Data commit

Task/Atomic-updates/Rust/atomic-updates.rust

@@ -0,0 +1,73 @@
+extern crate rand;
+
+use std::sync::{Arc, Mutex};
+use std::thread;
+use std::cmp;
+use std::time::Duration;
+
+use rand::Rng;
+use rand::distributions::{IndependentSample, Range};
+
+trait Buckets {
+    fn equalize<R:Rng>(&mut self, rng: &mut R);
+    fn randomize<R:Rng>(&mut self, rng: &mut R);
+    fn print_state(&self);
+}
+
+impl Buckets for [i32] {
+    fn equalize<R:Rng>(&mut self, rng: &mut R) {
+        let range = Range::new(0,self.len()-1);
+        let src = range.ind_sample(rng);
+        let dst = range.ind_sample(rng);
+        if dst != src {
+            let amount = cmp::min(((dst + src) / 2) as i32, self[src]);
+            let multiplier = if amount >= 0 { -1 } else { 1 };
+            self[src] += amount * multiplier;
+            self[dst] -= amount * multiplier;
+        }
+    }
+    fn randomize<R:Rng>(&mut self, rng: &mut R) {
+        let ind_range = Range::new(0,self.len()-1);
+        let src = ind_range.ind_sample(rng);
+        let dst = ind_range.ind_sample(rng);
+        if dst != src {
+            let amount = cmp::min(Range::new(0,20).ind_sample(rng), self[src]);
+            self[src] -= amount;
+            self[dst] += amount;
+
+        }
+    }
+    fn print_state(&self) {
+        println!("{:?} = {}", self, self.iter().sum::<i32>());
+    }
+}
+
+fn main() {
+    let e_buckets = Arc::new(Mutex::new([10; 10]));
+    let r_buckets = e_buckets.clone();
+    let p_buckets = e_buckets.clone();
+
+    thread::spawn(move || {
+        let mut rng = rand::thread_rng();
+        loop {
+            let mut buckets = e_buckets.lock().unwrap();
+            buckets.equalize(&mut rng);
+        }
+    });
+    thread::spawn(move || {
+        let mut rng = rand::thread_rng();
+        loop {
+            let mut buckets = r_buckets.lock().unwrap();
+            buckets.randomize(&mut rng);
+        }
+    });
+
+    let sleep_time = Duration::new(1,0);
+    loop {
+        {
+            let buckets = p_buckets.lock().unwrap();
+            buckets.print_state();
+        }
+        thread::sleep(sleep_time);
+    }
+}