From 9585f8ef582bc317f61534503a76563dedd247fa Mon Sep 17 00:00:00 2001
From: Stefano80 <stefano.cardanobile@gmail.com>
Date: Mon, 15 Aug 2016 12:24:48 +0200
Subject: [PATCH] Retire pawn span

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
---
 src/evaluate.cpp | 4 ++--
 src/pawns.cpp    | 2 --
 src/pawns.h      | 2 --
 3 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index d3ddfd51..664847ad 100644
--- 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
index 23d00bde..41127d1f 100644
--- 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
index c2f5fc0d..24843e30 100644
--- 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;
 };
-- 
2.39.2