Adding random number test state

gemla/Cargo.toml

@@ -21,3 +21,4 @@ regex = "1"
 file_linked = { version = "0.1.0", path = "../file_linked" }
 thiserror = "1.0"
 anyhow = "1.0"
+rand = "0.8.4"

gemla/src/bin/bin.rs

@@ -2,6 +2,8 @@
 extern crate clap;
 extern crate gemla;
 
+mod test_state;
+
 use clap::App;
 use std::fs::metadata;
 

gemla/src/bin/test_state/mod.rs

@@ -0,0 +1,78 @@
+use rand::prelude::*;
+use rand::rngs::ThreadRng;
+use gemla::bracket::genetic_node::GeneticNode;
+use gemla::error;
+use std::convert::TryInto;
+
+const POPULATION_SIZE: u64 = 5;
+
+struct TestState {
+    pub population: Vec<f64>,
+    thread_rng: ThreadRng
+}
+
+impl GeneticNode for TestState {
+    fn initialize() -> Result<Box<Self>, error::Error> {
+        let mut thread_rng = rand::thread_rng();
+        let mut population: Vec<f64> = vec![];
+
+        for _ in 0..POPULATION_SIZE {
+            population.push(thread_rng.gen::<u64>() as f64)
+        }
+
+        Ok(Box::new(TestState {
+            population,
+            thread_rng
+        }))
+    }
+
+    fn simulate(&mut self, iterations: u64) -> Result<(), error::Error> {
+        for _ in 0..iterations {
+            self.population = self.population.clone().iter().map(|p| p + self.thread_rng.gen_range(-10.0..10.0)).collect()
+        }
+
+        Ok(())
+    }
+
+    fn get_fit_score(&self) -> f64 {
+        self.population.clone().into_iter().reduce(f64::max).unwrap()
+    }
+
+    fn calculate_scores_and_trim(&mut self) -> Result<(), error::Error> {
+        let mut v = self.population.clone();
+
+        v.sort_by(|a, b| a.partial_cmp(b).unwrap());
+
+        self.population = v[4..].to_vec();
+
+        Ok(())
+    }
+
+    fn mutate(&mut self) -> Result<(), error::Error> {
+        loop {
+            if self.population.len() >= POPULATION_SIZE.try_into().unwrap() {
+                break;
+            }
+
+            let new_individual_index = self.thread_rng.gen_range(0..self.population.len());
+            let mut cross_breed_index = self.thread_rng.gen_range(0..self.population.len());
+            
+            loop {
+                if new_individual_index != cross_breed_index {
+                    break;
+                }
+
+                cross_breed_index = self.thread_rng.gen_range(0..self.population.len());
+            }
+
+            let mut new_individual = self.population.clone()[new_individual_index];
+            let cross_breed = self.population.clone()[cross_breed_index];
+            
+            new_individual += cross_breed + self.thread_rng.gen_range(-10.0..10.0);
+
+            self.population.push(new_individual);
+        }
+
+        Ok(())
+    }
+}