Initial data commit

Task/Evolutionary-algorithm/Factor/evolutionary-algorithm.factor

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+USING: arrays formatting io kernel literals math prettyprint
+random sequences strings ;
+FROM: math.extras => ... ;
+IN: rosetta-code.evolutionary-algorithm
+
+CONSTANT: target "METHINKS IT IS LIKE A WEASEL"
+CONSTANT: mutation-rate 0.1
+CONSTANT: num-children 25
+CONSTANT: valid-chars
+    $[ CHAR: A ... CHAR: Z >array { 32 } append ]
+
+: rand-char ( -- n )
+    valid-chars random ;
+
+: new-parent ( -- str )
+    target length [ rand-char ] replicate >string ;
+
+: fitness ( str -- n )
+    target [ = ] { } 2map-as sift length ;
+
+: mutate ( str rate -- str/str' )
+    [ random-unit > [ drop rand-char ] when ] curry map ;
+
+: next-parent ( str -- str/str' )
+    dup [ mutation-rate mutate ] curry num-children 1 - swap
+    replicate [ 1array ] dip append [ fitness ] supremum-by ;
+
+: print-parent ( str -- )
+    [ fitness pprint bl ] [ print ] bi ;
+
+: main ( -- )
+    0 new-parent
+    [ dup target = ]
+    [ next-parent dup print-parent [ 1 + ] dip ] until drop
+    "Finished in %d generations." printf ;
+
+MAIN: main