kmath-geometry/src/commonMain/kotlin/space/kscience/kmath/geometry/Circle2D.kt

@@ -18,7 +18,11 @@ public data class Circle2D(
     public val radius: Double
 )
 
-public fun Circle2D.tangentsToCircle(other: Circle2D): kotlin.collections.MutableMap<String, LineSegment<DoubleVector2D>> {
+public enum class DubinsRoutes {
+    RSR, RSL, LSR, LSL
+}
+
+public fun Circle2D.tangentsToCircle(other: Circle2D): Map<DubinsRoutes, LineSegment<DoubleVector2D>> {
     val R1 = this.radius
     val R2 = other.radius
     val line = LineSegment(this.center, other.center)
@@ -26,11 +30,12 @@ public fun Circle2D.tangentsToCircle(other: Circle2D): kotlin.collections.Mutabl
     val angle1 = atan2(other.center.x - this.center.x, other.center.y - this.center.y)
     var r: Double
     var angle2: Double
-    val routes = mapOf("RSR" to Pair(R1, R2),
+    val routes = mapOf(
-        "RSL" to Pair(R1, -R2),
+        DubinsRoutes.RSR to Pair(R1, R2),
-        "LSR" to Pair(-R1, R2),
+        DubinsRoutes.RSL to Pair(R1, -R2),
-        "LSL" to Pair(-R1, -R2))
+        DubinsRoutes.LSR to Pair(-R1, R2),
-    val segments = mutableMapOf<String, LineSegment<DoubleVector2D>>()
+        DubinsRoutes.LSL to Pair(-R1, -R2))
+    val segments = mutableMapOf<DubinsRoutes, LineSegment<DoubleVector2D>>()
     for ((route, r1r2) in routes) {
         val r1 = r1r2.first
         val r2 = r1r2.second

kmath-geometry/src/commonMain/kotlin/space/kscience/kmath/geometry/Euclidean2DSpace.kt

@@ -85,6 +85,13 @@ public object Euclidean2DSpace : GeometrySpace<DoubleVector2D>,
     override fun scale(a: DoubleVector2D, value: Double): DoubleVector2D = vector(a.x * value, a.y * value)
     override fun DoubleVector2D.dot(other: DoubleVector2D): Double = x * other.x + y * other.y
 
+    public fun equalLineSegments(line1: LineSegment<DoubleVector2D>, line2: LineSegment<DoubleVector2D>): Boolean {
+        val maxFloatDelta = 0.000001
+        return line1.begin.x.equalFloat(line2.begin.x) && line1.begin.y.equalFloat(line2.begin.y) &&
+                line1.end.x.equalFloat(line2.end.x) && line1.end.y.equalFloat(line2.end.y)
+    }
+
+
     public val xAxis: DoubleVector2D = vector(1.0, 0.0)
     public val yAxis: DoubleVector2D = vector(0.0, 1.0)
 }

kmath-geometry/src/commonMain/kotlin/space/kscience/kmath/geometry/Line.kt

@@ -27,12 +27,6 @@ public fun <V : Vector> LineSegment<V>.line(algebra: GeometrySpace<V>): Line<V>
     Line(begin, end - begin)
 }
 
-public fun equalLineSegments(line1: LineSegment<DoubleVector2D>, line2: LineSegment<DoubleVector2D>): Boolean {
-    val maxFloatDelta = 0.000001
-    return line1.begin.x.equalFloat(line2.begin.x) && line1.begin.y.equalFloat(line2.begin.y) &&
-            line1.end.x.equalFloat(line2.end.x) && line1.end.y.equalFloat(line2.end.y)
-//    return line1.begin == line2.begin && line1.end == line2.end
-}
 
 public fun Double.equalFloat(other: Double, maxFloatDelta: Double = 0.000001):
         Boolean = kotlin.math.abs(this - other) < maxFloatDelta

