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