tangentsToCircle fixed

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

@@ -6,7 +6,8 @@
 package space.kscience.kmath.geometry
 
 import kotlinx.serialization.Serializable
-import kotlin.math.PI
+import space.kscience.kmath.geometry.Euclidean2DSpace.distanceTo
+import kotlin.math.*
 
 /**
  * A circle in 2D space
@@ -17,4 +18,40 @@ public data class Circle2D(
     public val radius: Double
 )
 
+public fun Circle2D.tangentsToCircle(other: Circle2D): kotlin.collections.MutableMap<String, 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("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 = 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/commonMain/kotlin/space/kscience/kmath/geometry/Line.kt

@@ -27,5 +27,15 @@ 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
+
 public typealias LineSegment2D = LineSegment<DoubleVector2D>
 public typealias LineSegment3D = LineSegment<DoubleVector3D>

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

@@ -5,9 +5,6 @@
 
 package space.kscience.kmath.geometry
 
-import space.kscience.kmath.geometry.Euclidean2DSpace.distanceTo
-import space.kscience.kmath.linear.DoubleLinearSpace.plus
-import space.kscience.kmath.linear.Point
 import kotlin.math.absoluteValue
 import kotlin.math.atan2
 import kotlin.math.pow
@@ -15,63 +12,64 @@ 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.dot
 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 class Segment(
-    public val startPoint: DoubleVector2D,
+//    public val startPoint: DoubleVector2D,
-    public val terminalPoint: DoubleVector2D,
+//    public val terminalPoint: DoubleVector2D,
-    public val length: Double = startPoint.distanceTo(terminalPoint)
+//    public val length: Double = startPoint.distanceTo(terminalPoint)
-) {
+//) {
-    public override operator fun equals(other: Any?): Boolean {
+//    public override operator fun equals(other: Any?): Boolean {
-        return if (other is Segment) {
+//        return if (other is Segment) {
-            startPoint.x.equalFloat(other.startPoint.x) && startPoint.y.equalFloat(other.startPoint.y) &&
+//            startPoint.x.equalFloat(other.startPoint.x) && startPoint.y.equalFloat(other.startPoint.y) &&
-                    terminalPoint.x.equalFloat(other.terminalPoint.x) && terminalPoint.y.equalFloat(other.terminalPoint.y)
+//                    terminalPoint.x.equalFloat(other.terminalPoint.x) && terminalPoint.y.equalFloat(other.terminalPoint.y)
-        } else {
+//        } else {
-            false
+//            false
-        }
+//        }
-    }
+//    }
-}
+//}
 
-public const val maxFloatDelta: Double = 0.000001
+//public const val maxFloatDelta: Double = 0.000001
-public fun Double.equalFloat(other: Double): Boolean = kotlin.math.abs(this - other) < maxFloatDelta
+//public fun Double.equalFloat(other: Double): Boolean = kotlin.math.abs(this - other) < maxFloatDelta
 
 
 
