22 lines
1.0 KiB
Plaintext
22 lines
1.0 KiB
Plaintext
target = "METHINKS IT IS LIKE A WEASEL";
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alphabet = CharacterRange["A", "Z"]~Join~{" "};
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fitness = HammingDistance[target, #] &;
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Mutate[parent_String, rate_: 0.01, fertility_Integer: 25] := Module[
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{offspring, kidfits, gen = 0, alphabet = CharacterRange["A", "Z"]~Join~{" "}},
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offspring = ConstantArray[Characters[parent], fertility];
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Table[
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If[RandomReal[] <= rate, offspring[[j, k]] = RandomChoice[alphabet]],
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{j, fertility}, {k, StringLength@parent}
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];
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offspring = StringJoin[#] & /@ offspring;
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kidfits = fitness[#] & /@ Flatten[{offspring, parent}];
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Return[offspring[[First@Ordering[kidfits]]]];
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];
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mutationRate = 0.02;
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parent = StringJoin[ alphabet[[RandomInteger[{1, Length@alphabet}, StringLength@target]]] ];
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results = NestWhileList[Mutate[#, mutationRate, 100] &, parent, fitness[#] > 0 &];
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fits = fitness[#] & /@ results;
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results = Transpose[{results, fits}];
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TableForm[results[[;; ;; 2]], TableHeadings->{Range[1, Length@results, 2],{"String","Fitness"}}, TableSpacing -> {1, 2}]
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