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join scale_factor, initiative and mg+eg reduction

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Merging this code into one function `winnable()`.
Should allow common concepts used to adjust the eg value,
either by addition or scaling, to be combined more effectively.

Improve trace function.

closes https://github.com/official-stockfish/Stockfish/pull/2710

No functional change.
This commit is contained in:
xoto10 2020-06-03 11:05:58 +01:00 • committed by Joost VandeVondele
parent 15e190e942
commit 902309020a
1 changed files with 25 additions and 29 deletions
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54
src/evaluate.cpp
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@ -35,7 +35,7 @@ namespace Trace {
enum Tracing { NO_TRACE, TRACE };
enum Term { // The first 8 entries are reserved for PieceType
MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, INITIATIVE, TOTAL, TERM_NB
MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, WINNABLE, TOTAL, TERM_NB
};
Score scores[TERM_NB][COLOR_NB];
@ -59,7 +59,7 @@ namespace Trace {
std::ostream& operator<<(std::ostream& os, Term t) {
if (t == MATERIAL || t == IMBALANCE || t == INITIATIVE || t == TOTAL)
if (t == MATERIAL || t == IMBALANCE || t == WINNABLE || t == TOTAL)
os << " ---- ----" << " | " << " ---- ----";
else
os << scores[t][WHITE] << " | " << scores[t][BLACK];
@ -173,8 +173,7 @@ namespace {
template<Color Us> Score threats() const;
template<Color Us> Score passed() const;
template<Color Us> Score space() const;
ScaleFactor scale_factor(Value eg) const;
Score initiative(Score score) const;
Value winnable(Score score) const;
const Position& pos;
Material::Entry* me;
@ -717,12 +716,12 @@ namespace {
}
// Evaluation::initiative() computes the initiative correction value
// for the position. It is a second order bonus/malus based on the
// Evaluation::winnable() adjusts the mg and eg score components based on the
// known attacking/defending status of the players.
// A single value is derived from the mg and eg values and returned.
template<Tracing T>
Score Evaluation<T>::initiative(Score score) const {
Value Evaluation<T>::winnable(Score score) const {
int outflanking = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
- distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
@ -756,17 +755,10 @@ namespace {
int u = ((mg > 0) - (mg < 0)) * Utility::clamp(complexity + 50, -abs(mg), 0);
int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));
if (T)
Trace::add(INITIATIVE, make_score(u, v));
mg += u;
eg += v;
return make_score(u, v);
}
// Evaluation::scale_factor() computes the scale factor for the winning side
template<Tracing T>
ScaleFactor Evaluation<T>::scale_factor(Value eg) const {
// Compute the scale factor for the winning side
Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
int sf = me->scale_factor(pos, strongSide);
@ -786,7 +778,18 @@ namespace {
sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide));
}
return ScaleFactor(sf);
// Interpolate between the middlegame and (scaled by 'sf') endgame score
v = mg * int(me->game_phase())
+ eg * int(PHASE_MIDGAME - me->game_phase()) * ScaleFactor(sf) / SCALE_FACTOR_NORMAL;
v /= PHASE_MIDGAME;
if (T)
{
Trace::add(WINNABLE, make_score(u, eg * ScaleFactor(sf) / SCALE_FACTOR_NORMAL - eg_value(score)));
Trace::add(TOTAL, make_score(mg, eg * ScaleFactor(sf) / SCALE_FACTOR_NORMAL));
}
return Value(v);
}
@ -841,14 +844,8 @@ namespace {
+ passed< WHITE>() - passed< BLACK>()
+ space< WHITE>() - space< BLACK>();
score += initiative(score);
// Interpolate between a middlegame and a (scaled by 'sf') endgame score
ScaleFactor sf = scale_factor(eg_value(score));
v = mg_value(score) * int(me->game_phase())
+ eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
v /= PHASE_MIDGAME;
// Derive single value from mg and eg parts of score
v = winnable(score);
// In case of tracing add all remaining individual evaluation terms
if (T)
@ -857,7 +854,6 @@ namespace {
Trace::add(IMBALANCE, me->imbalance());
Trace::add(PAWN, pe->pawn_score(WHITE), pe->pawn_score(BLACK));
Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
Trace::add(TOTAL, score);
}
// Side to move point of view
@ -909,11 +905,11 @@ std::string Eval::trace(const Position& pos) {
<< " Threats | " << Term(THREAT)
<< " Passed | " << Term(PASSED)
<< " Space | " << Term(SPACE)
<< " Initiative | " << Term(INITIATIVE)
<< " Winnable | " << Term(WINNABLE)
<< " ------------+-------------+-------------+------------\n"
<< " Total | " << Term(TOTAL);
ss << "\nTotal evaluation: " << to_cp(v) << " (white side)\n";
ss << "\nFinal evaluation: " << to_cp(v) << " (white side)\n";
return ss.str();
}