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Code Issues Releases Wiki Activity

Clean-up skipEarlyPruning (#921)

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make skipEarlyPruning a search argument instead of managing this by hand.

Verified for no regression at STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 96754 W: 17089 L: 17095 D: 62570

No functional change.
This commit is contained in:
Joost VandeVondele 2016-12-11 20:05:25 +01:00 • committed by Marco Costalba
parent 589049a0e5
commit 1b62d413c1
2 changed files with 13 additions and 23 deletions
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33
src/search.cpp
View file

@ -162,7 +162,7 @@ namespace {
Value DrawValue[COLOR_NB];
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning);
template <NodeType NT, bool InCheck>
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
@ -407,7 +407,7 @@ void Thread::search() {
// high/low anymore.
while (true)
{
bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false);
bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false, false);
// Bring the best move to the front. It is critical that sorting
// is done with a stable algorithm because all the values but the
@ -541,7 +541,7 @@ namespace {
// search<>() is the main search function for both PV and non-PV nodes
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) {
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning) {
const bool PvNode = NT == PV;
const bool rootNode = PvNode && (ss-1)->ply == 0;
@ -617,7 +617,6 @@ namespace {
ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
ss->counterMoves = nullptr;
(ss+1)->skipEarlyPruning = false;
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
Square prevSq = to_sq((ss-1)->currentMove);
@ -712,7 +711,7 @@ namespace {
ss->staticEval, TT.generation());
}
if (ss->skipEarlyPruning)
if (skipEarlyPruning)
goto moves_loop;
// Step 6. Razoring (skipped when in check)
@ -753,10 +752,8 @@ namespace {
Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY;
pos.do_null_move(st);
(ss+1)->skipEarlyPruning = true;
nullValue = depth-R < ONE_PLY ? -qsearch<NonPV, false>(pos, ss+1, -beta, -beta+1, DEPTH_ZERO)
: - search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode);
(ss+1)->skipEarlyPruning = false;
: - search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode, true);
pos.undo_null_move();
if (nullValue >= beta)
@ -769,10 +766,8 @@ namespace {
return nullValue;
// Do verification search at high depths
ss->skipEarlyPruning = true;
Value v = depth-R < ONE_PLY ? qsearch<NonPV, false>(pos, ss, beta-1, beta, DEPTH_ZERO)
: search<NonPV>(pos, ss, beta-1, beta, depth-R, false);
ss->skipEarlyPruning = false;
: search<NonPV>(pos, ss, beta-1, beta, depth-R, false, true);
if (v >= beta)
return nullValue;
@ -801,7 +796,7 @@ namespace {
ss->currentMove = move;
ss->counterMoves = &thisThread->counterMoveHistory[pos.moved_piece(move)][to_sq(move)];
pos.do_move(move, st);
value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode, false);
pos.undo_move(move);
if (value >= rbeta)
return value;
@ -814,9 +809,7 @@ namespace {
&& (PvNode || ss->staticEval + 256 >= beta))
{
Depth d = (3 * depth / (4 * ONE_PLY) - 2) * ONE_PLY;
ss->skipEarlyPruning = true;
search<NT>(pos, ss, alpha, beta, d, cutNode);
ss->skipEarlyPruning = false;
search<NT>(pos, ss, alpha, beta, d, cutNode, true);
tte = TT.probe(posKey, ttHit);
ttMove = ttHit ? tte->move() : MOVE_NONE;
@ -898,9 +891,7 @@ moves_loop: // When in check search starts from here
Value rBeta = std::max(ttValue - 2 * depth / ONE_PLY, -VALUE_MATE);
Depth d = (depth / (2 * ONE_PLY)) * ONE_PLY;
ss->excludedMove = move;
ss->skipEarlyPruning = true;
value = search<NonPV>(pos, ss, rBeta - 1, rBeta, d, cutNode);
ss->skipEarlyPruning = false;
value = search<NonPV>(pos, ss, rBeta - 1, rBeta, d, cutNode, true);
ss->excludedMove = MOVE_NONE;
if (value < rBeta)
@ -1014,7 +1005,7 @@ moves_loop: // When in check search starts from here
Depth d = std::max(newDepth - r, ONE_PLY);
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true, false);
doFullDepthSearch = (value > alpha && d != newDepth);
}
@ -1026,7 +1017,7 @@ moves_loop: // When in check search starts from here
value = newDepth < ONE_PLY ?
givesCheck ? -qsearch<NonPV, true>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
: -qsearch<NonPV, false>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
: - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
: - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode, false);
// For PV nodes only, do a full PV search on the first move or after a fail
// high (in the latter case search only if value < beta), otherwise let the
@ -1039,7 +1030,7 @@ moves_loop: // When in check search starts from here
value = newDepth < ONE_PLY ?
givesCheck ? -qsearch<PV, true>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
: -qsearch<PV, false>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
: - search<PV>(pos, ss+1, -beta, -alpha, newDepth, false);
: - search<PV>(pos, ss+1, -beta, -alpha, newDepth, false, false);
}
// Step 17. Undo move

3
src/search.h
View file

@ -38,15 +38,14 @@ namespace Search {
struct Stack {
Move* pv;
CounterMoveStats* counterMoves;
int ply;
Move currentMove;
Move excludedMove;
Move killers[2];
Value staticEval;
Value history;
bool skipEarlyPruning;
int moveCount;
CounterMoveStats* counterMoves;
};