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Code Issues Releases Wiki Activity

Do not extend at low depths if not in PV

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Only check extensions are allowed.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2009-11-06 16:42:02 +01:00
parent 0fdc75c0bd
commit dd884b65b7
1 changed files with 20 additions and 16 deletions
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36
src/search.cpp
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@ -284,7 +284,7 @@ namespace {
bool connected_moves(const Position& pos, Move m1, Move m2);
bool value_is_mate(Value value);
bool move_is_killer(Move m, const SearchStack& ss);
Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
Depth extension(const Position& pos, Move m, Depth depth, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
bool ok_to_do_nullmove(const Position& pos);
bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
@ -900,7 +900,7 @@ namespace {
// Decide search depth for this move
bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
bool dangerous;
ext = extension(pos, move, true, captureOrPromotion, pos.move_is_check(move), false, false, &dangerous);
ext = extension(pos, move, Depth(100), true, captureOrPromotion, pos.move_is_check(move), false, false, &dangerous);
newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
// Make the move, and search it
@ -1135,7 +1135,7 @@ namespace {
movesSearched[moveCount++] = ss[ply].currentMove = move;
// Decide the new search depth
ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
ext = extension(pos, move, depth, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
newDepth = depth - OnePly + ext;
// Make and search the move
@ -1397,7 +1397,7 @@ namespace {
movesSearched[moveCount++] = ss[ply].currentMove = move;
// Decide the new search depth
ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
ext = extension(pos, move, depth, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
newDepth = depth - OnePly + ext;
// Futility pruning
@ -1725,7 +1725,7 @@ namespace {
// Decide the new search depth.
bool dangerous;
Depth ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, false, false, &dangerous);
Depth ext = extension(pos, move, sp->depth, false, captureOrPromotion, moveIsCheck, false, false, &dangerous);
Depth newDepth = sp->depth - OnePly + ext;
// Prune?
@ -1865,7 +1865,7 @@ namespace {
// Decide the new search depth.
bool dangerous;
Depth ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
Depth ext = extension(pos, move, sp->depth, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
Depth newDepth = sp->depth - OnePly + ext;
// Make and search the move.
@ -2301,7 +2301,7 @@ namespace {
// extended, as example because the corresponding UCI option is set to zero,
// the move is marked as 'dangerous' so, at least, we avoid to prune it.
Depth extension(const Position& pos, Move m, bool pvNode, bool captureOrPromotion,
Depth extension(const Position& pos, Move m, Depth depth, bool pvNode, bool captureOrPromotion,
bool check, bool singleReply, bool mateThreat, bool* dangerous) {
assert(m != MOVE_NONE);
@ -2321,6 +2321,19 @@ namespace {
result += MateThreatExtension[pvNode];
}
if ( pvNode
&& captureOrPromotion
&& pos.type_of_piece_on(move_to(m)) != PAWN
&& pos.see_sign(m) >= 0)
{
result += OnePly/2;
*dangerous = true;
}
// Do not extend at low depths
if (!pvNode && depth < 4*OnePly)
return Min(result, OnePly); // Further test with Min(result, OnePly / 2)
if (pos.type_of_piece_on(move_from(m)) == PAWN)
{
Color c = pos.side_to_move();
@ -2347,15 +2360,6 @@ namespace {
*dangerous = true;
}
if ( pvNode
&& captureOrPromotion
&& pos.type_of_piece_on(move_to(m)) != PAWN
&& pos.see_sign(m) >= 0)
{
result += OnePly/2;
*dangerous = true;
}
return Min(result, OnePly);
}