#include <cassert>
#include "movepick.h"
-#include "thread.h"
namespace {
// partial_insertion_sort() sorts moves in descending order up to and including
// a given limit. The order of moves smaller than the limit is left unspecified.
- // To keep the implementation simple, *begin is always included in the sorted moves.
void partial_insertion_sort(ExtMove* begin, ExtMove* end, int limit) {
- for (ExtMove *sortedEnd = begin + 1, *p = begin + 1; p < end; ++p)
+ for (ExtMove *sortedEnd = begin, *p = begin + 1; p < end; ++p)
if (p->value >= limit)
{
ExtMove tmp = *p, *q;
- *p = *sortedEnd;
- for (q = sortedEnd; q != begin && *(q-1) < tmp; --q)
- *q = *(q-1);
+ *p = *++sortedEnd;
+ for (q = sortedEnd; q != begin && *(q - 1) < tmp; --q)
+ *q = *(q - 1);
*q = tmp;
- ++sortedEnd;
}
}
/// search captures, promotions, and some checks) and how important good move
/// ordering is at the current node.
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Search::Stack* s)
- : pos(p), ss(s), depth(d) {
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh,
+ const PieceToHistory** ch, Move cm, Move* killers_p)
+ : pos(p), mainHistory(mh), contHistory(ch), countermove(cm),
+ killers{killers_p[0], killers_p[1]}, depth(d){
assert(d > DEPTH_ZERO);
- Square prevSq = to_sq((ss-1)->currentMove);
- countermove = pos.this_thread()->counterMoves[pos.piece_on(prevSq)][prevSq];
- killers[0] = ss->killers[0];
- killers[1] = ss->killers[1];
-
stage = pos.checkers() ? EVASION : MAIN_SEARCH;
ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
stage += (ttMove == MOVE_NONE);
}
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Square s)
- : pos(p) {
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh,
+ const PieceToHistory** ch, Square s)
+ : pos(p), mainHistory(mh), contHistory(ch) {
assert(d <= DEPTH_ZERO);
stage += (ttMove == MOVE_NONE);
}
+/// score() assigns a numerical value to each move in a list, used for sorting.
+/// Captures are ordered by Most Valuable Victim (MVV), preferring captures
+/// near our home rank. Quiets are ordered using the histories.
+template<GenType T>
+void MovePicker::score() {
-/// score() assigns a numerical value to each move in a move list. The moves with
-/// highest values will be picked first.
-template<>
-void MovePicker::score<CAPTURES>() {
- // Winning and equal captures in the main search are ordered by MVV, preferring
- // captures near our home rank. Surprisingly, this appears to perform slightly
- // better than SEE-based move ordering: exchanging big pieces before capturing
- // a hanging piece probably helps to reduce the subtree size.
- // In the main search we want to push captures with negative SEE values to the
- // badCaptures[] array, but instead of doing it now we delay until the move
- // has been picked up, saving some SEE calls in case we get a cutoff.
for (auto& m : *this)
- m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
- - Value(200 * relative_rank(pos.side_to_move(), to_sq(m)));
+ if (T == CAPTURES || (T == EVASIONS && pos.capture(m)))
+ m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
+ - (T == EVASIONS ? Value(type_of(pos.moved_piece(m)))
+ : Value(200 * relative_rank(pos.side_to_move(), to_sq(m))));
+ else if (T == QUIETS)
+ m.value = (*mainHistory)[pos.side_to_move()][from_to(m)]
+ + (*contHistory[0])[pos.moved_piece(m)][to_sq(m)]
+ + (*contHistory[1])[pos.moved_piece(m)][to_sq(m)]
+ + (*contHistory[3])[pos.moved_piece(m)][to_sq(m)];
+
+ else // Quiet evasions
+ m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] - (1 << 28);
}
-template<>
-void MovePicker::score<QUIETS>() {
-
- const HistoryStats& history = pos.this_thread()->history;
-
- const CounterMoveStats& cmh = *(ss-1)->counterMoves;
- const CounterMoveStats& fmh = *(ss-2)->counterMoves;
- const CounterMoveStats& fm2 = *(ss-4)->counterMoves;
-
- Color c = pos.side_to_move();
-
- for (auto& m : *this)
- m.value = cmh[pos.moved_piece(m)][to_sq(m)]
- + fmh[pos.moved_piece(m)][to_sq(m)]
- + fm2[pos.moved_piece(m)][to_sq(m)]
- + history.get(c, m);
-}
-
-template<>
-void MovePicker::score<EVASIONS>() {
- // Try captures ordered by MVV/LVA, then non-captures ordered by stats heuristics
- const HistoryStats& history = pos.this_thread()->history;
- Color c = pos.side_to_move();
-
- for (auto& m : *this)
- if (pos.capture(m))
- m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
- - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max;
- else
- m.value = history.get(c, m);
-}
-
-
/// next_move() is the most important method of the MovePicker class. It returns
/// a new pseudo legal move every time it is called, until there are no more moves
/// left. It picks the move with the biggest value from a list of generated moves
endMoves = generate<CAPTURES>(pos, cur);
score<CAPTURES>();
++stage;
+ /* fallthrough */
case GOOD_CAPTURES:
while (cur < endMoves)
move = pick_best(cur++, endMoves);
if (move != ttMove)
{
- if (pos.see_ge(move, VALUE_ZERO))
+ if (pos.see_ge(move))
return move;
// Losing capture, move it to the beginning of the array
&& pos.pseudo_legal(move)
&& !pos.capture(move))
return move;
+ /* fallthrough */
case KILLERS:
++stage;
&& pos.pseudo_legal(move)
&& !pos.capture(move))
return move;
+ /* fallthrough */
case COUNTERMOVE:
++stage;
&& pos.pseudo_legal(move)
&& !pos.capture(move))
return move;
+ /* fallthrough */
case QUIET_INIT:
cur = endBadCaptures;
score<QUIETS>();
partial_insertion_sort(cur, endMoves, -4000 * depth / ONE_PLY);
++stage;
+ /* fallthrough */
case QUIET:
while ( cur < endMoves
}
++stage;
cur = moves; // Point to beginning of bad captures
+ /* fallthrough */
case BAD_CAPTURES:
if (cur < endBadCaptures)
endMoves = generate<EVASIONS>(pos, cur);
score<EVASIONS>();
++stage;
+ /* fallthrough */
case ALL_EVASIONS:
while (cur < endMoves)
endMoves = generate<CAPTURES>(pos, cur);
score<CAPTURES>();
++stage;
+ /* fallthrough */
case PROBCUT_CAPTURES:
while (cur < endMoves)
endMoves = generate<CAPTURES>(pos, cur);
score<CAPTURES>();
++stage;
+ /* fallthrough */
case QCAPTURES_1: case QCAPTURES_2:
while (cur < endMoves)
cur = moves;
endMoves = generate<QUIET_CHECKS>(pos, cur);
++stage;
+ /* fallthrough */
case QCHECKS:
while (cur < endMoves)
endMoves = generate<CAPTURES>(pos, cur);
score<CAPTURES>();
++stage;
+ /* fallthrough */
case QRECAPTURES:
while (cur < endMoves)
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