1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
### http://www.electricmonk.nl/log/2011/09/28/evolutionary-algorithm-evolving-hello-world/
import random
import string
from time import sleep
source = "jiKnp4bqpmAbp"
target = "Hello, World!"
def fitness(source, target):
fitval = 0
for i in range(0, len(source)):
fitval += (ord(target[i]) - ord(source[i])) ** 2
return(fitval)
GENSIZE = 20
genepool = []
for i in range(0, GENSIZE):
dna = [random.choice(string.printable[:-5]) for j in range(0, len(target))]
fit = fitness(dna, target)
candidate = {'dna': dna, 'fitness': fit }
genepool.append(candidate)
def mutate(parent1, parent2):
child_dna = parent1['dna'][:]
# Mix both DNAs
start = random.randint(0, len(parent2['dna']) - 1)
stop = random.randint(0, len(parent2['dna']) - 1)
if start > stop:
stop, start = start, stop
child_dna[start:stop] = parent2['dna'][start:stop]
# Mutate one position
charpos = random.randint(0, len(child_dna) - 1)
child_dna[charpos] = chr(ord(child_dna[charpos]) + random.randint(-1,1))
child_fitness = fitness(child_dna, target)
return({'dna': child_dna, 'fitness': child_fitness})
def random_parent(genepool):
wRndNr = random.random() * random.random() * (GENSIZE - 1)
wRndNr = int(wRndNr)
return(genepool[wRndNr])
i = 0
while True:
i += 1
genepool.sort(key=lambda candidate: candidate['fitness'])
print "%5i %5i %14s" % (i, genepool[0]['fitness'], ''.join(genepool[0]['dna']))
sleep(0.1)
if genepool[0]['fitness'] == 0:
break
parent1 = random_parent(genepool)
parent2 = random_parent(genepool)
child = mutate(parent1, parent2)
if child['fitness'] < genepool[-1]['fitness']:
genepool[-1] = child
|
