1 files changed, 12 insertions, 32 deletions
diff --git a/src/grossmeister/evaluation.rs b/src/grossmeister/evaluation.rs
index b78c49a..6fc4149 100644
--- a/src/grossmeister/evaluation.rs
+++ b/src/grossmeister/evaluation.rs
@@ -1,3 +1,5 @@
+use std::f32::INFINITY;
+
 use crate::{board::{piece::Piece, color::Color, CastlingSide}, bitboard::{Bitboard, BitboardFns}, square::Square};
 
 use super::Grossmeister;
@@ -117,34 +119,6 @@ impl Grossmeister {
         }
     }
 
-    pub fn is_dead_position(&self) -> bool {
-        let non_minor_exists = [
-            Piece::Pawn,
-            Piece::PawnBlack,
-            Piece::Rook,
-            Piece::RookBlack,
-            Piece::Queen,
-            Piece::QueenBlack
-        ].iter().any(|&piece| {
-            self.board.piece_sets[piece as usize].pop_count() > 0
-        });
-
-        if non_minor_exists {
-            return false;
-        }
-
-        let minor_pieces = [
-            Piece::Knight,
-            Piece::KnightBlack,
-            Piece::Bishop,
-            Piece::BishopBlack
-        ].iter().fold(0, |acc, &piece| {
-            acc + self.board.piece_sets[piece as usize].pop_count()
-        });
-
-        minor_pieces <= 1
-    }
-
     /// Return number of pawns above the king (+left/right)
     pub fn pawn_shield(&self, color: Color) -> f32 {
         let behind_pawns = match color {
@@ -236,12 +210,16 @@ impl Grossmeister {
 
     /// Evaluate a position relative to the current player
     pub fn evaluate(&self) -> f32 {
-        if self.is_dead_position() {
-            return 0.0
-        }
         let color = self.board.color();
         let opponent_color = color.flip();
 
+        let winnable = self.board.is_theoretically_winnable(color);
+        let loseable = self.board.is_theoretically_winnable(opponent_color);
+
+        if !winnable && !loseable {
+            return 0.0
+        }
+
         let material_advantage = self.material(color) - self.material(opponent_color);
         let mobility_advantage = self.mobility(color) - self.mobility(opponent_color);
         let pawn_shield_advantage = self.pawn_shield(color) - self.pawn_shield(opponent_color);
@@ -265,7 +243,9 @@ impl Grossmeister {
         let phase = self.phase();
         let tapered_eval = (middlegame_eval * phase as f32 + endgame_eval * (240 - phase) as f32) / 240.;
 
-        material_advantage + tapered_eval
+        (material_advantage + tapered_eval)
+            .min(if winnable { INFINITY } else { 0.0 }) // Can not score > 0 if not winnable
+            .max(if loseable { -INFINITY } else { 0.0 }) // Can not score < 0 if not loseable
     }
 
     /// Count pseudo-legal moves without actually generating them