tournament-select.clj

(def num-participants 4) ;; how many solutions should take part in each tournament

(defn tournament-select [population]
  "order the members of the population according
   to their success in...battles to the death!"
  (mapv (fn [x] (let [idxs (repeatedly num-participants #(rand-int (count population)))
                      participants (map #(population %) idxs)]
                 (first (sort-by calculate-fitness participants))))
       (range (count population))))