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#! /usr/bin/env python
"""
another demo that cracks a secret string
This one uses the discrete int gene
"""
from pygene.gene import FloatGene, IntGene, rndPair
from pygene.gamete import Gamete
from pygene.organism import Organism, MendelOrganism
from pygene.population import Population
# this is the string that our organisms
# are trying to evolve into
teststr = "hackthis"
teststrlen = len(teststr)
# convert the string into a list of floats, where
# each float is the ascii value of the corresponding
# char
teststrNums = [float(ord(c)) for c in teststr]
# generate a set of 'gene names', one for each char in the string
geneNames = []
for i in range(len(teststr)):
geneNames.append("c%s" % i)
# the alphabet from which we're picking genes' values
alphabet = "abcdefghijklmnopqrstuvwxyz"
# derive a gene which holds a character, and can
# mutate into another character
class HackerGene(IntGene):
mutProb = 0.1
mutAmt = 10.0
randMin = 0x0
randMax = 0xff
# generate a genome, one gene for each char in the string
genome = {}
for i in range(len(teststr)):
genome[str(i)] = HackerGene
# an organism that evolves towards the required string
class StringHacker(MendelOrganism):
#class StringHacker(Organism):
genome = genome
def __repr__(self):
"""
Return the gene values as a string
"""
chars = []
for k in xrange(self.numgenes):
n = self[str(k)]
#print "n=%s" % repr(n)
c = str(chr(n))
chars.append(c)
return ''.join(chars)
def fitness(self):
"""
calculate fitness, as the sum of the squares
of the distance of each char gene from the
corresponding char of the target string
"""
diffs = 0
guess = str(self)
for i in xrange(self.numgenes):
x0 = teststrNums[i]
x1 = ord(guess[i])
diffs += (x1 - x0) ** 2
return diffs
class StringHackerPopulation(Population):
initPopulation = 10
species = StringHacker
# cull to this many children after each generation
childCull = 10
# number of children to create after each generation
childCount = 40
# start with a population of 10 random organisms
ph = StringHackerPopulation()
def main(nfittest=10, nkids=100):
i = 0
while True:
b = ph.best()
print "generation %s: %s best=%s average=%s)" % (
i, repr(b), b.get_fitness(), ph.fitness())
if b.get_fitness() <= 0:
print "cracked!"
break
i += 1
ph.gen()
if __name__ == '__main__':
main()
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