From 93f3c1e2ca701a9058cec9b5c3c102db4f2202e7 Mon Sep 17 00:00:00 2001
From: ProgramciDusunur <lerenarazl@gmail.com>
Date: Sat, 1 Feb 2025 21:42:25 +0300
Subject: [PATCH 1/2] add winnable heuristic

---
 src/evaluation.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/src/evaluation.c b/src/evaluation.c
index 6ab52f56..8c9b6a26 100644
--- a/src/evaluation.c
+++ b/src/evaluation.c
@@ -276,6 +276,9 @@ int evaluate(board* position) {
     // penalties
     //int double_pawns = 0;
 
+    // passer pawn count
+    int passedPawnCount = 0;
+
     // loop over piece bitboards
     for (int bb_piece = P; bb_piece <= k; bb_piece++) {
         // init piece bitboard copy
@@ -351,6 +354,7 @@ int evaluate(board* position) {
                     if ((whitePassedMasks[square] & position->bitboards[p]) == 0) {
                         // give passed pawn bonus
                         if (game_phase == endgame) {
+                            passedPawnCount += 1;
 
                             int whiteKingDistance = (getLS1BIndex(position->bitboards[K]) - square) / 8;
                             int blackKingDistance = (getLS1BIndex(position->bitboards[k]) - square) / 8;
@@ -508,6 +512,8 @@ int evaluate(board* position) {
                     if ((blackPassedMasks[square] & position->bitboards[P]) == 0) {
                         // give passed pawn bonus
                         if (game_phase == endgame) {
+                            passedPawnCount -= 1;
+
                             int whiteKingDistance = (getLS1BIndex(position->bitboards[K]) - square) / 8;
                             int blackKingDistance = (getLS1BIndex(position->bitboards[k]) - square) / 8;
                             int kingDistance = whiteKingDistance - blackKingDistance;
@@ -631,6 +637,21 @@ int evaluate(board* position) {
             popBit(bitboard, square);
         }
     }
+
+    int infiltriation = 0;
+    if (!position->side && get_rank[getLS1BIndex(position->bitboards[K])] > 5) {
+        infiltriation = 20;
+    } else if (position->side && get_rank[getLS1BIndex(position->bitboards[k])] < 2) {
+        infiltriation = -20;
+    }
+    // winnable
+    int winnableScore = 6 * passedPawnCount +
+                        8 * (countBits(position->bitboards[P]) - countBits(position->bitboards[p])) +
+                        infiltriation
+    ;
+    score += winnableScore;
+
+
     int tempo = 10;
     // return final evaluation based on side
     return (position->side == white) ? score + tempo : -(score - tempo);

From 7267114cc6272b083bc151a4e6d0de612d2b8cb9 Mon Sep 17 00:00:00 2001
From: ProgramciDusunur <lerenarazl@gmail.com>
Date: Sat, 1 Feb 2025 21:42:31 +0300
Subject: [PATCH 2/2] bench: 10738152

---
 src/evaluation.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/evaluation.c b/src/evaluation.c
index 8c9b6a26..d30944b1 100644
--- a/src/evaluation.c
+++ b/src/evaluation.c
@@ -651,7 +651,6 @@ int evaluate(board* position) {
     ;
     score += winnableScore;
 
-
     int tempo = 10;
     // return final evaluation based on side
     return (position->side == white) ? score + tempo : -(score - tempo);