multithread the creation of the index

src/lib.rs

@@ -65,22 +65,32 @@ pub struct Spindex2d {
 impl Spindex2d {
     pub fn new(points: &[Point2d]) -> Self {
         let mut xpoints = Vec::with_capacity(points.len());
-        let mut ypoints = Vec::with_capacity(points.len());
         let mut xs = Vec::with_capacity(points.len());
+
+        let mut ypoints = Vec::with_capacity(points.len());
         let mut ys = Vec::with_capacity(points.len());
+
+        thread::scope(|s| {
+            s.spawn(|| {
                 for (i, point) in points.iter().enumerate() {
                     let x = PVal::new(i, point.x);
                     xs.push(x);
+                    xpoints.push(i);
+                }
+            });
+
+            s.spawn(|| {
+                for (i, point) in points.iter().enumerate() {
                     let y = PVal::new(i, point.y);
                     ys.push(y);
-
-            xpoints.push(i);
                     ypoints.push(i);
                 }
+            });
+        });
 
         let index = Self {
-            xpoints: Arc::new(xpoints.into()),
-            ypoints: Arc::new(ypoints.into()),
+            xpoints: Arc::new(RwLock::new(xpoints)),
+            ypoints: Arc::new(RwLock::new(ypoints)),
             xs: Arc::new(RwLock::new(xs)),
             ys: Arc::new(RwLock::new(ys)),
         };