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Improve efficiency of motley-batch-lexicase-selection

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Lee Spector 2023-09-03 10:06:42 -04:00
parent 06e9f9445d
commit 1facb741e6
1 changed files with 17 additions and 19 deletions
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34
src/propeller/selection.cljc
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@ -31,26 +31,24 @@
(defn motley-batch-lexicase-selection (defn motley-batch-lexicase-selection
"Selects an individual from the population using motley batch lexicase selection. "Selects an individual from the population using motley batch lexicase selection.
Cases are combined in random collections of max size (:max-batch-size argmap), Cases are combined in random collections of max size (:max-batch-size argmap)."
and then the population is passed to lexicase-selection."
[pop argmap] [pop argmap]
(let [cases (range (count (:errors (first pop)))) (loop [survivors (map rand-nth (vals (group-by :errors pop)))
batches (loop [remaining (shuffle cases) cases (shuffle (range (count (:errors (first pop)))))]
result ()] (if (or (empty? cases)
(if (empty? remaining) (empty? (rest survivors)))
result (rand-nth survivors)
(let [n (inc (rand-int (:max-batch-size argmap)))] (let [batch-size (inc (rand-int (:max-batch-size argmap)))
(recur (drop n remaining) batch (take batch-size cases)
(conj result (take n remaining))))))] ind-err-pairs (map (fn [ind]
(lexicase-selection (mapv (fn [ind] [ind
(assoc ind
:errors
(mapv (fn [batch]
(reduce + (map #(nth (:errors ind) %) (reduce + (map #(nth (:errors ind) %)
batch))) batch))])
batches))) survivors)
pop) min-err (apply min (map second ind-err-pairs))]
argmap))) (recur (map first (filter #(= (second %) min-err)
ind-err-pairs))
(drop batch-size cases))))))
(defn epsilon-list (defn epsilon-list
"List of epsilons for each training case based on median absolute deviation of errors." "List of epsilons for each training case based on median absolute deviation of errors."