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Aryan1508Aryan1508
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Pawn shield (#114)
ELO | 5.38 +- 4.20 (95%) SPRT | 10.0+0.10s Threads=1 Hash=16MB LLR | 3.00 (-2.94, 2.94) [0.00, 5.00] GAMES | N: 15752 W: 4846 L: 4602 D: 6304 Bench: 8152978
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7 files changed

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‎Bit-Genie/src/bitmask.h‎

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@@ -82,6 +82,46 @@ namespace BitMask
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0X2838000000000000, 0X5070000000000000, 0Xa0e0000000000000, 0X40c0000000000000
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};
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constexpr uint64_t pawn_shield[total_colors][total_squares]
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{
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{
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0x0000000000000300, 0x0000000000000700, 0x0000000000000e00, 0x0000000000001c00,
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0x0000000000003800, 0x0000000000007000, 0x000000000000e000, 0x000000000000c000,
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0x0000000000030000, 0x0000000000070000, 0x00000000000e0000, 0x00000000001c0000,
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0x0000000000380000, 0x0000000000700000, 0x0000000000e00000, 0x0000000000c00000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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},
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{
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
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0x0000030000000000, 0x0000070000000000, 0x00000e0000000000, 0x00001c0000000000,
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0x0000380000000000, 0x0000700000000000, 0x0000e00000000000, 0x0000c00000000000,
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0x0003000000000000, 0x0007000000000000, 0x000e000000000000, 0x001c000000000000,
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0x0038000000000000, 0x0070000000000000, 0x00e0000000000000, 0x00c0000000000000,
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},
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};
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constexpr uint64_t pawn_attacks[total_colors][total_squares]{
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{
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0X000000000000000200, 0X000000000000000500, 0X000000000000000a00, 0X000000000000001400,

‎Bit-Genie/src/eval.cpp‎

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Original file line numberDiff line numberDiff line change
@@ -363,6 +363,7 @@ int get_phase(Position const &position)
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static int evaluate_king(Position const &position, EvalData &data, Square sq, Color us)
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{
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Square relative_sq = psqt_sq(sq, us);
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uint64_t friend_pawns = position.pieces.get_piece_bb<Pawn>(us);
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int score = KingEval::psqt[relative_sq];
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TRACE_3(psqt, King, relative_sq);
@@ -382,6 +383,10 @@ static int evaluate_king(Position const &position, EvalData &data, Square sq, Co
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TRACE_2(safety_table, weight);
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}
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int shield_pawn_count = popcount64(friend_pawns & BitMask::pawn_shield[us][sq]);
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score += KingEval::pawn_shield[shield_pawn_count];
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TRACE_2(pawn_shield, shield_pawn_count);
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return score;
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}
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