageResolution * TtHitAverageWindow / 1024)
&& (!PvNode || ss->ply > 1 || thisThread->id() % 4 != 3))
{
Depth r = reduction(improving, depth, moveCount);
@@ -1193,10 +1144,6 @@ moves_loop: // When in check, search starts from here
if (thisThread->ttHitAverage > 537 * TtHitAverageResolution * TtHitAverageWindow / 1024)
r--;
// Increase reduction if other threads are searching this position
if (th.marked())
r++;
// Decrease reduction if position is or has been on the PV
// and node is not likely to fail low. (~10 Elo)
if ( ss->ttPv
@@ -1209,29 +1156,17 @@ moves_loop: // When in check, search starts from here
&& thisThread->bestMoveChanges <= 2)
r++;
// More reductions for late moves if position was not in previous PV
if ( moveCountPruning
&& !formerPv)
r++;
// Decrease reduction if opponent's move count is high (~5 Elo)
// Decrease reduction if opponent's move count is high (~1 Elo)
if ((ss-1)->moveCount > 13)
r--;
// Decrease reduction if ttMove has been singularly extended (~3 Elo)
// Decrease reduction if ttMove has been singularly extended (~1 Elo)
if (singularQuietLMR)
r--;
if (captureOrPromotion)
if (!captureOrPromotion)
{
// Increase reduction for non-checking captures likely to be bad
if ( !givesCheck
&& ss->staticEval + PieceValue[EG][pos.captured_piece()] + 210 * depth <= alpha)
r++;
}
else
{
// Increase reduction if ttMove is a capture (~5 Elo)
// Increase reduction if ttMove is a capture (~3 Elo)
if (ttCapture)
r++;
@@ -1242,13 +1177,6 @@ moves_loop: // When in check, search starts from here
if (cutNode)
r += 2;
// Decrease reduction for moves that escape a capture. Filter out
// castling moves, because they are coded as "king captures rook" and
// hence break reverse_move() (~2 Elo)
else if ( type_of(move) == NORMAL
&& !pos.see_ge(reverse_move(move)))
r -= 2 + ss->ttPv - (type_of(movedPiece) == PAWN);
ss->statScore = thisThread->mainHistory[us][from_to(move)]
+ (*contHist[0])[movedPiece][to_sq(move)]
+ (*contHist[1])[movedPiece][to_sq(move)]
@@ -1458,7 +1386,7 @@ moves_loop: // When in check, search starts from here
Move pv[MAX_PLY+1];
StateInfo st;
ASSERT_ALIGNED(&st, Eval::NNUE::kCacheLineSize);
ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize);
TTEntry* tte;
Key posKey;
@@ -1964,7 +1892,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) {
bool RootMove::extract_ponder_from_tt(Position& pos) {
StateInfo st;
ASSERT_ALIGNED(&st, Eval::NNUE::kCacheLineSize);
ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize);
bool ttHit;