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Clarify difference between king zone and adjacent zone

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There are subtle differences in the king evaluation
that should be clear to avoid misunderstandings.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2008-09-25 15:08:41 +02:00
parent 453e815d4b
commit 2e3faae067
2 changed files with 23 additions and 20 deletions
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10
src/evaluate.cpp
View file

@ -501,7 +501,9 @@ void init_eval(int threads) {
/// quit_eval() releases heap-allocated memory at program termination. /// quit_eval() releases heap-allocated memory at program termination.
void quit_eval() { void quit_eval() {
for(int i = 0; i < THREAD_MAX; i++) {
for (int i = 0; i < THREAD_MAX; i++)
{
delete PawnTable[i]; delete PawnTable[i];
delete MaterialTable[i]; delete MaterialTable[i];
} }
@ -546,7 +548,7 @@ namespace {
ei.kingAttackersWeight[us] += AttackWeight; ei.kingAttackersWeight[us] += AttackWeight;
Bitboard bb = (b & ei.attackedBy[them][KING]); Bitboard bb = (b & ei.attackedBy[them][KING]);
if (bb) if (bb)
ei.kingZoneAttacksCount[us] += count_1s_max_15(bb); ei.kingAdjacentZoneAttacksCount[us] += count_1s_max_15(bb);
} }
// Mobility // Mobility
@ -717,7 +719,7 @@ namespace {
Color them = opposite_color(us); Color them = opposite_color(us);
if(p.queen_count(them) >= 1 && ei.kingAttackersCount[them] >= 2 if(p.queen_count(them) >= 1 && ei.kingAttackersCount[them] >= 2
&& p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame && p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame
&& ei.kingZoneAttacksCount[them]) { && ei.kingAdjacentZoneAttacksCount[them]) {
// Is it the attackers turn to move? // Is it the attackers turn to move?
bool sente = (them == p.side_to_move()); bool sente = (them == p.side_to_move());
@ -738,7 +740,7 @@ namespace {
// quality of the pawn shelter. // quality of the pawn shelter.
int attackUnits = int attackUnits =
Min((ei.kingAttackersCount[them] * ei.kingAttackersWeight[them]) / 2, 25) Min((ei.kingAttackersCount[them] * ei.kingAttackersWeight[them]) / 2, 25)
+ (ei.kingZoneAttacksCount[them] + count_1s_max_15(undefended)) * 3 + (ei.kingAdjacentZoneAttacksCount[them] + count_1s_max_15(undefended)) * 3
+ InitKingDanger[relative_square(us, s)] - shelter / 32; + InitKingDanger[relative_square(us, s)] - shelter / 32;
// Analyse safe queen contact checks: // Analyse safe queen contact checks:

21
src/evaluate.h
View file

@ -65,22 +65,23 @@ struct EvalInfo {
// f7, g7, h7, f6, g6 and h6. // f7, g7, h7, f6, g6 and h6.
Bitboard kingZone[2]; Bitboard kingZone[2];
// kingAttackersCount[color] is the number of pieces of the given color which // kingAttackersCount[color] is the number of pieces of the given color
// attack a square adjacent to the enemy king. // which attack a square in the kingZone of the enemy king.
int kingAttackersCount[2]; int kingAttackersCount[2];
// kingAttackersWeight[color] is the sum of the "weight" of the pieces of the // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
// given color which attack a square adjacent to the enemy king. The weights // given color which attack a square in the kingZone of the enemy king. The
// of the individual piece types are given by the variables QueenAttackWeight, // weights of the individual piece types are given by the variables
// RookAttackWeight, BishopAttackWeight and KnightAttackWeight in evaluate.cpp // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
// KnightAttackWeight in evaluate.cpp
int kingAttackersWeight[2]; int kingAttackersWeight[2];
// kingZoneAttacksCount[color] is the number of attacks to squares directly // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
// adjacent to the king of the given color. Pieces which attack more // directly adjacent to the king of the given color. Pieces which attack
// than one square are counted multiple times. For instance, if black's // more than one square are counted multiple times. For instance, if black's
// king is on g8 and there's a white knight on g5, this knight adds // king is on g8 and there's a white knight on g5, this knight adds
// 2 to kingZoneAttacksCount[BLACK]. // 2 to kingAdjacentZoneAttacksCount[BLACK].
int kingZoneAttacksCount[2]; int kingAdjacentZoneAttacksCount[2];
// mateThreat[color] is a move for the given side which gives a direct mate. // mateThreat[color] is a move for the given side which gives a direct mate.
Move mateThreat[2]; Move mateThreat[2];