# w/ W" k6 e3 z/ P; J+ W假设个体a、b的基因是2 n$ e0 w+ u- l' h. Q. V% U
, F& x, q& U; ^3 D1 ?a = [1, 0, 0, 0, 0, 1, 1, 1, 0, 0]$ L* @6 [3 I3 o6 {( Q, n) D: P
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b = [0, 0, 0, 1, 1, 0, 1, 1, 1, 1]; Q3 t& I* b' ]1 X1 Q
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这两个个体发生基因交换的概率pc = 0.6.如果要发生基因交换,则产生一个随机数point表示基因交换的位置,假设point = 4,则: ; `, v2 ?! g) M* _% N" V, v5 ]) _/ K# d+ W
a = [1, 0, 0, 0, 0, 1, 1, 1, 0, 0] 1 K* m, x3 a. s) ]& X% N9 e5 `1 q
b = [0, 0, 0, 1, 1, 0, 1, 1, 1, 1]1 r) R; ]: ?4 a8 I
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交换后为:: b Q) T: U8 x. P& n8 `* \* h
: C, `, `0 b3 O6 b
a = [1, 0, 0, 0, 1, 0, 1, 1, 1, 1] 4 p' i4 Y0 L7 y( w! @1 n# X0 p' i; B5 W4 P$ f: `2 {
b = [0, 0, 0, 1, 0, 1, 1, 1, 0, 0]7 O. ` ~7 P$ J+ F; C
7 J! v* z% T4 J. a( T9 l5 N6、突变# i+ Z2 ^$ J8 ^, t! E
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遍历每一个个体,基因的每一位发生突变(0变为1,1变为0)的概率为0.001.突变可以增加解空间1 c' C+ M: C' B: A F* \0 Y5 R% p
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二、代码 ~6 f. n- ?- g2 S! cdef b2d(b): #将二进制转化为十进制 x∈[0,10] 3 V( J) S6 J( U3 S! ~4 _ t = 0 : n- ^* \; s: [ for j in range(len(b)): $ u/ r. U; h: `! q( H2 ] t += b[j] * (math.pow(2, j))0 _% H6 o% `9 t# Z8 e3 C
t = t * 10 / 1023 ! j; Z1 b( ^+ { return t ( V: B% C: |* J9 `+ ~. v1 u% O* { * M7 A; s: P; z- a9 i8 M, E9 R/ Ypopsize = 50 #种群的大小 2 b3 ^! z$ c5 w" [#用遗传算法求函数最大值:" e1 F2 Q T% @, E `" m, M
#f(x)=10*sin(5x)+7*cos(4x) x∈[0,10] " [( {: s$ G9 _' g7 j) l2 G: w! ]3 f) A4 k
chromlength = 10 #基因片段的长度7 T, ]/ t/ M" G# w9 O# K" p
pc = 0.6 #两个个体交叉的概率 1 z/ \: J H/ ] o) D( l" rpm = 0.001; #基因突变的概率 / U4 |9 I$ `) z# w4 H2 _9 @5 l3 o; c/ xresults = [[]] " U$ t3 C: Z6 {0 Abestindividual = [] 9 ]% K! e8 c! Z9 A1 g: ubestfit = 0# I8 U2 C, j& ^% X$ P; E* O
fitvalue = [] . J1 F- E3 t$ ?6 W* \0 qtempop = [[]]& e# M5 W8 Y; p' I4 q
pop = [[0, 1, 0, 1, 0, 1, 0, 1, 0, 1] for i in range(popsize)]3 V! o8 A' P/ Z0 c1 g w
for i in range(100): #繁殖100代 9 U! l; Y! {, Z" |/ n; j objvalue = calobjvalue(pop) #计算目标函数值" I/ y; @! |7 {% J( w
fitvalue = calfitvalue(objvalue); #计算个体的适应值 4 q1 Y& ~) P, o* ~/ E$ | [bestindividual, bestfit] = best(pop, fitvalue) #选出最好的个体和最好的函数值 ! N4 I" T+ O: k# ?4 k7 R results.append([bestfit,b2d(bestindividual)]) #每次繁殖,将最好的结果记录下来' X, Q, Z/ y# l- A4 ^
selection(pop, fitvalue) #自然选择,淘汰掉一部分适应性低的个体 * l4 m! S# E- H crossover(pop, pc) #交叉繁殖 4 ~4 X+ n& d6 q- G J' E2 j mutation(pop, pc) #基因突变2 O% g0 m& Q( p1 c: u9 i, }5 m5 N. Z
