use DIR_POS length for direction generation

src/lib.rs

@@ -349,10 +349,8 @@ impl Agent {
     const INACTIVE_PENALTY: f32 = 0.0010;
     const BOX_DIFF: f32 = 1024.0;
 
-    const DIR_TABLE: &'static [u32] = &[0, 1, 2, 3];
-
     fn chromo() -> u32 {
-        Self::DIR_TABLE[rnd!(Self::DIR_TABLE.len())]
+        rnd!(State::DIR_POS.len()) as u32
     }
 
     fn with_dna(state: State, dna: Vec<u32>) -> Self {