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Use refinedValue in ProbCut condition

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After 12613 games at 20"+0.1 on QUAD
Mod vs Orig 1870 - 1863 - 8880 ELO +0 (+- 3.3)

So no performance change but it is a code semplification
and also is more easy to understand.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2011-06-08 18:03:26 +01:00
parent 3dfff5bdae
commit e0215f3222
4 changed files with 6 additions and 12 deletions
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4
src/movepick.cpp
View file

@ -110,13 +110,13 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h)
go_next_phase();
}
MovePicker::MovePicker(const Position& p, Move ttm, const History& h, int parentCapture)
MovePicker::MovePicker(const Position& p, Move ttm, const History& h, int threshold)
: pos(p), H(h) {
assert (!pos.in_check());
// In ProbCut we consider only captures better than parent's move
captureThreshold = parentCapture;
captureThreshold = threshold;
phasePtr = ProbCutTable;
if ( ttm != MOVE_NONE

2
src/movepick.h
View file

@ -42,7 +42,7 @@ class MovePicker {
public:
MovePicker(const Position&, Move, Depth, const History&, SearchStack*, Value);
MovePicker(const Position&, Move, Depth, const History&);
MovePicker(const Position&, Move, const History&, int parentCapture);
MovePicker(const Position&, Move, const History&, int threshold);
Move get_next_move();
private:

5
src/position.h
View file

@ -213,7 +213,6 @@ public:
// Static exchange evaluation
int see(Move m) const;
int see_sign(Move m) const;
static int see_value(PieceType pt);
// Accessing hash keys
Key get_key() const;
@ -467,10 +466,6 @@ inline bool Position::square_is_weak(Square s, Color c) const {
return !(pieces(PAWN, opposite_color(c)) & attack_span_mask(c, s));
}
inline int Position::see_value(PieceType pt) {
return seeValues[pt];
}
inline Key Position::get_key() const {
return st->key;
}

7
src/search.cpp
View file

@ -903,9 +903,8 @@ namespace {
}
// Step 9. ProbCut (is omitted in PV nodes)
// If we have a very good capture (i.e. SEE > seeValues[captured_piece_type])
// and a reduced search returns a value much above beta, we can (almost) safely
// prune the previous move.
// If we have a good capture that raises the score well above beta and a reduced
// search confirms the score then we can (almost) safely prune the previous move.
if ( !PvNode
&& depth >= RazorDepth + ONE_PLY
&& !inCheck
@ -918,7 +917,7 @@ namespace {
assert(rdepth >= ONE_PLY);
MovePicker mp(pos, ttMove, H, Position::see_value(pos.captured_piece_type()));
MovePicker mp(pos, ttMove, H, Max(rbeta - refinedValue, VALUE_ZERO));
pinned = pos.pinned_pieces(pos.side_to_move());
while ((move = mp.get_next_move()) != MOVE_NONE)