-public fun tangentsToCircles(
+//public fun tangentsToCircles(
-    startCircle: Circle2D,
+//    startCircle: Circle2D,
-    terminalCircle: Circle2D
+//    terminalCircle: Circle2D
-): kotlin.collections.MutableMap<String, Segment> {
+//): kotlin.collections.MutableMap<String, LineSegment<DoubleVector2D>> {
-    val R1 = startCircle.radius
+//    val R1 = startCircle.radius
-    val R2 = terminalCircle.radius
+//    val R2 = terminalCircle.radius
-    val d = Segment(startCircle.center, terminalCircle.center).length
+//    val line = LineSegment(startCircle.center, terminalCircle.center)
-    val angle1 = atan2(terminalCircle.center.x - startCircle.center.x, terminalCircle.center.y - startCircle.center.y)
+//    val d = line.begin.distanceTo(line.end)
-    var r: Double
+//    val angle1 = atan2(terminalCircle.center.x - startCircle.center.x, terminalCircle.center.y - startCircle.center.y)
-    var angle2: Double
+//    var r: Double
-    val routes = mapOf("RSR" to Pair(R1, R2),
+//    var angle2: Double
-        "RSL" to Pair(R1, -R2),
+//    val routes = mapOf("RSR" to Pair(R1, R2),
-        "LSR" to Pair(-R1, R2),
+//        "RSL" to Pair(R1, -R2),
-        "LSL" to Pair(-R1, -R2))
+//        "LSR" to Pair(-R1, R2),
-    val segments = mutableMapOf<String, Segment>()
+//        "LSL" to Pair(-R1, -R2))
-    for ((route, r1r2) in routes) {
+//    val segments = mutableMapOf<String, LineSegment<DoubleVector2D>>()
-        val r1 = r1r2.first
+//    for ((route, r1r2) in routes) {
-        val r2 = r1r2.second
+//        val r1 = r1r2.first
-        r = if (r1.sign == r2.sign) {
+//        val r2 = r1r2.second
-            r1.absoluteValue - r2.absoluteValue
+//        r = if (r1.sign == r2.sign) {
-        } else {
+//            r1.absoluteValue - r2.absoluteValue
-            r1.absoluteValue + r2.absoluteValue
+//        } else {
-        }
+//            r1.absoluteValue + r2.absoluteValue
-        val L = (d * d - r * r).pow(0.5)
+//        }
-        angle2 = if (r1.absoluteValue > r2.absoluteValue) {
+//        val L = (d * d - r * r).pow(0.5)
-            angle1 + r1.sign * atan2(r.absoluteValue, L)
+//        angle2 = if (r1.absoluteValue > r2.absoluteValue) {
-        } else {
+//            angle1 + r1.sign * atan2(r.absoluteValue, L)
-            angle1 - r2.sign * atan2(r.absoluteValue, L)
+//        } else {
-        }
+//            angle1 - r2.sign * atan2(r.absoluteValue, L)
-        val W = vector(-cos(angle2), sin(angle2))
+//        }
-        segments[route] = Segment(add(startCircle.center, scale(W, r1)),
+//        val W = vector(-cos(angle2), sin(angle2))
-            add(terminalCircle.center, scale(W, r2)))
+//        segments[route] = LineSegment(add(startCircle.center, scale(W, r1)),
-    }
+//            add(terminalCircle.center, scale(W, r2)))
-    return segments
+//    }
-}
+//    return segments
+//}

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

@@ -8,6 +8,7 @@ package space.kscience.kmath.geometry
 import space.kscience.kmath.geometry.Euclidean2DSpace.vector
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertTrue
 
 class TangentTest {
     @Test
@@ -15,25 +16,24 @@ class TangentTest {
         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 segments = arrayListOf<Segment>(
+        val segments = arrayListOf<LineSegment<DoubleVector2D>>(
-            Segment(startPoint = vector(0.0, 1.0),
+            LineSegment<DoubleVector2D>(begin = vector(0.0, 1.0),
-                terminalPoint = vector(4.0, 1.0)),
+                end = vector(4.0, 1.0)),
-            Segment(startPoint = vector(0.5, 0.8660254),
+            LineSegment<DoubleVector2D>(begin = vector(0.5, 0.8660254),
-                terminalPoint = vector(3.5, -0.8660254)),
+                end = vector(3.5, -0.8660254)),
-            Segment(startPoint = vector(0.5, -0.8660254),
+            LineSegment<DoubleVector2D>(begin = vector(0.5, -0.8660254),
-                terminalPoint = vector(3.5, 0.8660254)),
+                end = vector(3.5, 0.8660254)),
-            Segment(startPoint = vector(0.0, -1.0),
+            LineSegment<DoubleVector2D>(begin = vector(0.0, -1.0),
-                terminalPoint = vector(4.0, -1.0))
+                end = vector(4.0, -1.0))
         )
 
-        val tangentMap = tangentsToCircles(c1, c2)
+        val tangentMap = c1.tangentsToCircle(c2)
         val tangentMapKeys = tangentMap.keys.toList()
         val tangentMapValues = tangentMap.values.toList()
 
         assertEquals(routes, tangentMapKeys)
         for (i in segments.indices) {
-            assertEquals(segments[i], tangentMapValues[i])
+            assertTrue(equalLineSegments(segments[i], tangentMapValues[i]))
         }
-//        assertEquals(segments, tangentMapValues)
     }
 }

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

@@ -44,3 +44,6 @@ fun <V : Vector> GeometrySpace<V>.isCollinear(a: V, b: V, absoluteTolerance: Dou
 
 fun <V : Vector> GeometrySpace<V>.isOrthogonal(a: V, b: V, absoluteTolerance: Double = 1e-6): Boolean =
     abs(a dot b) < absoluteTolerance
+
+fun Double.equalFloat(other: Double, maxFloatDelta: Double = 0.000001):
+        Boolean = kotlin.math.abs(this - other) < maxFloatDelta