From 828e40c452b76c2ff5150b19e65fd91f810925c0 Mon Sep 17 00:00:00 2001
From: Iaroslav Postovalov <postovalovya@gmail.com>
Date: Tue, 27 Oct 2020 19:19:53 +0700
Subject: [PATCH] Add toQuaternion extension for Complex

---
 .../kscience/kmath/operations/Quaternion.kt      | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Quaternion.kt b/kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Quaternion.kt
index 96331bd8a..a4574cb60 100644
--- a/kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Quaternion.kt
+++ b/kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Quaternion.kt
@@ -68,7 +68,7 @@ public object QuaternionField : Field<Quaternion>, Norm<Quaternion, Quaternion>,
         a.w * b.z + a.x * b.y - a.y * b.x + a.z * b.w,
     )
 
-    override fun divide(a: Quaternion, b: Quaternion): Quaternion {
+    public override fun divide(a: Quaternion, b: Quaternion): Quaternion {
         val s = b.w * b.w + b.x * b.x + b.y * b.y + b.z * b.z
 
         return Quaternion(
@@ -196,8 +196,7 @@ public object QuaternionField : Field<Quaternion>, Norm<Quaternion, Quaternion>,
  * @property z The fourth component.
  */
 public data class Quaternion(val w: Double, val x: Double, val y: Double, val z: Double) :
-    FieldElement<Quaternion, Quaternion, QuaternionField>,
-    Comparable<Quaternion> {
+    FieldElement<Quaternion, Quaternion, QuaternionField>, Comparable<Quaternion> {
     public constructor(w: Number, x: Number, y: Number, z: Number) : this(
         w.toDouble(),
         x.toDouble(),
@@ -240,10 +239,19 @@ public data class Quaternion(val w: Double, val x: Double, val y: Double, val z:
  * Creates a quaternion with real part equal to this real.
  *
  * @receiver the real part.
- * @return the new quaternion.
+ * @return a new quaternion.
  */
 public fun Number.toQuaternion(): Quaternion = Quaternion(this, 0, 0, 0)
 
+/**
+ * Creates a quaternion with `w`-component equal to `re`-component of given complex and `x`-component equal to
+ * `im`-component of given complex.
+ *
+ * @receiver the complex number.
+ * @return a new quaternion.
+ */
+public fun Complex.toQuaternion(): Quaternion = Quaternion(re, im, 0, 0)
+
 /**
  * Creates a new buffer of quaternions with the specified [size], where each element is calculated by calling the
  * specified [init] function.