/ n! [) a7 O1 m; M* H 1 Q" z7 n& C: Z1 ?& [0 D% _results.sort() 5 U8 k8 A6 e+ uprint(results[-1]) #打印函数最大值和对应的3 ], l' P1 D0 l1 H4 M
def calfitvalue(objvalue):#转化为适应值,目标函数值越大越好,负值淘汰。0 ^& z3 H8 @/ n& _
fitvalue = [] & k% U% p4 R0 e- l2 t temp = 0.0 0 T! S8 l! D$ b1 E) S Cmin = 0;+ e; V C6 F6 m7 V; E* D
for i in range(len(objvalue)): ) Y. _- K0 y% G if(objvalue + Cmin > 0):9 ?. I4 y$ l) h3 Y* E; I5 a
temp = Cmin + objvalue 6 Y0 w: R4 w: _# }' _7 e else: : {9 q) S. F' t temp = 0.0 4 e0 }+ j# t/ c2 P# b2 ` fitvalue.append(temp)- {5 h7 p2 T- ?3 ~1 `7 t2 q4 w
return fitvalue $ V2 O' Z' i L! Dimport math& ?) s0 |1 g: |' `1 r. E: B+ E
2 x9 \$ k5 ]: \2 L; d* s5 |def decodechrom(pop): #将种群的二进制基因转化为十进制(0,1023)7 i% W3 K* T& S$ s2 @
temp = []; ' E) d7 F4 y. M for i in range(len(pop)):8 ~3 q( G( K: m4 r1 Y% I& y
t = 0; 8 [$ [2 e; C& ~: n. t. g: z for j in range(10):& R3 i2 l0 I* G
t += pop[j] * (math.pow(2, j)) v P. n" X5 w1 M; G temp.append(t)5 T( Q7 `3 Z. [' @- m' V+ K
return temp) U1 D1 a8 d6 I
% E; P, {1 Y# T/ E1 l4 ldef calobjvalue(pop): #计算目标函数值! C8 F7 u. q4 @8 {
temp1 = [];( s" l+ O% }% d, W! l6 ]
objvalue = []; ( O, j- S z& w4 g3 x2 |$ }; _9 i$ \ temp1 = decodechrom(pop)5 c9 s4 B+ Z7 Q9 j8 K
for i in range(len(temp1)): - x' Y$ @# H( ^ s% W- y x = temp1 * 10 / 1023 #(0,1023)转化为 (0,10)1 G2 _" n, W* l8 |' X) S
objvalue.append(10 * math.sin(5 * x) + 7 * math.cos(4 * x)) 0 D3 I* [1 w$ c$ B9 K6 L4 o* U7 ~! G return objvalue #目标函数值objvalue[m] 与个体基因 pop[m] 对应 $ K9 A4 W3 D9 ~2 m& ?def best(pop, fitvalue): #找出适应函数值中最大值,和对应的个体- b6 p' n3 H' }3 e' g
px = len(pop). v2 J/ a- w" H
bestindividual = []' [8 d0 P# i* {3 K U- i+ D9 s
bestfit = fitvalue[0]$ n6 @. I3 |7 b. b B, ]
for i in range(1,px): 2 H* u' Z# u, Y4 Y8 o0 P3 y& E+ b if(fitvalue > bestfit): " J4 k' p% s0 Z( e* p" i bestfit = fitvalue % l9 f& }/ M0 i bestindividual = pop & ]3 _; m% _4 r. P- Q return [bestindividual, bestfit] # ~3 m. K: C4 |- ximport random# I( X$ P/ \; R* O
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def sum(fitvalue):4 w7 c8 I9 i4 `, C' p( p
total = 09 V9 M" R: E$ N
for i in range(len(fitvalue)): , L0 [" u8 f7 j$ ~- W total += fitvalue # C* |. N0 y2 E3 T! w2 B9 t8 Y return total + Q7 K% k; n: m- ?7 f( x 0 i$ W* G0 a* a5 t$ x! X0 Bdef cumsum(fitvalue):% C Y: O5 ]# V" p
for i in range(len(fitvalue)): 9 G0 N% o3 s" m% h/ w t = 0;0 W# k# x4 R0 H' e$ m
j = 0; 4 d% ~) M1 P6 c# L) Q while(j <= i):& n9 j" X1 P, V
t += fitvalue[j]$ t- y2 t1 `! R; U% s3 a
