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Remove opposed flag for doubled pawns

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Actually, it is not used, as both arrays have the
same values. Some local tests in either direction
showed no improvement.

Also some minor corrections in the comments.

No functional change.
This commit is contained in:
Jörg Oster
2013-11-10 15:24:32 +01:00
committed by Marco Costalba
parent 1d18647e73
commit 4ef6b2c32a
1 changed files with 12 additions and 15 deletions
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src/pawns.cpp
+12 -15
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@@ -30,26 +30,24 @@ namespace {
#define V Value #define V Value
#define S(mg, eg) make_score(mg, eg) #define S(mg, eg) make_score(mg, eg)
// Doubled pawn penalty by opposed flag and file // Doubled pawn penalty by file
const Score Doubled[2][FILE_NB] = { const Score Doubled[FILE_NB] = {
{ S(13, 43), S(20, 48), S(23, 48), S(23, 48), S(13, 43), S(20, 48), S(23, 48), S(23, 48),
S(23, 48), S(23, 48), S(20, 48), S(13, 43) }, S(23, 48), S(23, 48), S(20, 48), S(13, 43) };
{ S(13, 43), S(20, 48), S(23, 48), S(23, 48),
S(23, 48), S(23, 48), S(20, 48), S(13, 43) }};
// Isolated pawn penalty by opposed flag and file // Isolated pawn penalty by opposed flag and file
const Score Isolated[2][FILE_NB] = { const Score Isolated[2][FILE_NB] = {
{ S(37, 45), S(54, 52), S(60, 52), S(60, 52), { S(37, 45), S(54, 52), S(60, 52), S(60, 52),
S(60, 52), S(60, 52), S(54, 52), S(37, 45) }, S(60, 52), S(60, 52), S(54, 52), S(37, 45) },
{ S(25, 30), S(36, 35), S(40, 35), S(40, 35), { S(25, 30), S(36, 35), S(40, 35), S(40, 35),
S(40, 35), S(40, 35), S(36, 35), S(25, 30) }}; S(40, 35), S(40, 35), S(36, 35), S(25, 30) } };
// Backward pawn penalty by opposed flag and file // Backward pawn penalty by opposed flag and file
const Score Backward[2][FILE_NB] = { const Score Backward[2][FILE_NB] = {
{ S(30, 42), S(43, 46), S(49, 46), S(49, 46), { S(30, 42), S(43, 46), S(49, 46), S(49, 46),
S(49, 46), S(49, 46), S(43, 46), S(30, 42) }, S(49, 46), S(49, 46), S(43, 46), S(30, 42) },
{ S(20, 28), S(29, 31), S(33, 31), S(33, 31), { S(20, 28), S(29, 31), S(33, 31), S(33, 31),
S(33, 31), S(33, 31), S(29, 31), S(20, 28) }}; S(33, 31), S(33, 31), S(29, 31), S(20, 28) } };
// Pawn chain membership bonus by file and rank (initialized by formula) // Pawn chain membership bonus by file and rank (initialized by formula)
Score ChainMember[FILE_NB][RANK_NB]; Score ChainMember[FILE_NB][RANK_NB];
@@ -57,8 +55,7 @@ namespace {
// Candidate passed pawn bonus by rank // Candidate passed pawn bonus by rank
const Score CandidatePassed[RANK_NB] = { const Score CandidatePassed[RANK_NB] = {
S( 0, 0), S( 6, 13), S(6,13), S(14,29), S( 0, 0), S( 6, 13), S(6,13), S(14,29),
S(34,68), S(83,166), S(0, 0), S( 0, 0) S(34,68), S(83,166), S(0, 0), S( 0, 0) };
};
// Weakness of our pawn shelter in front of the king indexed by [rank] // Weakness of our pawn shelter in front of the king indexed by [rank]
const Value ShelterWeakness[RANK_NB] = const Value ShelterWeakness[RANK_NB] =
@@ -69,10 +66,10 @@ namespace {
const Value StormDanger[3][RANK_NB] = { const Value StormDanger[3][RANK_NB] = {
{ V( 0), V(64), V(128), V(51), V(26) }, { V( 0), V(64), V(128), V(51), V(26) },
{ V(26), V(32), V( 96), V(38), V(20) }, { V(26), V(32), V( 96), V(38), V(20) },
{ V( 0), V( 0), V( 64), V(25), V(13) }}; { V( 0), V( 0), V( 64), V(25), V(13) } };
// Max bonus for king safety. Corresponds to start position with all the pawns // Max bonus for king safety. Corresponds to start position with all the pawns
// in front of the king and no enemy pawn on the horizont. // in front of the king and no enemy pawn on the horizon.
const Value MaxSafetyBonus = V(263); const Value MaxSafetyBonus = V(263);
#undef S #undef S
@@ -148,7 +145,7 @@ namespace {
assert(opposed | passed | (pawn_attack_span(Us, s) & theirPawns)); assert(opposed | passed | (pawn_attack_span(Us, s) & theirPawns));
// A not passed pawn is a candidate to become passed if it is free to // A not passed pawn is a candidate to become passed, if it is free to
// advance and if the number of friendly pawns beside or behind this // advance and if the number of friendly pawns beside or behind this
// pawn on adjacent files is higher or equal than the number of // pawn on adjacent files is higher or equal than the number of
// enemy pawns in the forward direction on the adjacent files. // enemy pawns in the forward direction on the adjacent files.
@@ -167,7 +164,7 @@ namespace {
value -= Isolated[opposed][f]; value -= Isolated[opposed][f];
if (doubled) if (doubled)
value -= Doubled[opposed][f]; value -= Doubled[f];
if (backward) if (backward)
value -= Backward[opposed][f]; value -= Backward[opposed][f];
@@ -274,7 +271,7 @@ Score Entry::update_safety(const Position& pos, Square ksq) {
Value bonus = shelter_storm<Us>(pos, ksq); Value bonus = shelter_storm<Us>(pos, ksq);
// If we can castle use the bonus after the castle if is bigger // If we can castle use the bonus after the castle if it is bigger
if (pos.can_castle(make_castle_right(Us, KING_SIDE))) if (pos.can_castle(make_castle_right(Us, KING_SIDE)))
bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1))); bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1)));