X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=0a88c9f1ba37b07a3738800fea6d11f0c003ec09;hp=c9c9e5992dbaf83cca00876317e3c3d9456647a1;hb=893a08a8c2eac3c2e7d2216b51811cc7378e2239;hpb=c8589903777b6e0289640b43fae966ded442af48
diff --git a/src/pawns.cpp b/src/pawns.cpp
index c9c9e599..0a88c9f1 100644
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -18,6 +18,7 @@
along with this program. If not, see .
*/
+#include
#include
#include "bitboard.h"
@@ -35,8 +36,8 @@ namespace {
constexpr Score Doubled = S(11, 56);
constexpr Score Isolated = S( 5, 15);
- // Connected pawn bonus by opposed, phalanx, #support and rank
- Score Connected[2][2][3][RANK_NB];
+ // Connected pawn bonus
+ constexpr int Connected[RANK_NB] = { 0, 13, 17, 24, 59, 96, 171 };
// Strength of pawn shelter for our king by [distance from edge][rank].
// RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king.
@@ -77,11 +78,8 @@ namespace {
Bitboard theirPawns = pos.pieces(Them, PAWN);
e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0;
- e->semiopenFiles[Us] = 0xFF;
e->kingSquares[Us] = SQ_NONE;
e->pawnAttacks[Us] = pawn_attacks_bb(ourPawns);
- e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares);
- e->pawnsOnSquares[Us][WHITE] = pos.count(Us) - e->pawnsOnSquares[Us][BLACK];
// Loop through all pawns of the current color and score each pawn
while ((s = *pl++) != SQ_NONE)
@@ -89,8 +87,8 @@ namespace {
assert(pos.piece_on(s) == make_piece(Us, PAWN));
File f = file_of(s);
+ Rank r = relative_rank(Us, s);
- e->semiopenFiles[Us] &= ~(1 << f);
e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s);
// Flag the pawn
@@ -117,8 +115,7 @@ namespace {
&& popcount(phalanx) >= popcount(leverPush))
e->passedPawns[Us] |= s;
- else if ( stoppers == square_bb(s + Up)
- && relative_rank(Us, s) >= RANK_5)
+ else if (stoppers == square_bb(s + Up) && r >= RANK_5)
{
b = shift(support) & ~theirPawns;
while (b)
@@ -128,8 +125,11 @@ namespace {
// Score this pawn
if (support | phalanx)
- score += Connected[opposed][bool(phalanx)][popcount(support)][relative_rank(Us, s)];
-
+ {
+ int v = (phalanx ? 3 : 2) * Connected[r];
+ v = 17 * popcount(support) + (v >> (opposed + 1));
+ score += make_score(v, v * (r - 2) / 4);
+ }
else if (!neighbours)
score -= Isolated, e->weakUnopposed[Us] += !opposed;
@@ -147,27 +147,6 @@ namespace {
namespace Pawns {
-/// Pawns::init() initializes some tables needed by evaluation. Instead of using
-/// hard-coded tables, when makes sense, we prefer to calculate them with a formula
-/// to reduce independent parameters and to allow easier tuning and better insight.
-
-void init() {
-
- static constexpr int Seed[RANK_NB] = { 0, 13, 24, 18, 65, 100, 175, 330 };
-
- for (int opposed = 0; opposed <= 1; ++opposed)
- for (int phalanx = 0; phalanx <= 1; ++phalanx)
- for (int support = 0; support <= 2; ++support)
- for (Rank r = RANK_2; r < RANK_8; ++r)
- {
- int v = 17 * support;
- v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
-
- Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4);
- }
-}
-
-
/// Pawns::probe() looks up the current position's pawns configuration in
/// the pawns hash table. It returns a pointer to the Entry if the position
/// is found. Otherwise a new Entry is computed and stored there, so we don't
@@ -184,7 +163,6 @@ Entry* probe(const Position& pos) {
e->key = key;
e->scores[WHITE] = evaluate(pos, e);
e->scores[BLACK] = evaluate(pos, e);
- e->passedCount= popcount(e->passedPawns[WHITE] | e->passedPawns[BLACK]);
return e;
}
@@ -198,14 +176,14 @@ Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
- constexpr Bitboard BlockRanks = (Us == WHITE ? Rank1BB | Rank2BB : Rank8BB | Rank7BB);
+ constexpr Bitboard BlockSquares = (Rank1BB | Rank2BB | Rank7BB | Rank8BB)
+ & (FileABB | FileHBB);
Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, ksq);
Bitboard ourPawns = b & pos.pieces(Us);
Bitboard theirPawns = b & pos.pieces(Them);
- Value safety = (shift(theirPawns) & (FileABB | FileHBB) & BlockRanks & ksq) ?
- Value(374) : Value(5);
+ Value safety = (shift(theirPawns) & BlockSquares & ksq) ? Value(374) : Value(5);
File center = clamp(file_of(ksq), FILE_B, FILE_G);
for (File f = File(center - 1); f <= File(center + 1); ++f)
@@ -235,11 +213,15 @@ Score Entry::do_king_safety(const Position& pos) {
Square ksq = pos.square(Us);
kingSquares[Us] = ksq;
castlingRights[Us] = pos.castling_rights(Us);
- int minKingPawnDistance = 0;
Bitboard pawns = pos.pieces(Us, PAWN);
- if (pawns)
- while (!(DistanceRingBB[ksq][++minKingPawnDistance] & pawns)) {}
+ int minPawnDist = pawns ? 8 : 0;
+
+ if (pawns & PseudoAttacks[KING][ksq])
+ minPawnDist = 1;
+
+ else while (pawns)
+ minPawnDist = std::min(minPawnDist, distance(ksq, pop_lsb(&pawns)));
Value bonus = evaluate_shelter(pos, ksq);
@@ -250,7 +232,7 @@ Score Entry::do_king_safety(const Position& pos) {
if (pos.can_castle(Us | QUEEN_SIDE))
bonus = std::max(bonus, evaluate_shelter(pos, relative_square(Us, SQ_C1)));
- return make_score(bonus, -16 * minKingPawnDistance);
+ return make_score(bonus, -16 * minPawnDist);
}
// Explicit template instantiation