Haversine distance and some changes

Change workload to float and coordinated to Double

src/main/scala/Main.scala

@@ -50,24 +50,23 @@ object Main {
         Array(0 , 42, 66, 31, 0)
     );
 
-    //format: on
+    // format: on
 
     // Prim's algorithm
 
     val selected: ArrayBuffer[Boolean] =
-      ArrayBuffer.from(Array.ofDim[Boolean](5).toIndexedSeq)
+      ArrayBuffer.fill(5)(false)
 
     selected(0) = true
 
-    var numberOfEdges = 0
 
-    for (_ <- numberOfEdges to 3) {
+    for (_ <- 0 until 4) {
       var min = 999999
       var x = 0
       var y = 0
-      for (i <- 0 to 4) {
+      for (i <- 0 until 5) {
         if (selected(i) == true) {
-          for (j <- 0 to 4) {
+          for (j <- 0 until 5) {
             if (selected(j) == false && edges(i)(j) != 0) {
               if (min > edges(i)(j)) {
                 min = edges(i)(j)
@@ -100,15 +99,19 @@ object Main {
       }
     }
 
-    println(edges2) // prints adjacency matrix
+    edges2.foreach { e =>
+      e.foreach { d =>
+        print(f"$d%.2f, ")
+      }
+      println()
+    }
 
-    // ArrayBuffer(
-    //   ArrayBuffer(0.0               , 1.4142135623730951, 1.0              , 5.0              , 2.0),
-    //   ArrayBuffer(1.4142135623730951, 0.0               , 1.0              , 5.0              , 3.1622776601683795),
-    //   ArrayBuffer(1.0               , 1.0               , 0.0              , 4.242640687119285, 2.23606797749979),
-    //   ArrayBuffer(5.0               , 5.0               , 4.242640687119285, 0.0              , 4.123105625617661),
-    //   ArrayBuffer(2.0               , 3.1622776601683795, 2.23606797749979 , 4.123105625617661, 0.0),
-    // )
+    // prints
+    // 0.00  , 159.64, 112.79, 563.55, 225.88
+    // 159.64, 0.00  , 112.94, 564.16, 357.08
+    // 112.79, 112.94, 0.00  , 478.40, 252.42
+    // 563.55, 564.16, 478.40, 0.00  , 463.64
+    // 225.88, 357.08, 252.42, 463.64, 0.00
 
   }
 }

src/main/scala/model/Coord.scala

@@ -1,5 +1,7 @@
 package model
 
-case class Coord(latitude: Long, longitude: Long) {
-  lazy val distance = math.sqrt(math.pow(latitude, 2) + math.pow(longitude, 2)) // distance is automatically calculated
+import util.Util
+
+case class Coord(latitude: Double, longitude: Double) {
+  lazy val distance = Util.getHaversineDistance(latitude, longitude) // distance is automatically calculated
 }

src/main/scala/model/Customer.scala

@@ -1,3 +1,3 @@
 package model
 
-case class Customer(location: Coord, workload: Int)
+case class Customer(location: Coord, workload: Float)

src/main/scala/model/HHCEdge.scala

@@ -1,10 +1,8 @@
 package model
 
 import scala.math.{sqrt, pow}
+import util.Util
 
 case class HHCEdge(v1: Customer, v2: Customer) {
-  val weight = sqrt( //automatically compute the distance between customers
-    pow(v1.location.latitude - v2.location.latitude, 2) +
-      pow(v1.location.longitude - v2.location.longitude, 2)
-  )
+  val weight = Util.getHaversineDistance(v1.location, v2.location)
 }

src/main/scala/util/Util.scala

@@ -0,0 +1,47 @@
+package util
+
+import model.Coord
+import scala.math._
+
+object Util {
+  private val r = 6471.00 // km
+
+  def toRad(num: Double): Double = {
+    val a = num * Pi / 180
+    a
+  }
+
+  def getHaversineDistance(c1: Coord, c2: Coord): Double = {
+    val x1 = c1.latitude - c2.latitude
+    val x2 = c1.longitude - c2.longitude
+
+    val dlat = toRad(x1)
+    val dlon = toRad(x2)
+
+    val a = pow(sin(dlat / 2), 2) +
+      cos(toRad(c1.latitude)) *
+        cos(toRad((c2.latitude))) *
+        pow(sin(dlon / 2), 2)
+
+    val c = 2 * atan2(sqrt(a), sqrt(1 - a))
+    val d = r * c
+    d
+  }
+
+  def getHaversineDistance(lat: Double, lon: Double): Double = {
+    val x1 = lat
+    val x2 = lon
+
+    val dlat = toRad(x1)
+    val dlon = toRad(x2)
+
+    val a = pow(sin(dlat / 2), 2) +
+      cos(toRad(x1)) *
+        cos(toRad((0))) *
+        pow(sin(dlon / 2), 2)
+
+    val c = 2 * atan2(sqrt(a), sqrt(1 - a))
+    val d = r * c
+    d
+  }
+}