salesman

gistfile1.clj

(ns salesman.core
  "finds the quickest path through cities"
  (:require [clojure.core.logic :as l]
            [clojure.contrib.math :as m]))

(def sample-city {:x 0 :y 0})
(def other-city  {:x 0 :y 0})

(defn random-city []
  {:x (int (rand 10)) :y (int (rand 10))})

(defn random-world [num-cities]
  (take num-cities (repeatedly random-city)))

(defn distance [city-one city-two]
  (let [square (fn [x] (* x x))]
    (m/sqrt (+ (square (- (:x city-one) (:x city-two))) (square (- (:y city-one) (:y city-two)))))))

(def little-world (random-world 3))


(defn move-to-front [first others]
  "Moves an item to the front of the list"
  (cons first (remove #(identical? first %) others)))
(defn first-iteration [list]
  "Returns a list of all first-level permutations."
  (map #(recursive-thingy % list) list))
(defn second-iteration [list] (cons (first list) (first-iteration (next list))))

;; salesman.core> (first-iteration [1 2 3 4 5])
;; ((1 2 3 4 5) (2 1 3 4 5) (3 1 2 4 5) (4 1 2 3 5) (5 1 2 3 4))
;; salesman.core> (map second-iteration (first-iteration [1 2 3 4 5]))
;; ((1 (2 3 4 5) (3 2 4 5) (4 2 3 5) (5 2 3 4)) (2 (1 3 4 5) (3 1 4 5) (4 1 3 5) (5 1 3 4)) (3 (1 2 4 5) (2 1 4 5) (4 1 2 5) (5 1 2 4)) (4 (1 2 3 5) (2 1 3 5) (3 1 2 5) (5 1 2 3)) (5 (1 2 3 4) (2 1 3 4) (3 1 2 4) (4 1 2 3)))