From: Arjun Temurnikar <arjuntemurnikano@gmail.com>
Date: Sun, 20 Apr 2014 23:44:18 +0000 (-0700)
Subject: Remove rook passers eval completely
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=fe23f27086a7871f987bb7e706400d57870ee37b

Remove rook passers eval completely

Tested in no-regression mode.

Passed STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17727 W: 3248 L: 3122 D: 11357

And (a very long!) LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 106327 W: 16258 L: 16265 D: 73804

bench: 7396783
---

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index a2ed91f8..ea65ab38 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -638,21 +638,6 @@ namespace {
             }
         } // rr != 0
 
-        // Rook pawns are a special case: They are sometimes worse, and
-        // sometimes better than other passed pawns. It is difficult to find
-        // good rules for determining whether they are good or bad. For now,
-        // we try the following: Increase the value for rook pawns if the
-        // other side has no pieces apart from a knight, and decrease the
-        // value if the other side has a rook or queen.
-        if (file_of(s) == FILE_A || file_of(s) == FILE_H)
-        {
-            if (pos.non_pawn_material(Them) <= KnightValueMg)
-                ebonus += ebonus / 4;
-
-            else if (pos.pieces(Them, ROOK, QUEEN))
-                ebonus -= ebonus / 4;
-        }
-
         if (pos.count<PAWN>(Us) < pos.count<PAWN>(Them))
             ebonus += ebonus / 4;