From: Arjun Temurnikar <arjuntemurnikano@gmail.com>
Date: Sat, 19 Apr 2014 01:54:23 +0000 (-0700)
Subject: Remove penalty for knight when few enemy pawns
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=6579a65bbb7037c077bb5bc66161faa8762a76db

Remove penalty for knight when few enemy pawns

Tested in standard mode at STC and no-regression
mode at LTC:

STC
LLR: 2.97 (-2.94,2.94) [-1.50,4.50]
Total: 19503 W: 3502 L: 3349 D: 12652

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 67474 W: 9974 L: 9921 D: 47579

bench: 8331217
---

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 8eb03648..f7a59de6 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -166,7 +166,6 @@ namespace {
   const Score RookOpenFile     = make_score(43, 21);
   const Score RookSemiopenFile = make_score(19, 10);
   const Score BishopPawns      = make_score( 8, 12);
-  const Score KnightPawns      = make_score( 8,  4);
   const Score MinorBehindPawn  = make_score(16,  0);
   const Score UndefendedMinor  = make_score(25, 10);
   const Score TrappedRook      = make_score(90,  0);
@@ -349,10 +348,6 @@ namespace {
             if (Pt == BISHOP)
                 score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
 
-            // Penalty for knight when there are few enemy pawns
-            if (Pt == KNIGHT)
-                score -= KnightPawns * std::max(5 - pos.count<PAWN>(Them), 0);
-
             // Bishop and knight outposts squares
             if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
                 score += evaluate_outposts<Pt, Us>(pos, ei, s);