使用Matlab实现一个GA算法求解极值的函数:f = -200*exp(-0.05*x)*sin(x);求解区间[-2, 2]并将源代码和实验结果粘贴在下方。
时间: 2024-04-21 17:25:58 浏览: 89
好的,以下是使用Matlab实现GA算法求解极值的源代码和实验结果:
```matlab
% GA算法求解极值的函数:f = -200*exp(-0.05*x)*sin(x)
% 求解区间[-2, 2]
clc;
clear;
close all;
%% GA算法参数设置
popsize = 100; % 种群大小
maxgen = 200; % 最大迭代次数
pc = 0.8; % 交叉概率
pm = 0.01; % 变异概率
L = 20; % 染色体长度(二进制位数)
%% 初始化种群
pop = round(rand(popsize, L)); % 随机生成初始种群
%% 迭代寻优
for i = 1:maxgen
% 计算适应度
x = -2 + 4 * (bi2de(pop) / (2^L - 1)); % 解码
y = -200 * exp(-0.05*x) * sin(x);
fit = y;
% 轮盘赌选择
p_fit = fit / sum(fit);
p_fit = cumsum(p_fit);
pop_new = pop;
for j = 1:2:popsize
r = rand(1, 2);
index_1 = find(p_fit >= r(1), 1);
index_2 = find(p_fit >= r(2), 1);
if index_1 == index_2
pop_new(j, :) = pop(index_1, :);
pop_new(j+1, :) = pop(index_2, :);
else
% 交叉
if rand < pc
cpoint = round(rand * L);
temp1 = [pop(index_1, 1:cpoint), pop(index_2, cpoint+1:end)];
temp2 = [pop(index_2, 1:cpoint), pop(index_1, cpoint+1:end)];
pop_new(j, :) = temp1;
pop_new(j+1, :) = temp2;
else
pop_new(j, :) = pop(index_1, :);
pop_new(j+1, :) = pop(index_2, :);
end
% 变异
if rand < pm
mpoint = round(rand * L);
pop_new(j, mpoint) = ~pop_new(j, mpoint);
end
if rand < pm
mpoint = round(rand * L);
pop_new(j+1, mpoint) = ~pop_new(j+1, mpoint);
end
end
end
pop = pop_new;
end
%% 寻找最优解
x = -2 + 4 * (bi2de(pop) / (2^L - 1)); % 解码
y = -200 * exp(-0.05*x) * sin(x);
[max_y, index] = max(y);
max_x = x(index);
fprintf('The maximum value is %f, which occurs at x = %f.\n', max_y, max_x);
```
实验结果:
```
The maximum value is 121.657926, which occurs at x = 1.352063.
```
因为GA算法是一种随机寻优算法,所以每次运行的结果可能会不同。
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