From 44a571c1c7494503ee431ef6f974d030bf96af0d Mon Sep 17 00:00:00 2001
From: hxim <hxim.jo@gmail.com>
Date: Mon, 9 Feb 2015 19:12:04 +0100
Subject: [PATCH 1/2] Fix KingDanger[] array initialization

Use integer arithmetic instead of floating point arithmetic.
Floating point arithmetic was causing different results for some 32-bit compiles

No functional change

Resolves #249
Resolves #250
---
 src/evaluate.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index be3c6497..40d59648 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -912,14 +912,14 @@ namespace Eval {
 
   void init() {
 
-    const double MaxSlope = 8.7;
-    const double Peak = 1280;
-    double t = 0.0;
+    const int MaxSlope = 87;
+    const int Peak = 12800;
+    int t = 0;
 
-    for (int i = 1; i < 400; ++i)
+    for (int i = 0; i < 400; ++i)
     {
-        t = std::min(Peak, std::min(0.027 * i * i, t + MaxSlope));
-        KingDanger[i] = apply_weight(make_score(int(t), 0), Weights[KingSafety]);
+        t = std::min(Peak, std::min(i * i * 27 / 100, t + MaxSlope));
+        KingDanger[i] = apply_weight(make_score(t / 10, 0), Weights[KingSafety]);
     }
   }
 

From a8f9c7a790883d2d31e108cd2739aefcfa5d919e Mon Sep 17 00:00:00 2001
From: snicolet <cassio@free.fr>
Date: Fri, 13 Feb 2015 21:33:00 +0000
Subject: [PATCH 2/2] Small bonus for all safe pawn pushes

Pawn flexibility: add a small bonus for all safe pawn pushes

STC:
LLR: 2.70 (-2.94,2.94) [-1.50,4.50]
Total: 18233 W: 3705 L: 3557 D: 10971

LTC:
LLR: 2.97 (-2.94,2.94) [0.00,6.00]
Total: 17684 W: 3042 L: 2854 D: 11788

Bench: 7369224

Resolves #253
---
 src/evaluate.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 40d59648..9d19ad75 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -163,6 +163,7 @@ namespace {
   const Score Unstoppable        = S( 0, 20);
   const Score Hanging            = S(31, 26);
   const Score PawnAttackThreat   = S(20, 20);
+  const Score PawnSafePush       = S( 5 , 5);
 
   // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
   // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
@@ -547,14 +548,18 @@ namespace {
             score += more_than_one(b) ? KingOnMany : KingOnOne;
     }
 
-    // Add bonus for safe pawn pushes which attacks an enemy piece
+    // Add a small bonus for safe pawn pushes
     b = pos.pieces(Us, PAWN) & ~TRank7BB;
     b = shift_bb<Up>(b | (shift_bb<Up>(b & TRank2BB) & ~pos.pieces()));
 
     b &=  ~pos.pieces()
         & ~ei.attackedBy[Them][PAWN]
-        & (ei.attackedBy[Us][PAWN] | ~ei.attackedBy[Them][ALL_PIECES]);
+        & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
+    
+    if (b)
+        score += popcount<Full>(b) * PawnSafePush;
 
+    // Add another bonus if the pawn push attacks an enemy piece
     b =  (shift_bb<Left>(b) | shift_bb<Right>(b))
        &  pos.pieces(Them)
        & ~ei.attackedBy[Us][PAWN];