A-M baby

Task/Evolutionary-algorithm/J/evolutionary-algorithm-1.j

@@ -0,0 +1,14 @@
+CHARSET=: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ '
+NPROG=:   100                            NB. number of progeny (C)
+MRATE=:   0.05                           NB. mutation rate
+
+create  =: (?@$&$ { ])&CHARSET           NB. creates random list from charset of same shape as y
+fitness =: +/@:~:"1
+copy    =: # ,:
+mutate  =: &(>: $ ?@$ 0:)(`(,: create))} NB. adverb
+select  =: ] {~ (i. <./)@:fitness        NB. select fittest member of population
+
+nextgen =: select ] , [: MRATE mutate NPROG copy ]
+while   =: conjunction def '(] , (u {:))^:(v {:)^:_ ,:'
+
+evolve=: nextgen while (0 < fitness) create

Task/Evolutionary-algorithm/J/evolutionary-algorithm-2.j

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+   filter=: {: ,~ ({~ i.@>.&.(%&20)@#)   NB. take every 20th and last item
+   filter evolve 'METHINKS IT IS LIKE A WEASEL'
+XXURVQXKQXDLCGFVICCUA NUQPND
+MEFHINVQQXT IW LIKEUA WEAPEL
+METHINVS IT IW LIKEUA WEAPEL
+METHINKS IT IS LIKE A WEASEL

Task/Evolutionary-algorithm/J/evolutionary-algorithm-3.j

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+CHARSET=: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ '
+NPROG=:   100                             NB. "C" from specification
+
+fitness=: +/@:~:"1
+select=: ] {~ (i. <./)@:fitness           NB. select fittest member of population
+populate=: (?@$&# { ])&CHARSET            NB. get random list from charset of same length as y
+log=: [: smoutput [: ;:inv (('#';'fitness: ';'; ') ,&.> ":&.>)
+
+mutate=: dyad define
+  idxmut=. I. x >: (*/$y) ?@$ 0
+  (populate idxmut) idxmut"_} y
+)
+
+evolve=: monad define
+  target=. y
+  parent=. populate y
+  iter=. 0
+  mrate=. %#y
+  while. 0 < val=. target fitness parent do.
+    if. 0 = 50|iter do. log iter;val;parent end.
+    iter=. iter + 1
+    progeny=. mrate mutate NPROG # ,: parent  NB. create progeny by mutating parent copies
+    parent=. target select parent,progeny     NB. select fittest parent for next generation
+  end.
+  log iter;val;parent
+  parent
+)

Task/Evolutionary-algorithm/J/evolutionary-algorithm-4.j

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+   evolve 'METHINKS IT IS LIKE A WEASEL'
+#0 fitness: 27 ; YGFDJFTBEDB FAIJJGMFKDPYELOA
+#50 fitness: 2 ; MEVHINKS IT IS LIKE ADWEASEL
+#76 fitness: 0 ; METHINKS IT IS LIKE A WEASEL
+METHINKS IT IS LIKE A WEASEL