particles

particles.clj

(ns nasser.particles)

(defn new-particle
  ([x y vx vy] {::x x ::y y ::vx vx ::vy vy})
  ([x y] (new-particle x y 0 0)))

(defn particles-at-origin [n]
 (repeat n (new-particle 0 0)))

(defn random-particle []
  (new-particle (rand) (rand) (rand) (rand)))

(defn particles-around-origin [n]
 (repeatedly n random-particle))

(defn particle-grid [n m distance]
  (for [x (range n)
        y (range m)]
    (new-particle (* x distance) (* y distance))))

(defn update-particles [sys dt]
  (map
    (fn [{:keys [::x ::y ::vx ::vy]}]
      (new-particle
        (+ x (* dt vx))
        (+ y (* dt vy))
        vx
        vy))
    sys))

(defn new-system [ps]
  (atom ps))

(defn update-all-particles! [sys dt]
  (swap! sys update-particles dt))

(defn all-steps [n]
  (->> (particles-around-origin n)
       (iterate #(update-particles % 1))))

(comment
  (-> test-particles ; (particles-around-origin 2)
      (update-particles 1)
      (update-particles 1)
      (update-particles 1)
      (update-particles 1)
      (update-particles 1)
      ; new-system
      ; (update-all-particles! 1)
      pprint
      ))