Retire pawn span

Stefano80 · mcostalba · commit 9585f8ef582b · 2016-08-18T10:16:56.000+02:00
Retire pawn span and replace with pawn count in evaluate_scale_factor.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 26482 W: 4929 L: 4818 D: 16735

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 61938 W: 8400 L: 8335 D: 45203

Bench: 7662861
diff --git a/src/evaluate.cpp b/src/evaluate.cpp
@@ -758,9 +758,9 @@ namespace {
         // Endings where weaker side can place his king in front of the opponent's
         // pawns are drawish.
         else if (    abs(eg) <= BishopValueEg
-                 &&  ei.pi->pawn_span(strongSide) <= 1
+                 &&  pos.count<PAWN>(strongSide) <= 2
                  && !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
-            sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(51) : ScaleFactor(37);
+            sf = ScaleFactor(37 + 7 * pos.count<PAWN>(strongSide));
     }
 
     return sf;
diff --git a/src/pawns.cpp b/src/pawns.cpp
@@ -173,8 +173,6 @@ namespace {
     }
 
     b = e->semiopenFiles[Us] ^ 0xFF;
-    e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0;
-
     return score;
   }
 
diff --git a/src/pawns.h b/src/pawns.h
@@ -37,7 +37,6 @@ struct Entry {
   Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
   Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
   Bitboard pawn_attacks_span(Color c) const { return pawnAttacksSpan[c]; }
-  int pawn_span(Color c) const { return pawnSpan[c]; }
   int pawn_asymmetry() const { return asymmetry; }
 
   int semiopen_file(Color c, File f) const {
@@ -73,7 +72,6 @@ struct Entry {
   Score kingSafety[COLOR_NB];
   int castlingRights[COLOR_NB];
   int semiopenFiles[COLOR_NB];
-  int pawnSpan[COLOR_NB];
   int pawnsOnSquares[COLOR_NB][COLOR_NB]; // [color][light/dark squares]
   int asymmetry;
 };

Original file line number	Diff line number	Diff line change
`@@ -173,8 +173,6 @@ namespace {`
`173`	`173`	`}`
`174`	`174`
`175`	`175`	`b = e->semiopenFiles[Us] ^ 0xFF;`
`176`		`- e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0;`
`177`		`-`
`178`	`176`	`return score;`
`179`	`177`	`}`
`180`	`178`