Parametric version

georust · Aug 21, 2016 · e26beeb · e26beeb
1 parent 0be988f
commit e26beeb
Showing 2 changed files with 50 additions and 61 deletions.
diff --git a/src/algorithm/distance.rs b/src/algorithm/distance.rs
@@ -1,26 +1,17 @@
-use num::Float;
+use num::{Float, FromPrimitive};
 use types::{Point};
 
 /// Returns the distance between two geometries.
+trait Distance<T, Rhs = Self> {
+    fn distance<A: DistanceAlgorithm>(&self, rhs: &Rhs) -> T;
+}
 
-pub trait Distance<T, Rhs = Self>
-{
-    /// Returns the distance between two points:
-    ///
-    /// ```
-    /// use geo::{COORD_PRECISION, Point};
-    /// use geo::algorithm::distance::Distance;
-    ///
-    /// let p = Point::new(-72.1235, 42.3521);
-    /// let dist = p.distance(&Point::new(-72.1260, 42.45));
-    /// assert!(dist < COORD_PRECISION)
-    /// ```
-    fn distance(&self, rhs: &Rhs) -> T;
+trait EuclideanAlgorithm {
 }
 
-impl<T> Distance<T, Point<T>> for Point<T>
-    where T: Float
-{
+struct Euclidean;
+
+impl DistanceAlgorithm for Euclidean {
     fn distance(&self, p: &Point<T>) -> T {
         let (dx, dy) = (self.x() - p.x(), self.y() - p.y());
         dx.hypot(dy)
@@ -42,3 +33,45 @@ mod test {
         assert!(dist < 147. && dist > 146.);
     }
 }
+
+
+/// Returns the distance between two geometries.
+
+// pub trait HaversineDistance<T, Rhs = Self>
+// {
+//     /// Returns the distance between two points:
+//     ///
+//     /// ```
+//     /// use geo::{COORD_PRECISION, Point};
+//     /// use geo::algorithm::haversine_distance::HaversineDistance;
+//     ///
+//     /// let p = Point::new(-72.1235, 42.3521);
+//     /// let dist = p.haversine_distance(&Point::new(-72.1260, 42.45));
+//     /// assert_eq!(dist as i32, 10900)
+//     /// ```
+//     fn haversine_distance(&self, rhs: &Rhs) -> T;
+// }
+// 
+// impl<T> HaversineDistance<T, Point<T>> for Point<T>
+//     where T: Float + FromPrimitive
+// {
+//     // currently gives answer in meters
+//     fn haversine_distance(&self, p: &Point<T>) -> T {
+//         let a = (self.y().to_radians().sin() * p.y().to_radians().sin()) +
+//             (self.y().to_radians().cos() * p.y().to_radians().cos()) *
+//             (p.x() - self.x()).to_radians().cos();
+//         T::from_i32(6378137).unwrap() * a.acos().min(T::one())
+//     }
+// }
+// 
+// #[cfg(test)]
+// mod test {
+//     use types::Point;
+//     use algorithm::haversine_distance::HaversineDistance;
+//     #[test]
+//     fn distance3_test() {
+//         let dist = Point::new(-101.60, 37.43)
+//             .haversine_distance(&Point::new(-78.75, 40.97));
+//         assert_eq!(dist, 2004106.44144124);
+//     }
+// }
diff --git a/src/algorithm/haversine_distance.rs b/src/algorithm/haversine_distance.rs