Data commit

Task/Evolutionary-algorithm/EchoLisp/evolutionary-algorithm.l

@@ -0,0 +1,38 @@
+(require 'sequences)
+(define ALPHABET (list->vector  ["A" .. "Z"] ))
+(vector-push ALPHABET " ")
+
+(define (fitness source target) ;; score >=0, best is 0
+	(for/sum  [(s source)(t target)]
+		(if (= s t) 0 1)))
+		
+(define (mutate source rate)
+	(for/string [(s source)]
+		(if (< (random) rate) [ALPHABET (random 27)] s)))
+		
+(define (select parent target rate copies (copy) (score))
+	(define best (fitness parent target))
+	(define selected parent)
+	(for [(i copies)]
+		(set! copy (mutate parent rate))
+		(set! score (fitness copy target))
+		(when (< score  best)
+			(set! selected copy)
+			(set! best  score)))
+	selected )
+	
+(define MUTATION_RATE 0.05) ;; 5% chances to change
+(define COPIES 100)
+(define TARGET "METHINKS IT IS LIKE A WEASEL")
+
+(define (task (rate MUTATION_RATE) (copies COPIES) (target TARGET) (score))
+	(define parent ;; random source
+		(for/string
+                [(i (string-length target))] [ALPHABET (random 27)]))
+		
+	(for [(i (in-naturals))]
+		(set! score (fitness parent target))
+		(writeln i parent 'score score)
+		#:break (zero? score)
+		(set! parent (select parent target rate copies))
+		))