j = j + 1 $ b7 q8 F5 M, l4 O% ?/ G! u fitvalue = t; # c7 y" G. Y! i& k$ z5 g9 b: ? & _0 p5 B) p7 G- |; adef selection(pop, fitvalue): #自然选择(轮盘赌算法) " |+ t* Q. T6 Y newfitvalue = [] 5 }, X6 n- a2 D! a8 n- D/ C totalfit = sum(fitvalue): v; H( Q. l) _2 b
for i in range(len(fitvalue)): 4 p e Q, `& v# S' X; d l newfitvalue.append(fitvalue / totalfit) 4 G* T! f1 H- h cumsum(newfitvalue) + A: w4 u. k: X# { ms = []; . m" o1 I& ` i, E1 y5 W poplen = len(pop)7 ]! V* e8 h9 T
for i in range(poplen): & T* n- M7 X$ {- V9 w ms.append(random.random()) #random float list ms) B9 @& ?, k, f
ms.sort(); O, F- W8 Q2 j
fitin = 00 a- l C2 u4 d# h6 q H$ C+ ^) s
newin = 0 $ Z8 l' a# H$ i' X$ @5 { newpop = pop4 x: X, F, ^! i1 j
while newin < poplen:+ @: p. g7 X% F" J7 L8 }3 s |
if(ms[newin] < newfitvalue[fitin]):7 p2 M/ U: R% l K1 k3 \
newpop[newin] = pop[fitin] 4 `( T- F; q1 B, ^9 U newin = newin + 1. C6 q( H" S9 @) f1 z
else:& @2 g, B& I3 _- F7 D) Q5 m
fitin = fitin + 1 $ v0 b4 q; t, \6 F pop = newpop 3 J }- R3 e' `( t# `import random 7 z. Q% G1 A# H" A5 y# u' t W6 [* z; \7 e- t V+ P
def crossover(pop, pc): #个体间交叉,实现基因交换 1 o% ^! ]( A, N! A" E poplen = len(pop)6 C; W5 w2 H3 j
for i in range(poplen - 1): 1 K0 W1 U |, L( j if(random.random() < pc): : i2 \" o! p1 n5 W cpoint = random.randint(0,len(pop[0]))# G5 H0 @) T Q0 G1 B' A' |( N
temp1 = []6 W, X) F+ U- x, u) @; ]
temp2 = [] ! a: l$ Z. J3 M9 g2 l X temp1.extend(pop[0 : cpoint]) ' ?- |2 _ P; j' l) S temp1.extend(pop[i+1][cpoint : len(pop)])! P ^& y2 b: l
temp2.extend(pop[i+1][0 : cpoint]); G5 m2 w3 H% N/ e1 o2 S8 l
temp2.extend(pop[cpoint : len(pop)])2 L }2 z* ^% ~+ B: A- n: N( v! F& ~
pop = temp1 $ D3 Z9 X- R0 Z" V: t f3 @6 ~ pop[i+1] = temp28 H& ~1 n! c6 v! q8 ?0 d" C
import random: f0 |# G$ Y( G
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def mutation(pop, pm): #基因突变 9 c, b' V3 V1 s, c px = len(pop) ( V# m. v' O% \8 {* t) P py = len(pop[0]) 6 {- W0 h9 x. y! H" _7 X$ O7 [) W5 t% H
for i in range(px): ! I1 }( A1 q8 F5 A' Z- U if(random.random() < pm):: f5 I% e' p' D9 q
mpoint = random.randint(0,py-1)/ q0 y$ w: f s, P9 g; @) [9 Y; @
if(pop[mpoint] == 1): 6 d" T) U( n% O' q; l& o6 X& m pop[mpoint] = 03 d* f5 I% I4 B6 b% i0 L
else:% w [0 w( m$ F/ v" y) j Q( R
pop[mpoint] = 1 * A- P2 K2 r0 n. w % Z; }0 p: J, z9 g% h5 H3 y) B+ N. o. p" T* ]5 Y
———————————————— 0 M* ^2 M4 m0 \' O) A版权声明:本文为CSDN博主「simon-zhao」的原创文章,遵循CC 4.0 BY-SA版权协议,转载请附上原文出处链接及本声明。* E+ P; Q- ~& ^- |
原文链接:https://blog.csdn.net/u010902721/article/details/23531359 ( }9 k3 E. r9 h5 L" V8 \, p0 \5 w9 q2 A6 h+ D: H4 M. O+ p
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