Connected / blocked pawns simplification

There is no need to score blocked pawns at many places.
The idea originated from: Rocky
Tuning and testing by: Fauzi

Passed STC:
https://tests.stockfishchess.org/tests/view/5f04f8fd59f6f035328945d4
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 6352 W: 1299 L: 1118 D: 3935
Ptnml(0-2): 89, 695, 1469, 792, 131

Passed LTC:
https://tests.stockfishchess.org/tests/view/5f0527bd59f6f035328945e3
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27648 W: 3517 L: 3433 D: 20698
Ptnml(0-2): 177, 2561, 8301, 2571, 214

closes https://github.com/official-stockfish/Stockfish/pull/2799

Bench: 4734746

diff --git a/src/pawns.cpp b/src/pawns.cpp
index f18e03155042112dc71e89472b55120ad26c312b..7f8d451a6d47202ba0be9a814d0656ea90282bb4 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -39,7 +39,7 @@ namespace {
   constexpr Score WeakUnopposed = S(13, 27);
 
   // Bonus for blocked pawns at 5th or 6th rank
-  constexpr Score BlockedPawn[2] = { S(-10, -3), S(-3, 3) };
+  constexpr Score BlockedPawn[2] = { S(-11, -4), S(-3, 4) };
 
   constexpr Score BlockedStorm[RANK_NB] = {
     S(0, 0), S(0, 0), S(76, 78), S(-10, 15), S(-7, 10), S(-4, 6), S(-1, 2)
@@ -148,7 +148,7 @@ namespace {
         // Score this pawn
         if (support | phalanx)
         {
-            int v =  Connected[r] * (4 + 2 * bool(phalanx) - 2 * bool(opposed) - bool(blocked)) / 2
+            int v =  Connected[r] * (2 + bool(phalanx) - bool(opposed))
                    + 21 * popcount(support);
 
             score += make_score(v, v * (r - 2) / 4);