HCha/Stockfish
1
0
Fork 0
mirror of https://github.com/HChaZZY/Stockfish.git synced 2025-12-24 02:57:11 +08:00
Code Issues Packages Projects Releases Wiki Activity

Simplify scale factor computation

Browse Source 
Minor non-functional simplifications in computing the scale factor.

In my opinion, the code is now slightly more readable:

- remove one condition which can never be satisfied.
- immediately return instead of assigning the sf variable.

Tested for non-regression:

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 62162 W: 11166 L: 11115 D: 39881

No functional change

Closes #992
This commit is contained in:
Stefano80
2017-02-05 16:02:02 -08:00
committed by Joona Kiiski
parent 0553b46829
commit 5205d44f87
1 changed files with 4 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
src/evaluate.cpp
View File

@@ -755,8 +755,7 @@ namespace {
// If we don't already have an unusual scale factor, check for certain // If we don't already have an unusual scale factor, check for certain
// types of endgames, and use a lower scale for those. // types of endgames, and use a lower scale for those.
if ( ei.me->game_phase() < PHASE_MIDGAME if (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN)
&& (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
{ {
if (pos.opposite_bishops()) if (pos.opposite_bishops())
{ {
@@ -764,19 +763,18 @@ namespace {
// is almost a draw, in case of KBP vs KB, it is even more a draw. // is almost a draw, in case of KBP vs KB, it is even more a draw.
if ( pos.non_pawn_material(WHITE) == BishopValueMg if ( pos.non_pawn_material(WHITE) == BishopValueMg
&& pos.non_pawn_material(BLACK) == BishopValueMg) && pos.non_pawn_material(BLACK) == BishopValueMg)
sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9); return more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9);
// Endgame with opposite-colored bishops, but also other pieces. Still // Endgame with opposite-colored bishops, but also other pieces. Still
// a bit drawish, but not as drawish as with only the two bishops. // a bit drawish, but not as drawish as with only the two bishops.
else return ScaleFactor(46);
sf = ScaleFactor(46);
} }
// Endings where weaker side can place his king in front of the opponent's // Endings where weaker side can place his king in front of the opponent's
// pawns are drawish. // pawns are drawish.
else if ( abs(eg) <= BishopValueEg else if ( abs(eg) <= BishopValueEg
&& pos.count<PAWN>(strongSide) <= 2 && pos.count<PAWN>(strongSide) <= 2
&& !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide))) && !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
sf = ScaleFactor(37 + 7 * pos.count<PAWN>(strongSide)); return ScaleFactor(37 + 7 * pos.count<PAWN>(strongSide));
} }
return sf; return sf;