vec2.clj

(ns vector-math.core
  (:import [javax.vecmath Vector2d]))

(defprotocol Vec2Math
  (add [this other]))

(deftype vec2
  [#^float x #^float y] :as this
  Vec2Math 
  (add [other] (vec2. (+ x (.x #^vec2 other))
                      (+ y (.y #^vec2 other)))))

(def v1 (vec2 5.0 4.0))

;; ========== Create

;; ~50ms
(time
 (dotimes [x 1000000]
   [1.0 1.0]))

;; ~25ms
(time
 (dotimes [x 1000000]
   (vec2 1.0 1.0)))

;; ~18ms
(time
 (dotimes [x 1000000]
   (Vector2d. 1.0 1.0)))

;; ========== Access

;; ~28ms
(time
 (let [v [1.0 1.0]]
   (dotimes [x 1000000]
     (do
       (nth v 0)
       (nth v 1)))))

;; ~30ms
(time
 (let [v (vec2 1.0 1.0)]
   (dotimes [x 1000000]
     (do
       (:x v)
       (:y v)))))

;; ~27ms
(time
 (let [v (Vector2d. 1.0 1.0)]
   (dotimes [x 1000000]
     (do
       (.x v)
       (.y v)))))

;; ========== Add

;; ~70ms
(time
 (let [v1 [1.0 1.0]
       v2 [0.5 0.5]]
   (dotimes [x 1000000]
     (map + v1 v2))))

;; ~27ms
(time
 (let [v1 (vec2 1.0 1.0)
       v2 (vec2 0.5 0.5)]
   (dotimes [x 1000000]
     (add v1 v2))))

;; ~7ms (mutable)
(time
 (let [v1 (Vector2d. 1.0 1.0)
       v2 (Vector2d. 0.5 0.5)]
     (dotimes [x 1000000]
       (.add v1 v2))))

;; ~21ms (immutable)
(time
 (let [v1 (Vector2d. 1.0 1.0)
       v2 (Vector2d. 0.5 0.5)]
     (dotimes [x 1000000]
       (Vector2d. (+ (.x v1) (.x v2))
                  (+ (.y v1) (.y v2))))))