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Introduce separate counter-move tables for inCheck

Enhance counter-move history table by adding a inCheck dimension. This doubles
the size of the table but provides more accurate move ordering.

STC: (yellow)
LLR: -2.94 (-2.94,2.94) [0.50,4.50]
Total: 36217 W: 7790 L: 7777 D: 20650
http://tests.stockfishchess.org/tests/view/5d9b9a290ebc5902b6d04fe0

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 36665 W: 6063 L: 5788 D: 24814
http://tests.stockfishchess.org/tests/view/5d9b9fcc0ebc5902b6d05985

Closes official-stockfish#2353

Bench: 4053577
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VoyagerOne authored and snicolet committed Oct 8, 2019
1 parent 23a0229 commit 80d59eea392fc073f6d0ba29cb9a97e3d705ee58
Showing with 15 additions and 13 deletions.
  1. +5 −5 src/search.cpp
  2. +9 −7 src/thread.cpp
  3. +1 −1 src/thread.h
@@ -334,7 +334,7 @@ void Thread::search() {

std::memset(ss-7, 0, 10 * sizeof(Stack));
for (int i = 7; i > 0; i--)
(ss-i)->continuationHistory = &this->continuationHistory[0][NO_PIECE][0]; // Use as a sentinel
(ss-i)->continuationHistory = &this->continuationHistory[0][0][NO_PIECE][0]; // Use as a sentinel

ss->pv = pv;

@@ -816,7 +816,7 @@ namespace {
Depth R = (835 + 70 * depth) / 256 + std::min(int(eval - beta) / 185, 3);

ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[0][NO_PIECE][0];
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];

pos.do_null_move(st);

@@ -867,7 +867,7 @@ namespace {
probCutCount++;

ss->currentMove = move;
ss->continuationHistory = &thisThread->continuationHistory[priorCapture][pos.moved_piece(move)][to_sq(move)];
ss->continuationHistory = &thisThread->continuationHistory[inCheck][priorCapture][pos.moved_piece(move)][to_sq(move)];

assert(depth >= 5);

@@ -1068,7 +1068,7 @@ namespace {

// Update the current move (this must be done after singular extension search)
ss->currentMove = move;
ss->continuationHistory = &thisThread->continuationHistory[priorCapture][movedPiece][to_sq(move)];
ss->continuationHistory = &thisThread->continuationHistory[inCheck][priorCapture][movedPiece][to_sq(move)];

// Step 15. Make the move
pos.do_move(move, st, givesCheck);
@@ -1475,7 +1475,7 @@ namespace {
}

ss->currentMove = move;
ss->continuationHistory = &thisThread->continuationHistory[priorCapture][pos.moved_piece(move)][to_sq(move)];
ss->continuationHistory = &thisThread->continuationHistory[inCheck][priorCapture][pos.moved_piece(move)][to_sq(move)];

// Make and search the move
pos.do_move(move, st, givesCheck);
@@ -70,13 +70,15 @@ void Thread::clear() {
mainHistory.fill(0);
captureHistory.fill(0);

for (StatsType c : { NoCaptures, Captures })
for (auto& to : continuationHistory[c])
for (auto& h : to)
h->fill(0);

for (StatsType c : { NoCaptures, Captures })
continuationHistory[c][NO_PIECE][0]->fill(Search::CounterMovePruneThreshold - 1);
for (bool inCheck : { false, true })
for (StatsType c : { NoCaptures, Captures })
for (auto& to : continuationHistory[inCheck][c])
for (auto& h : to)
h->fill(0);

for (bool inCheck : { false, true })
for (StatsType c : { NoCaptures, Captures })
continuationHistory[inCheck][c][NO_PIECE][0]->fill(Search::CounterMovePruneThreshold - 1);
}

/// Thread::start_searching() wakes up the thread that will start the search
@@ -71,7 +71,7 @@ class Thread {
CounterMoveHistory counterMoves;
ButterflyHistory mainHistory;
CapturePieceToHistory captureHistory;
ContinuationHistory continuationHistory[2];
ContinuationHistory continuationHistory[2][2];
Score contempt;
};

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