使用遗传算法求解最大化函数f(x)=x+10sin(5x)+7cos(4x)的x,其中x ∈ [ 0 , 10 ],用matlab进行编写
时间: 2023-10-07 20:11:02 浏览: 125
遗传算法实例
以下是使用遗传算法求解最大化函数f(x)=x+10sin(5x)+7cos(4x)的x,其中x ∈ [ 0 , 10 ] 的 Matlab 代码实现:
```matlab
% 定义问题
function y = f(x)
y = x + 10*sin(5*x) + 7*cos(4*x);
end
% 定义遗传算法参数
pop_size = 50; % 种群大小
chrom_length = 22; % 染色体长度
pc = 0.6; % 交叉概率
pm = 0.01; % 变异概率
max_iter = 100; % 最大迭代次数
% 初始化种群
function pop = init_pop()
pop = repmat('0', pop_size, chrom_length);
for i = 1:pop_size
for j = 1:chrom_length
if rand < 0.5
pop(i,j) = '0';
else
pop(i,j) = '1';
end
end
end
end
% 适应度函数计算
function fit = fitness(chrom)
x = bin2dec(chrom) / (2^chrom_length-1) * 10;
fit = f(x);
end
% 轮盘赌选择算子
function chrom = select(pop, fitness_sum)
rand_num = rand * fitness_sum;
for i = 1:pop_size
rand_num = rand_num - fitness(pop(i,:));
if rand_num <= 0
chrom = pop(i,:);
break;
end
end
end
% 单点交叉算子
function [child1, child2] = crossover(parent1, parent2)
pos = randi(chrom_length-1);
child1 = [parent1(1:pos), parent2(pos+1:end)];
child2 = [parent2(1:pos), parent1(pos+1:end)];
end
% 随机变异算子
function chrom = mutation(chrom)
pos = randi(chrom_length);
if chrom(pos) == '0'
chrom(pos) = '1';
else
chrom(pos) = '0';
end
end
% 遗传算法求解最大化函数f(x)
function [best_x, best_f] = GA()
pop = init_pop();
for i = 1:max_iter
% 计算适应度函数值
fitness_list = zeros(pop_size, 1);
for j = 1:pop_size
fitness_list(j) = fitness(pop(j,:));
end
fitness_sum = sum(fitness_list);
% 选择操作
new_pop = repmat('0', pop_size*2, chrom_length);
for j = 1:pop_size
parent1 = select(pop, fitness_sum);
parent2 = select(pop, fitness_sum);
% 交叉操作
if rand < pc
[child1, child2] = crossover(parent1, parent2);
else
child1 = parent1;
child2 = parent2;
end
% 变异操作
if rand < pm
child1 = mutation(child1);
end
if rand < pm
child2 = mutation(child2);
end
new_pop((j-1)*2+1,:) = child1;
new_pop((j-1)*2+2,:) = child2;
end
pop = new_pop;
end
% 选择最优解
best_f = -inf;
for i = 1:pop_size*2
x = bin2dec(pop(i,:)) / (2^chrom_length-1) * 10;
f_val = f(x);
if f_val > best_f
best_x = x;
best_f = f_val;
end
end
end
% 调用遗传算法求解
[best_x, best_f] = GA();
fprintf('最优解:x=%.5f,f(x)=%.5f\n', best_x, best_f);
```
在 Matlab 中运行上述代码,即可得到最优解 x 和对应的最大化函数值 f(x)。
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