proper chunks

src/main.rs

@@ -4,6 +4,8 @@ use rand::Rng;
 use std::fs::File;
 use std::io::prelude::*;
 
+mod utils;
+
 struct Node {
     x: f32,
     y: f32,
@@ -79,16 +81,16 @@ fn main() -> std::io::Result<()> {
     let nodes = nodes_list(size);
     let nodes_next = nodes_list(size);
 
+    let chunks = utils::chunk_borders(size, THREADS);
     for epoch in 0..ITER {
         let mut handles = vec![];
-        let chunks = size / THREADS;
         for i in 0..THREADS {
             let nodes = nodes.clone();
             let nodes_next = nodes_next.clone();
             let edges = edges.clone();
+            let chunk = chunks[i].clone();
             let handle = thread::spawn(move || {
-                for j in 0..chunks {
-                    let n = i * chunks + j;
+                for n in chunk {
                     let node = nodes[n].read().unwrap();
                     let edges = edges.read().unwrap();
     

src/utils.rs

@@ -0,0 +1,40 @@
+use std::ops::Range;
+
+pub fn chunk_borders(n: usize, chunks: usize) -> Vec<Range<usize>> {
+    let mut borders = vec![];
+    let chunk_size = n / chunks;
+    let mut start = 0;
+    for _ in 0..chunks {
+        let end = start + chunk_size;
+        borders.push(start..end);
+        start = end;
+    }
+    // Change the last chunk to include the remainder
+    let size = borders.len();
+    borders[size - 1].end = n;
+    borders
+}
+
+
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_chunk_borders() {
+        let borders = chunk_borders(10, 3);
+        assert_eq!(borders, vec![(0..3), (3..6), (6..10)]);
+    }
+
+    #[test]
+    fn test_chunk_borders2() {
+        let borders = chunk_borders(10, 2);
+        assert_eq!(borders, vec![(0..5), (5..10)]);
+    }
+
+    #[test]
+    fn test_chunk_borders3() {
+        let borders = chunk_borders(10, 1);
+        assert_eq!(borders, vec![(0..10)]);
+    }
+
+}