kmath-geometry/src/commonMain/kotlin/space/kscience/kmath/geometry/Tangent.kt

@@ -1,75 +0,0 @@
-/*
- * Copyright 2018-2023 KMath contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package space.kscience.kmath.geometry
-
-import kotlin.math.absoluteValue
-import kotlin.math.atan2
-import kotlin.math.pow
-import kotlin.math.sign
-import kotlin.math.sin
-import kotlin.math.cos
-import space.kscience.kmath.geometry.Euclidean2DSpace.vector
-import space.kscience.kmath.geometry.Euclidean2DSpace.scale
-import space.kscience.kmath.geometry.Euclidean2DSpace.add
-import space.kscience.kmath.geometry.Euclidean2DSpace.distanceTo
-
-
-//public class Segment(
-//    public val startPoint: DoubleVector2D,
-//    public val terminalPoint: DoubleVector2D,
-//    public val length: Double = startPoint.distanceTo(terminalPoint)
-//) {
-//    public override operator fun equals(other: Any?): Boolean {
-//        return if (other is Segment) {
-//            startPoint.x.equalFloat(other.startPoint.x) && startPoint.y.equalFloat(other.startPoint.y) &&
-//                    terminalPoint.x.equalFloat(other.terminalPoint.x) && terminalPoint.y.equalFloat(other.terminalPoint.y)
-//        } else {
-//            false
-//        }
-//    }
-//}
-
-//public const val maxFloatDelta: Double = 0.000001
-//public fun Double.equalFloat(other: Double): Boolean = kotlin.math.abs(this - other) < maxFloatDelta
-
-
-
-//public fun tangentsToCircles(
-//    startCircle: Circle2D,
-//    terminalCircle: Circle2D
-//): kotlin.collections.MutableMap<String, LineSegment<DoubleVector2D>> {
-//    val R1 = startCircle.radius
-//    val R2 = terminalCircle.radius
-//    val line = LineSegment(startCircle.center, terminalCircle.center)
-//    val d = line.begin.distanceTo(line.end)
-//    val angle1 = atan2(terminalCircle.center.x - startCircle.center.x, terminalCircle.center.y - startCircle.center.y)
-//    var r: Double
-//    var angle2: Double
-//    val routes = mapOf("RSR" to Pair(R1, R2),
-//        "RSL" to Pair(R1, -R2),
-//        "LSR" to Pair(-R1, R2),
-//        "LSL" to Pair(-R1, -R2))
-//    val segments = mutableMapOf<String, LineSegment<DoubleVector2D>>()
-//    for ((route, r1r2) in routes) {
-//        val r1 = r1r2.first
-//        val r2 = r1r2.second
-//        r = if (r1.sign == r2.sign) {
-//            r1.absoluteValue - r2.absoluteValue
-//        } else {
-//            r1.absoluteValue + r2.absoluteValue
-//        }
-//        val L = (d * d - r * r).pow(0.5)
-//        angle2 = if (r1.absoluteValue > r2.absoluteValue) {
-//            angle1 + r1.sign * atan2(r.absoluteValue, L)
-//        } else {
-//            angle1 - r2.sign * atan2(r.absoluteValue, L)
-//        }
-//        val W = vector(-cos(angle2), sin(angle2))
-//        segments[route] = LineSegment(add(startCircle.center, scale(W, r1)),
-//            add(terminalCircle.center, scale(W, r2)))
-//    }
-//    return segments
-//}

kmath-geometry/src/commonTest/kotlin/space/kscience/kmath/geometry/TangentTest.kt

@@ -5,6 +5,7 @@
 
 package space.kscience.kmath.geometry
 
+import space.kscience.kmath.geometry.Euclidean2DSpace.equalLineSegments
 import space.kscience.kmath.geometry.Euclidean2DSpace.vector
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -15,7 +16,12 @@ class TangentTest {
     fun tangent() {
         val c1 = Circle2D(vector(0.0, 0.0), 1.0)
         val c2 = Circle2D(vector(4.0, 0.0), 1.0)
-        val routes = arrayListOf<String>("RSR", "RSL", "LSR", "LSL")
+        val routes = arrayListOf<DubinsRoutes>(
+            DubinsRoutes.RSR,
+            DubinsRoutes.RSL,
+            DubinsRoutes.LSR,
+            DubinsRoutes.LSL
+        )
         val segments = arrayListOf<LineSegment<DoubleVector2D>>(
             LineSegment<DoubleVector2D>(begin = vector(0.0, 1.0),
                 end = vector(4.0, 1.0)),