Output max, mean, median, and minimum fitness values

src/population.rs

@@ -150,10 +150,25 @@ impl Population {
         let total = self.worlds.iter().fold(0., |acc, x| acc + x.fitness);
         self.worlds
             .sort_by(|a, b| b.fitness.partial_cmp(&a.fitness).unwrap());
-        for i in &self.worlds {
-            println!("Fitness: {}", i.fitness);
+        let mut scores: std::collections::VecDeque<_> =
+            self.worlds.iter().map(|w| w.fitness as f32).collect();
+        let mean: f32 = scores.iter().sum::<f32>() / scores.len() as f32;
+        while scores.len() > 2 {
+            scores.pop_front();
+            scores.pop_back();
         }
-        println!("Gen: {}, Fitness: {}", self.gen, self.worlds[0].fitness);
+        if scores.len() == 2 {
+            scores.pop_front();
+        }
+        let median = scores[0];
+
+        println!(
+            "{} {} {} {}",
+            self.worlds[0].fitness,
+            mean,
+            median,
+            self.worlds[self.worlds.len() - 1].fitness
+        );
         let mut new_worlds = (0..std::cmp::max(1, self.size / 20))
             .map(|i| World::simulate(self.worlds[i].see_brain().to_owned()))
             .collect::<Vec<_>>();