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cshepp/roulette-select.clj

Created March 22, 2015 22:15
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roulette-select.clj
(def fitness-multiplier 100)
(defn roulette-select [population]
"randomly selects solutions -
probability of being selected is
weighted using fitness score"
(let [roulette-wheel (reduce #(conj %1 (+ (* (- 700 %2) fitness-multiplier) (last %1))) [0] (map calculate-fitness population))
total (last roulette-wheel)]
(mapv (fn [x] (nth population (.indexOf roulette-wheel (first (filter #(< (rand-int total) %1) roulette-wheel)))))
(range (count population)))))
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