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Code Issues Releases Wiki Activity

Simplify captures ordering

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A big simplification and removing of useless code.

Finished at 50% both at short TC (with SPRT) than
at long TC at fixed number of games:
ELO: -0.14 +-3.4 (95%) LOS: 46.8%
Total: 15206 W: 2836 L: 2842 D: 9528

bench: 5059948
This commit is contained in:
Marco Costalba 2013-07-21 01:45:47 +02:00
parent b0fd2b6b98
commit 4064ee5406
3 changed files with 5 additions and 18 deletions
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19
src/movepick.cpp
View file

@ -70,12 +70,11 @@ namespace {
/// search captures, promotions and some checks) and about how important good /// search captures, promotions and some checks) and about how important good
/// move ordering is at the current node. /// move ordering is at the current node.
MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h, Move* cm, MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
Search::Stack* s, Value beta) : pos(p), history(h), depth(d) { Move* cm, Search::Stack* s) : pos(p), history(h), depth(d) {
assert(d > DEPTH_ZERO); assert(d > DEPTH_ZERO);
captureThreshold = 0;
cur = end = moves; cur = end = moves;
endBadCaptures = moves + MAX_MOVES - 1; endBadCaptures = moves + MAX_MOVES - 1;
countermoves = cm; countermoves = cm;
@ -85,18 +84,8 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats&
stage = EVASION; stage = EVASION;
else else
{
stage = MAIN_SEARCH; stage = MAIN_SEARCH;
// Consider sligtly negative captures as good if at low depth and far from beta
if (ss->staticEval < beta - PawnValueMg && d < 3 * ONE_PLY)
captureThreshold = -PawnValueMg;
// Consider negative captures as good if still enough to reach beta
else if (ss->staticEval > beta)
captureThreshold = beta - ss->staticEval;
}
ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE); ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
end += (ttMove != MOVE_NONE); end += (ttMove != MOVE_NONE);
} }
@ -317,9 +306,7 @@ Move MovePicker::next_move<false>() {
move = pick_best(cur++, end)->move; move = pick_best(cur++, end)->move;
if (move != ttMove) if (move != ttMove)
{ {
assert(captureThreshold <= 0); // Otherwise we cannot use see_sign() if (pos.see_sign(move) >= 0)
if (pos.see_sign(move) >= captureThreshold)
return move; return move;
// Losing capture, move it to the tail of the array // Losing capture, move it to the tail of the array

2
src/movepick.h
View file

@ -86,7 +86,7 @@ class MovePicker {
public: public:
MovePicker(const Position&, Move, Depth, const HistoryStats&, Square); MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
MovePicker(const Position&, Move, const HistoryStats&, PieceType); MovePicker(const Position&, Move, const HistoryStats&, PieceType);
MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Search::Stack*, Value); MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Search::Stack*);
template<bool SpNode> Move next_move(); template<bool SpNode> Move next_move();

2
src/search.cpp
View file

@ -762,7 +762,7 @@ moves_loop: // When in check and at SpNode search starts from here
Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first, Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second }; Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
MovePicker mp(pos, ttMove, depth, History, countermoves, ss, PvNode ? -VALUE_INFINITE : beta); MovePicker mp(pos, ttMove, depth, History, countermoves, ss);
CheckInfo ci(pos); CheckInfo ci(pos);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
singularExtensionNode = !RootNode singularExtensionNode = !RootNode