HCha/Stockfish
1
0
Fork 0
mirror of https://github.com/HChaZZY/Stockfish.git synced 2025-12-23 18:46:59 +08:00
Code Issues Packages Projects Releases Wiki Activity

Add Tord's polynomial material balance

Browse Source 
Use a polynomial weighted evaluation to calculate
material value.

This is far more flexible and elegant then applying
a series of single euristic rules as before.

Also correct a design issue in which we returned two
values, one for middle game and one for endgame, while
instead, because game phase is a function of board
material itself, only one value should be calculated and
used both for mid and end game.

Verified it is equivalent to the tuning branch results with
parameter values sampled after 40.000 games.

After 999 games at 1+0

Mod vs Orig +277 =482 -240 51.85%  518.0/999  +13 ELO

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2009-07-20 09:56:21 +01:00
parent 5600d91cff
commit 044ad593b3
3 changed files with 52 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
src/material.h
View File

@@ -51,8 +51,7 @@ class MaterialInfo {
public:
MaterialInfo() : key(0) { clear(); }
Value mg_value() const;
Value eg_value() const;
Value material_value() const;
ScaleFactor scale_factor(const Position& pos, Color c) const;
int space_weight() const;
bool specialized_eval_exists() const;
@@ -62,8 +61,7 @@ private:
inline void clear();
Key key;
int16_t mgValue;
int16_t egValue;
int16_t value;
uint8_t factor[2];
EndgameEvaluationFunctionBase* evaluationFunction;
EndgameScalingFunctionBase* scalingFunction[2];
@@ -102,17 +100,12 @@ private:
//// Inline functions
////
/// MaterialInfo::mg_value and MaterialInfo::eg_value simply returns the
/// material balance evaluation for the middle game and the endgame.
/// MaterialInfo::material_value simply returns the material balance
/// evaluation that is independent from game phase.
inline Value MaterialInfo::mg_value() const {
inline Value MaterialInfo::material_value() const {
return Value(mgValue);
}
inline Value MaterialInfo::eg_value() const {
return Value(egValue);
return Value(value);
}
@@ -121,7 +114,7 @@ inline Value MaterialInfo::eg_value() const {
inline void MaterialInfo::clear() {
mgValue = egValue = 0;
value = 0;
factor[WHITE] = factor[BLACK] = uint8_t(SCALE_FACTOR_NORMAL);
evaluationFunction = NULL;
scalingFunction[WHITE] = scalingFunction[BLACK] = NULL;