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Bonus for reachable outpost

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Give a bonus for outpost squares which in reach of a bishop or knight.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 22725 W: 4570 L: 4339 D: 13816

LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 15019 W: 2333 L: 2157 D: 10529

Bench: 8503181

Resolves #495
This commit is contained in:
Stefan Geschwentner
2015-11-14 06:30:50 -08:00
committed by Joona Kiiski
parent 76ed0ab501
commit cccf3c815c
3 changed files with 28 additions and 7 deletions
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29
src/evaluate.cpp
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@@ -141,6 +141,11 @@ namespace {
S(112,125), S(113,127), S(117,137), S(122,143) }
};
// Mask of allowed outpost squares indexed by color
const Bitboard OutpostMask[COLOR_NB] = {
Rank4BB | Rank5BB | Rank6BB, Rank5BB | Rank4BB | Rank3BB
};
// Outpost[knight/bishop][supported by pawn] contains bonuses for knights and
// bishops outposts, bigger if outpost piece is supported by a pawn.
const Score Outpost[][2] = {
@@ -148,6 +153,13 @@ namespace {
{ S(18, 5), S(27, 8) } // Bishops
};
// ReachableOutpost[knight/bishop][supported by pawn] contains bonuses for knights and
// bishops which can reach a outpost square in one move, bigger if outpost square is supported by a pawn.
const Score ReachableOutpost[][2] = {
{ S(21, 5), S(31, 8) }, // Knights
{ S( 8, 2), S(13, 4) } // Bishops
};
// Threat[minor/rook][attacked PieceType] contains
// bonuses according to which piece type attacks which one.
// Attacks on lesser pieces which are pawn defended are not considered.
@@ -257,7 +269,7 @@ namespace {
template<PieceType Pt, Color Us, bool DoTrace>
Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, const Bitboard* mobilityArea) {
Bitboard b;
Bitboard b, bb;
Square s;
Score score = SCORE_ZERO;
@@ -283,7 +295,7 @@ namespace {
{
ei.kingAttackersCount[Us]++;
ei.kingAttackersWeight[Us] += KingAttackWeights[Pt];
Bitboard bb = b & ei.attackedBy[Them][KING];
bb = b & ei.attackedBy[Them][KING];
if (bb)
ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
}
@@ -299,11 +311,16 @@ namespace {
if (Pt == BISHOP || Pt == KNIGHT)
{
// Bonus for outpost square
if ( relative_rank(Us, s) >= RANK_4
&& relative_rank(Us, s) <= RANK_6
&& !(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
// Bonus for outpost squares
bb = OutpostMask[Us] & ~ei.pi->pawn_attacks_span(Them);
if (bb & s)
score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)];
else
{
bb &= b & ~pos.pieces(Us);
if (bb)
score += ReachableOutpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)];
}
// Bonus when behind a pawn
if ( relative_rank(Us, s) < RANK_5