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Code Issues Releases Wiki Activity

Rename king "safety" to king "danger"

Browse source 
A bigger "safety" value is actually a bigger
threat for the king, so it is a bigger "danger"

With this renaming "Cowardice" and "Aggressiveness"
UCI parameters become easier to understand.

It is also easier to understand why the once "safety"
value (that is a "danger") is subtracted from evaluation
instead of being added.

No functional change.
This commit is contained in:
Marco Costalba 2010-05-06 10:36:01 +02:00
parent 569bc75eb8
commit 921bd87280
1 changed files with 26 additions and 26 deletions
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52
src/evaluate.cpp
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@ -46,7 +46,7 @@ namespace {
const int GrainSize = 8;
// Evaluation weights, initialized from UCI options
enum { Mobility, PawnStructure, PassedPawns, Space, KingSafetyUs, KingSafetyThem };
enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
Score Weights[6];
typedef Value V;
@ -203,10 +203,10 @@ namespace {
(1ULL<<SQ_C5) | (1ULL<<SQ_D5) | (1ULL<<SQ_E5) | (1ULL<<SQ_F5)
};
/// King safety constants and variables. The king safety scores are taken
/// from the array SafetyTable[]. Various little "meta-bonuses" measuring
/// the strength of the attack are added up into an integer, which is used
/// as an index to SafetyTable[].
/// King danger constants and variables. The king danger scores are taken
/// from the KingDangerTable[]. Various little "meta-bonuses" measuring
/// the strength of the enemy attack are added up into an integer, which
/// is used as an index to KingDangerTable[].
// Attack weights for each piece type and table indexed on piece type
const int QueenAttackWeight = 5;
@ -243,8 +243,8 @@ namespace {
15, 15, 15, 15, 15, 15, 15, 15
};
// SafetyTable[color][] contains the actual king safety weighted scores
Score SafetyTable[2][128];
// KingDangerTable[color][] contains the actual king danger weighted scores
Score KingDangerTable[2][128];
// Pawn and material hash tables, indexed by the current thread id.
// Note that they will be initialized at 0 being global variables.
@ -479,22 +479,22 @@ void quit_eval() {
void read_weights(Color us) {
// King safety is asymmetrical. Our king safety is controled by "Cowardice"
// UCI parameter, instead the opponent one by "Aggressiveness".
const int kingSafetyUs = (us == WHITE ? KingSafetyUs : KingSafetyThem);
const int kingSafetyThem = (us == WHITE ? KingSafetyThem : KingSafetyUs);
// King safety is asymmetrical. Our king danger level is weighted by
// "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
Weights[kingSafetyUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingSafetyUs]);
Weights[kingSafetyThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingSafetyThem]);
Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
// If running in analysis mode, make sure we use symmetrical king safety. We do this
// by replacing both Weights[kingSafetyUs] and Weights[kingSafetyThem] by their average.
// by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
if (get_option_value_bool("UCI_AnalyseMode"))
Weights[kingSafetyUs] = Weights[kingSafetyThem] = (Weights[kingSafetyUs] + Weights[kingSafetyThem]) / 2;
Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
init_safety();
}
@ -736,10 +736,10 @@ namespace {
| ei.attacked_by(Us, QUEEN));
// Initialize the 'attackUnits' variable, which is used later on as an
// index to the SafetyTable[] array. The initial value is based on the
// number and types of the attacking pieces, the number of attacked and
// undefended squares around the king, the square of the king, and the
// quality of the pawn shelter.
// index to the KingDangerTable[] array. The initial value is based on
// the number and types of the enemy's attacking pieces, the number of
// attacked and undefended squares around our king, the square of the
// king, and the quality of the pawn shelter.
attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
+ 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended))
+ InitKingDanger[relative_square(Us, s)]
@ -855,14 +855,14 @@ namespace {
// out of bounds errors.
attackUnits = Min(99, Max(0, attackUnits));
// Finally, extract the king safety score from the SafetyTable[] array.
// Finally, extract the king danger score from the KingDangerTable[] array.
// Subtract the score from evaluation, and set ei.futilityMargin[].
// The reason for storing the king safety score to futility margin
// is that the king safety scores can sometimes be very big, and that
// The reason for storing the king danger score to futility margin
// is that the king danger scores can sometimes be very big, and that
// capturing a single attacking piece can therefore result in a score
// change far bigger than the value of the captured piece.
ei.value -= Sign[Us] * SafetyTable[Us][attackUnits];
ei.futilityMargin[Us] = mg_value(SafetyTable[Us][attackUnits]);
ei.value -= Sign[Us] * KingDangerTable[Us][attackUnits];
ei.futilityMargin[Us] = mg_value(KingDangerTable[Us][attackUnits]);
}
}
@ -1223,9 +1223,9 @@ namespace {
t[i] = Value(peak);
}
// Then apply the weights and get the final SafetyTable[] array
// Then apply the weights and get the final KingDangerTable[] array
for (Color c = WHITE; c <= BLACK; c++)
for (int i = 0; i < 100; i++)
SafetyTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingSafetyUs + c]);
KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
}
}