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Consolidate pawn storm types

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Simplification: the Unopposed and Unblocked pawn storm types are mathematically
similar enough to combine with no Elo loss. This reduces the pawn storm types
to BlockedByPawn and UnBlocked.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 116869 W: 23549 L: 23605 D: 69715
http://tests.stockfishchess.org/tests/view/5af2def90ebc5968e6523f82

LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 39912 W: 6090 L: 5998 D: 27824
http://tests.stockfishchess.org/tests/view/5af3b2e20ebc5968e6524013

Closes https://github.com/official-stockfish/Stockfish/pull/1592

Bench: 5244314
This commit is contained in:
protonspring 2018-05-10 15:46:13 +02:00 • committed by Stéphane Nicolet
parent 76d4a80084
commit 255df4ffae
1 changed files with 15 additions and 19 deletions
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34
src/pawns.cpp
View file

@ -53,21 +53,17 @@ namespace {
};
// Danger of enemy pawns moving toward our king by [type][distance from edge][rank].
// For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has
// no pawn on the given file, or their pawn is behind our king.
// For the unblocked case, RANK_1 = 0 is used when opponent has no pawn on the
// given file, or their pawn is behind our king.
constexpr Value StormDanger[][4][RANK_NB] = {
{ { V(11), V( 79), V(132), V( 68), V( 33) }, // Unopposed
{ V( 4), V(104), V(155), V( 4), V( 21) },
{ V(-7), V( 59), V(142), V( 45), V( 30) },
{ V( 0), V( 62), V(113), V( 43), V( 13) } },
{ { V(25), V( 79), V(107), V( 51), V( 27) }, // UnBlocked
{ V(15), V( 45), V(131), V( 8), V( 25) },
{ V( 0), V( 42), V(118), V( 56), V( 27) },
{ V( 3), V( 54), V(110), V( 55), V( 26) } },
{ { V( 0), V( 0), V( 37), V( 5), V(-48) }, // BlockedByPawn
{ V( 0), V( 0), V( 68), V(-12), V( 13) },
{ V( 0), V( 0), V(111), V(-25), V( -3) },
{ V( 0), V( 0), V(108), V( 14), V( 21) } },
{ { V(38), V( 78), V( 83), V( 35), V( 22) }, // Unblocked
{ V(33), V(-15), V(108), V( 12), V( 28) },
{ V( 8), V( 25), V( 94), V( 68), V( 25) },
{ V( 6), V( 48), V(120), V( 68), V( 40) } }
{ V( 0), V( 0), V(108), V( 14), V( 21) } }
};
#undef S
@ -212,7 +208,7 @@ Entry* probe(const Position& pos) {
template<Color Us>
Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
enum { Unopposed, BlockedByPawn, Unblocked };
enum { UnBlocked, BlockedByPawn };
constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
constexpr Bitboard BlockRanks = (Us == WHITE ? Rank1BB | Rank2BB : Rank8BB | Rank7BB);
@ -224,22 +220,22 @@ Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
Value safety = (ourPawns & file_bb(ksq)) ? Value(5) : Value(-5);
if (shift<Down>(theirPawns) & (FileABB | FileHBB) & BlockRanks & ksq)
safety += 374;
safety += Value(374);
File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
for (File f = File(center - 1); f <= File(center + 1); ++f)
{
b = ourPawns & file_bb(f);
Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
int ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : 0;
b = theirPawns & file_bb(f);
Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
int d = std::min(f, ~f);
safety += ShelterStrength[d][rkUs]
- StormDanger[rkUs == RANK_1 ? Unopposed :
rkUs == rkThem - 1 ? BlockedByPawn : Unblocked]
[d][rkThem];
safety += ShelterStrength[d][ourRank];
if (ourRank || theirRank)
safety -= StormDanger[ourRank && (ourRank == theirRank - 1) ? BlockedByPawn : UnBlocked][d][theirRank];
}
return safety;