36 lines
1.1 KiB
Python
36 lines
1.1 KiB
Python
from string import ascii_uppercase
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from random import choice, random
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target = list("METHINKS IT IS LIKE A WEASEL")
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charset = ascii_uppercase + ' '
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parent = [choice(charset) for _ in range(len(target))]
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minmutaterate = .09
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C = range(100)
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perfectfitness = float(len(target))
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def fitness(trial):
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'Sum of matching chars by position'
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return sum(t==h for t,h in zip(trial, target))
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def mutaterate():
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'Less mutation the closer the fit of the parent'
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return 1-((perfectfitness - fitness(parent)) / perfectfitness * (1 - minmutaterate))
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def mutate(parent, rate):
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return [(ch if random() <= rate else choice(charset)) for ch in parent]
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def que():
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'(from the favourite saying of Manuel in Fawlty Towers)'
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print ("#%-4i, fitness: %4.1f%%, '%s'" %
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(iterations, fitness(parent)*100./perfectfitness, ''.join(parent)))
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iterations = 0
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while parent != target:
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rate = mutaterate()
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iterations += 1
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if iterations % 100 == 0: que()
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copies = [ mutate(parent, rate) for _ in C ] + [parent]
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parent = max(copies, key=fitness)
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print ()
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que()
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