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

@@ -18,45 +18,5 @@ public data class Circle2D(
     public val radius: Double
 )
 
-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)
-    val d = line.begin.distanceTo(line.end)
-    val angle1 = atan2(other.center.x - this.center.x, other.center.y - this.center.y)
-    var r: Double
-    var angle2: Double
-    val routes = mapOf(
-        DubinsRoutes.RSR to Pair(R1, R2),
-        DubinsRoutes.RSL to Pair(R1, -R2),
-        DubinsRoutes.LSR to Pair(-R1, R2),
-        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
-        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 = Euclidean2DSpace.vector(-cos(angle2), sin(angle2))
-        segments[route] = LineSegment(
-            Euclidean2DSpace.add(this.center, Euclidean2DSpace.scale(W, r1)),
-            Euclidean2DSpace.add(other.center, Euclidean2DSpace.scale(W, r2))
-        )
-    }
-    return segments
-}
 
 public val Circle2D.circumference: Double get() = radius * 2 * PI

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

@@ -3,43 +3,43 @@
  * 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
+//package space.kscience.kmath.geometry
-
+//
-import space.kscience.kmath.geometry.Euclidean2DSpace.equalLineSegments
+//import space.kscience.kmath.geometry.Euclidean2DSpace.equalLineSegments
-import space.kscience.kmath.geometry.Euclidean2DSpace.vector
+//import space.kscience.kmath.geometry.Euclidean2DSpace.vector
-import kotlin.test.Test
+//import kotlin.test.Test
-import kotlin.test.assertEquals
+//import kotlin.test.assertEquals
-import kotlin.test.assertTrue
+//import kotlin.test.assertTrue
-
+//
-class TangentTest {
+//class TangentTest {
-    @Test
+//    @Test
-    fun tangent() {
+//    fun tangent() {
-        val c1 = Circle2D(vector(0.0, 0.0), 1.0)
+//        val c1 = Circle2D(vector(0.0, 0.0), 1.0)
-        val c2 = Circle2D(vector(4.0, 0.0), 1.0)
+//        val c2 = Circle2D(vector(4.0, 0.0), 1.0)
-        val routes = arrayListOf<DubinsRoutes>(
+//        val routes = arrayListOf<DubinsRoutes>(
-            DubinsRoutes.RSR,
+//            DubinsRoutes.RSR,
-            DubinsRoutes.RSL,
+//            DubinsRoutes.RSL,
-            DubinsRoutes.LSR,
+//            DubinsRoutes.LSR,
-            DubinsRoutes.LSL
+//            DubinsRoutes.LSL
-        )
+//        )
-        val segments = arrayListOf<LineSegment<DoubleVector2D>>(
+//        val segments = arrayListOf<LineSegment<DoubleVector2D>>(
-            LineSegment<DoubleVector2D>(begin = vector(0.0, 1.0),
+//            LineSegment<DoubleVector2D>(begin = vector(0.0, 1.0),
-                end = vector(4.0, 1.0)),
+//                end = vector(4.0, 1.0)),
-            LineSegment<DoubleVector2D>(begin = vector(0.5, 0.8660254),
+//            LineSegment<DoubleVector2D>(begin = vector(0.5, 0.8660254),
-                end = vector(3.5, -0.8660254)),
+//                end = vector(3.5, -0.8660254)),
-            LineSegment<DoubleVector2D>(begin = vector(0.5, -0.8660254),
+//            LineSegment<DoubleVector2D>(begin = vector(0.5, -0.8660254),
-                end = vector(3.5, 0.8660254)),
+//                end = vector(3.5, 0.8660254)),
-            LineSegment<DoubleVector2D>(begin = vector(0.0, -1.0),
+//            LineSegment<DoubleVector2D>(begin = vector(0.0, -1.0),
-                end = vector(4.0, -1.0))
+//                end = vector(4.0, -1.0))
-        )
+//        )
-
+//
-        val tangentMap = c1.tangentsToCircle(c2)
+//        val tangentMap = c1.tangentsToCircle(c2)
-        val tangentMapKeys = tangentMap.keys.toList()
+//        val tangentMapKeys = tangentMap.keys.toList()
-        val tangentMapValues = tangentMap.values.toList()
+//        val tangentMapValues = tangentMap.values.toList()
-
+//
-        assertEquals(routes, tangentMapKeys)
+//        assertEquals(routes, tangentMapKeys)
-        for (i in segments.indices) {
+//        for (i in segments.indices) {
-            assertTrue(equalLineSegments(segments[i], tangentMapValues[i]))
+//            assertTrue(equalLineSegments(segments[i], tangentMapValues[i]))
-        }
+//        }
-    }
+//    }
-}
+//}

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

@@ -0,0 +1,55 @@
+/*
+ * 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.trajectory
+
+import space.kscience.kmath.geometry.Circle2D
+import space.kscience.kmath.geometry.DoubleVector2D
+import space.kscience.kmath.geometry.Euclidean2DSpace
+import space.kscience.kmath.geometry.Euclidean2DSpace.distanceTo
+import space.kscience.kmath.geometry.LineSegment
+import kotlin.math.*
+
+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)
+    val d = line.begin.distanceTo(line.end)
+    val angle1 = atan2(other.center.x - this.center.x, other.center.y - this.center.y)
+    var r: Double
+    var angle2: Double
+    val routes = mapOf(
+        DubinsRoutes.RSR to Pair(R1, R2),
+        DubinsRoutes.RSL to Pair(R1, -R2),
+        DubinsRoutes.LSR to Pair(-R1, R2),
+        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
+        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 = Euclidean2DSpace.vector(-cos(angle2), sin(angle2))
+        segments[route] = LineSegment(
+            Euclidean2DSpace.add(this.center, Euclidean2DSpace.scale(W, r1)),
+            Euclidean2DSpace.add(other.center, Euclidean2DSpace.scale(W, r2))
+        )
+    }
+    return segments
+}

kmath-trajectory/src/commonTest/kotlin/space/kscience/kmath/trajectory/segments/TangentTest.kt

@@ -0,0 +1,48 @@
+/*
+ * 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.trajectory
+
+import space.kscience.kmath.geometry.Circle2D
+import space.kscience.kmath.geometry.DoubleVector2D
+import space.kscience.kmath.geometry.Euclidean2DSpace.equalLineSegments
+import space.kscience.kmath.geometry.Euclidean2DSpace.vector
+import space.kscience.kmath.geometry.LineSegment
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class TangentTest {
+    @Test
+    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<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)),
+            LineSegment<DoubleVector2D>(begin = vector(0.5, 0.8660254),
+                end = vector(3.5, -0.8660254)),
+            LineSegment<DoubleVector2D>(begin = vector(0.5, -0.8660254),
+                end = vector(3.5, 0.8660254)),
+            LineSegment<DoubleVector2D>(begin = vector(0.0, -1.0),
+                end = vector(4.0, -1.0))
+        )
+
+        val tangentMap = c1.tangentsToCircle(c2)
+        val tangentMapKeys = tangentMap.keys.toList()
+        val tangentMapValues = tangentMap.values.toList()
+
+        assertEquals(routes, tangentMapKeys)
+        for (i in segments.indices) {
+            assertTrue(equalLineSegments(segments[i], tangentMapValues[i]))
+        }
+    }
+}