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Avoid a call to apply_weight() in evaluate_king()

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Precompute scores in SafetyTable[] instead of calculate
them on the fly.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2010-05-01 05:41:25 +01:00
parent 8e269d781a
commit fe76787a77
1 changed files with 18 additions and 13 deletions
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31
src/evaluate.cpp
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@ -251,9 +251,8 @@ namespace {
15, 15, 15, 15, 15, 15, 15, 15
};
// SafetyTable[] contains the actual king safety scores. It is initialized
// in init_safety().
Value SafetyTable[100];
// SafetyTable[color][] contains the actual king safety weighted scores
Score SafetyTable[2][128];
// Pawn and material hash tables, indexed by the current thread id.
// Note that they will be initialized at 0 being global variables.
@ -869,9 +868,8 @@ namespace {
// that the king safety 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.
Score v = apply_weight(make_score(SafetyTable[attackUnits], 0), WeightKingSafety[Us]);
ei.value -= Sign[Us] * v;
ei.futilityMargin[Us] += mg_value(v);
ei.value -= Sign[Us] * SafetyTable[Us][attackUnits];
ei.futilityMargin[Us] += mg_value(SafetyTable[Us][attackUnits]);
}
}
@ -1204,7 +1202,7 @@ namespace {
}
// init_safety() initizes the king safety evaluation, based on UCI
// parameters. It is called from read_weights().
// parameters. It is called from read_weights().
void init_safety() {
@ -1212,22 +1210,29 @@ namespace {
int peak = 0x500;
double a = 0.4;
double b = 0.0;
Value t[100];
// First setup the base table
for (int i = 0; i < 100; i++)
{
if (i < b)
SafetyTable[i] = Value(0);
t[i] = Value(0);
else
SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
t[i] = Value((int)(a * (i - b) * (i - b)));
}
for (int i = 1; i < 100; i++)
{
if (SafetyTable[i] - SafetyTable[i - 1] > maxSlope)
SafetyTable[i] = SafetyTable[i - 1] + Value(maxSlope);
if (t[i] - t[i - 1] > maxSlope)
t[i] = t[i - 1] + Value(maxSlope);
if (SafetyTable[i] > Value(peak))
SafetyTable[i] = Value(peak);
if (t[i] > Value(peak))
t[i] = Value(peak);
}
// Then apply the weights and get the final SafetyTable[] 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), WeightKingSafety[c]);
}
}