add constants for agent rewards and penalties

src/lib.rs

@@ -343,6 +343,13 @@ struct Agent {
 }
 
 impl Agent {
+    const WIN_REWARD: f32 = 100000.0;
+    const BOX_REWARD: f32 = 0.00021;
+    const COL_PENALTY: f32 = 0.00080;
+    const LOSS_PENALTY: f32 = 0.0032;
+    const INACTIVE_PENALTY: f32 = 0.0010;
+    const BOX_DIFF: f32 = 1024.0;
+
     const DIR_TABLE: &'static [Direction] =
         &[Direction::U, Direction::D, Direction::L, Direction::R];
 
@@ -390,11 +397,11 @@ impl Agent {
             let (mb, hit) = self.state.move_dir(self.dna[self.dir])?;
 
             if mb {
-                self.score += 0.00021;
+                self.score += Self::BOX_REWARD;
             }
 
             if hit {
-                self.score -= 0.00080;
+                self.score -= Self::COL_PENALTY;
             }
 
             self.dir += 1;
@@ -409,23 +416,23 @@ impl Agent {
             match self.move_dna()? {
                 Solution::Ok => (),
                 Solution::Win => {
-                    self.score += 100000.0;
+                    self.score += Self::WIN_REWARD;
                     self.goal = Solution::Win;
                     break;
                 }
                 Solution::None => {
-                    self.score -= 0.0032;
+                    self.score -= Self::LOSS_PENALTY;
                     self.goal = Solution::None;
                     break;
                 }
             }
 
             if player == self.state.lvl.player {
-                self.score -= 0.0010;
+                self.score -= Self::INACTIVE_PENALTY;
             }
         }
 
-        self.score -= 1024.0 + self.state.dist_boxes() as f32;
+        self.score -= Self::BOX_DIFF + self.state.dist_boxes() as f32;
         Ok(())
     }