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Sync connected_threat() and yields_to_threat()

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Rename stuff so to sync as much as posisble the
two related functions.

No functional change.
This commit is contained in:
Marco Costalba 2012-11-03 15:33:46 +01:00
parent 07989712af
commit 47f988f05f
1 changed files with 29 additions and 31 deletions
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60
src/search.cpp
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@ -100,11 +100,11 @@ namespace {
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
void id_loop(Position& pos); void id_loop(Position& pos);
bool check_is_dangerous(Position& pos, Move move, Value futilityBase, Value beta);
bool yields_to_threat(const Position& pos, Move move, Move threat);
Value value_to_tt(Value v, int ply); Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply); Value value_from_tt(Value v, int ply);
bool connected_threat(const Position& pos, Move m, Move threat); bool check_is_dangerous(Position& pos, Move move, Value futilityBase, Value beta);
bool yields_to_threat(const Position& pos, Move move, Move threat);
bool prevents_threat(const Position& pos, Move move, Move threat);
string uci_pv(const Position& pos, int depth, Value alpha, Value beta); string uci_pv(const Position& pos, int depth, Value alpha, Value beta);
struct Skill { struct Skill {
@ -861,7 +861,7 @@ split_point_start: // At split points actual search starts from here
// Move count based pruning // Move count based pruning
if ( depth < 16 * ONE_PLY if ( depth < 16 * ONE_PLY
&& moveCount >= FutilityMoveCounts[depth] && moveCount >= FutilityMoveCounts[depth]
&& (!threatMove || !connected_threat(pos, move, threatMove))) && (!threatMove || !prevents_threat(pos, move, threatMove)))
{ {
if (SpNode) if (SpNode)
sp->mutex.lock(); sp->mutex.lock();
@ -1363,32 +1363,30 @@ split_point_start: // At split points actual search starts from here
assert(is_ok(move)); assert(is_ok(move));
assert(is_ok(threat)); assert(is_ok(threat));
assert(color_of(pos.piece_on(from_sq(threat))) == ~pos.side_to_move());
Square t1 = to_sq(move); Square mfrom = from_sq(move);
Square f1 = from_sq(move); Square mto = to_sq(move);
Square t2 = to_sq(threat); Square tfrom = from_sq(threat);
Square f2 = from_sq(threat); Square tto = to_sq(threat);
// We are suposed to be called upon returning from a null search
assert(color_of(pos.piece_on(f2)) == ~pos.side_to_move());
// The piece is the same or threat's destination was vacated by the move // The piece is the same or threat's destination was vacated by the move
if (t1 == f2 || t2 == f1) if (mto == tfrom || tto == mfrom)
return true; return true;
// Threat moves through the vacated square // Threat moves through the vacated square
if (between_bb(f2, t2) & f1) if (between_bb(tfrom, tto) & mfrom)
return true; return true;
// Threat's destination is defended by the move's piece // Threat's destination is defended by the move's piece
Bitboard t1_att = pos.attacks_from(pos.piece_on(t1), t1, pos.pieces() ^ f2); Bitboard matt = pos.attacks_from(pos.piece_on(mto), mto, pos.pieces() ^ tfrom);
if (t1_att & t2) if (matt & tto)
return true; return true;
// Threat gives a discovered check through the move's checking piece // Threat gives a discovered check through the move's checking piece
if (t1_att & pos.king_square(pos.side_to_move())) if (matt & pos.king_square(pos.side_to_move()))
{ {
assert(between_bb(t1, pos.king_square(pos.side_to_move())) & f2); assert(between_bb(mto, pos.king_square(pos.side_to_move())) & tfrom);
return true; return true;
} }
@ -1396,27 +1394,28 @@ split_point_start: // At split points actual search starts from here
} }
// connected_threat() tests whether it is safe to forward prune a move or if // prevents_threat() tests whether a move is able to defend against the so
// is somehow connected to the threat move returned by null search. // called threat move (the best move returned from a null search that fails
// low). In this case will not be pruned.
bool connected_threat(const Position& pos, Move m, Move threat) { bool prevents_threat(const Position& pos, Move move, Move threat) {
assert(is_ok(m)); assert(is_ok(move));
assert(is_ok(threat)); assert(is_ok(threat));
assert(!pos.is_capture_or_promotion(m)); assert(!pos.is_capture_or_promotion(move));
assert(!pos.is_passed_pawn_push(m)); assert(!pos.is_passed_pawn_push(move));
Square mfrom = from_sq(m); Square mfrom = from_sq(move);
Square mto = to_sq(m); Square mto = to_sq(move);
Square tfrom = from_sq(threat); Square tfrom = from_sq(threat);
Square tto = to_sq(threat); Square tto = to_sq(threat);
// Case 1: Don't prune moves which move the threatened piece // Don't prune moves of the threatened piece
if (mfrom == tto) if (mfrom == tto)
return true; return true;
// Case 2: If the threatened piece has value less than or equal to the // If the threatened piece has value less than or equal to the value of the
// value of the threatening piece, don't prune moves which defend it. // threat piece, don't prune moves which defend it.
if ( pos.is_capture(threat) if ( pos.is_capture(threat)
&& ( PieceValue[MG][pos.piece_on(tfrom)] >= PieceValue[MG][pos.piece_on(tto)] && ( PieceValue[MG][pos.piece_on(tfrom)] >= PieceValue[MG][pos.piece_on(tto)]
|| type_of(pos.piece_on(tfrom)) == KING)) || type_of(pos.piece_on(tfrom)) == KING))
@ -1438,11 +1437,10 @@ split_point_start: // At split points actual search starts from here
return true; return true;
} }
// Case 3: If the moving piece in the threatened move is a slider, don't // If the threat piece is a slider, don't prune safe moves which block it
// prune safe moves which block its ray.
if ( piece_is_slider(pos.piece_on(tfrom)) if ( piece_is_slider(pos.piece_on(tfrom))
&& (between_bb(tfrom, tto) & mto) && (between_bb(tfrom, tto) & mto)
&& pos.see_sign(m) >= 0) && pos.see_sign(move) >= 0)
return true; return true;
return false; return false;