kate/BadFish
1
0
Fork 0
mirror of https://github.com/sockspls/badfish synced 2025-04-30 00:33:09 +00:00
Code Issues Releases Wiki Activity

Simplify threats

Browse source 
Using less parameters and code to compute Threats
Includes also a few spacing edits.

Run as a simplification.

Passed STC 10+0.1
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 18879 W: 3725 L: 3600 D: 11554

Passed LTC 60+0.4
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 74116 W: 11001 L: 10958 D: 52157

bench: 8004751
This commit is contained in:
Alain SAVARD 2015-10-18 22:17:37 -04:00 • committed by Marco Costalba
parent 4eca981e55
commit 55758344d3
3 changed files with 24 additions and 37 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

57
src/evaluate.cpp
View file

@ -148,17 +148,16 @@ namespace {
{ S(18, 5), S(27, 8) } // Bishops
};
// Threat[defended/weak][minor/rook attacking][attacked PieceType] contains
// Threat[minor/rook][attacked PieceType] contains
// bonuses according to which piece type attacks which one.
const Score Threat[][2][PIECE_TYPE_NB] = {
{ { S(0, 0), S( 0, 0), S(19, 37), S(24, 37), S(44, 97), S(35,106) }, // Minor on Defended
{ S(0, 0), S( 0, 0), S( 9, 14), S( 9, 14), S( 7, 14), S(24, 48) } }, // Rook on Defended
{ { S(0, 0), S( 0,32), S(33, 41), S(31, 50), S(41,100), S(35,104) }, // Minor on Weak
{ S(0, 0), S( 0,27), S(26, 57), S(26, 57), S(0 , 43), S(23, 51) } } // Rook on Weak
// Attacks on lesser pieces which are pawn defended are not considered.
const Score Threat[2][PIECE_TYPE_NB] = {
{ S(0, 0), S(0, 32), S(25, 39), S(28, 44), S(42, 98), S(35,105) }, // Minor attacks
{ S(0, 0), S(0, 27), S(26, 57), S(26, 57), S( 0, 30), S(23, 51) } // Rook attacks
};
// ThreatenedByPawn[PieceType] contains a penalty according to which piece
// type is attacked by an enemy pawn.
// type is attacked by a pawn.
const Score ThreatenedByPawn[PIECE_TYPE_NB] = {
S(0, 0), S(0, 0), S(107, 138), S(84, 122), S(114, 203), S(121, 217)
};
@ -484,7 +483,6 @@ namespace {
const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
enum { Defended, Weak };
enum { Minor, Rook };
Bitboard b, weak, defended, safeThreats;
@ -510,33 +508,21 @@ namespace {
// Non-pawn enemies defended by a pawn
defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Them][PAWN];
// Add a bonus according to the kind of attacking pieces
if (defended)
{
b = defended & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
while (b)
score += Threat[Defended][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
b = defended & ei.attackedBy[Us][ROOK];
while (b)
score += Threat[Defended][Rook][type_of(pos.piece_on(pop_lsb(&b)))];
}
// Enemies not defended by a pawn and under our attack
weak = pos.pieces(Them)
& ~ei.attackedBy[Them][PAWN]
& ei.attackedBy[Us][ALL_PIECES];
// Add a bonus according to the kind of attacking pieces
if (weak)
if (defended | weak)
{
b = weak & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
while (b)
score += Threat[Weak][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
score += Threat[Minor][type_of(pos.piece_on(pop_lsb(&b)))];
b = weak & ei.attackedBy[Us][ROOK];
b = (pos.pieces(Them, QUEEN) | weak) & ei.attackedBy[Us][ROOK];
while (b)
score += Threat[Weak][Rook][type_of(pos.piece_on(pop_lsb(&b)))];
score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))];
b = weak & ~ei.attackedBy[Them][ALL_PIECES];
if (b)
@ -688,24 +674,25 @@ namespace {
}
// evaluate_initiative() computes the initiative correction value for the position, i.e.
// second order bonus/malus based on the known attacking/defending status of the players.
// evaluate_initiative() computes the initiative correction value for the
// position, i.e. second order bonus/malus based on the known attacking/defending
// status of the players.
Score evaluate_initiative(const Position& pos, const EvalInfo& ei, const Score positional_score) {
int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
int king_separation = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
int asymmetry = ei.pi->pawn_asymmetry();
int king_separation = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
int asymmetry = ei.pi->pawn_asymmetry();
// Compute the initiative bonus for the attacking side
int attacker_bonus = 8 * (pawns + asymmetry + king_separation) - 120;
int attacker_bonus = 8 * (pawns + asymmetry + king_separation) - 120;
// Now apply the bonus: note that we find the attacking side by extracting the sign
// Now apply the bonus: note that we find the attacking side by extracting the sign
// of the endgame value of "positional_score", and that we carefully cap the bonus so
// that the endgame score with the correction will never be divided by more than two.
int eg = eg_value(positional_score);
int value = ((eg > 0) - (eg < 0)) * std::max( attacker_bonus , -abs( eg / 2 ) );
int value = ((eg > 0) - (eg < 0)) * std::max(attacker_bonus, -abs(eg / 2));
return make_score( 0 , value ) ;
return make_score(0, value);
}
} // namespace
@ -789,7 +776,7 @@ Value Eval::evaluate(const Position& pos) {
// Evaluate space for both sides, only during opening
if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 12222)
score += (evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei)) * Weights[Space];
// Evaluate initiative
score += evaluate_initiative(pos, ei, score);

2
src/movepick.cpp
View file

@ -127,7 +127,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h,
template<>
void MovePicker::score<CAPTURES>() {
// Winning and equal captures in the main search are ordered by MVV, preferring
// captures near our home rank. Suprisingly, this appears to perform slightly
// 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 main search we want to push captures with negative SEE values to the

2
src/pawns.cpp
View file

@ -243,7 +243,7 @@ Entry* probe(const Position& pos) {
e->key = key;
e->score = evaluate<WHITE>(pos, e) - evaluate<BLACK>(pos, e);
e->asymmetry = popcount<Max15>( e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK] );
e->asymmetry = popcount<Max15>(e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]);
return e;
}