void selection(Individual population[]) { int i; int totalFitness = 0; int selected[POPULATION_SIZE]; int cumFitness[POPULATION_SIZE]; int sum = 0; for (i = 0; i < POPULATION_SIZE; i++) { totalFitness += population[i].fitness; } for (i = 0; i < POPULATION_SIZE; i++) { cumFitness[i] = sum + population[i].fitness / (double)totalFitness; sum = cumFitness[i]; } Individual newPopulation[POPULATION_SIZE]; // 新种群数组 for (i = 0; i < POPULATION_SIZE; i++) { double r = (rand() % 100) / 100.0; int j; for (j = 0; j < POPULATION_SIZE; j++) { if (r <= cumFitness[j]) { selected[i] = j; break; } } } // for (i = 0; i < POPULATION_SIZE; i++) { // population[i] = population[selected[i]];//数组越界溢出,可扩大堆栈容量来处理,这里采用增加新的种群数组 for (i = 0; i < POPULATION_SIZE; i++) { newPopulation[i] = population[selected[i]];//异常仍未解决? } for (i = 0; i < POPULATION_SIZE; i++) { population[i] = newPopulation[i]; } }
时间: 2024-04-09 21:31:03 浏览: 23
这段代码是一个遗传算法中的选择操作。该函数根据个体的适应度值选择个体,并将选择的个体复制到新的种群中。
首先,计算种群中所有个体的适应度之和。然后,计算每个个体被选择的累积概率。接下来,生成一个随机数r,并根据r的值选择个体。选择的个体被存储在selected数组中。
由于原始种群数组population可能会越界溢出,所以创建了一个新的种群数组newPopulation。将选中的个体复制到newPopulation中。
最后,将newPopulation中的个体复制回原始种群数组population。
需要注意的是,这段代码中有一段被注释掉的代码。这段代码将原始种群数组population直接赋值为选中的个体,可能导致数组越界溢出。所以建议使用新的种群数组newPopulation来存储选中的个体。
相关问题
题目为: min [𝑧=𝑥_1^2+𝑥_2^2+3𝑥_3^2+4𝑥_4^2+2𝑥_5^2−8𝑥_1−2𝑥_2−2𝑥_3−𝑥_4−2𝑥_5 ] 𝑠.𝑡.{ 0 <= x_i <= 99,且x_i 为整数,i =1,2,3,...,5, 𝑥_1+𝑥_2 +𝑥_3 +𝑥_4 +𝑥_5≤400, 𝑥_1+2𝑥_2 +2𝑥_3 +𝑥_4 +6𝑥_5≤800, 2𝑥_1+𝑥_2 +6𝑥_3 <= 200, 𝑥_3+𝑥_4 +5𝑥_5≤200 } 用matlab语言实现遗传算法求解非线性规划问题(不用ga函数)
这个非线性规划问题可以使用遗传算法来求解。下面是用MATLAB语言实现遗传算法的代码:
```matlab
% 参数设置
popSize = 100; % 种群大小
chromLength = 5; % 染色体长度
maxGen = 100; % 最大迭代次数
pc = 0.8; % 交叉概率
pm = 0.01; % 变异概率
% 初始化种群
population = randi([0, 99], popSize, chromLength);
% 迭代寻优
for gen = 1:maxGen
% 计算适应度值
fitness = evaluateFitness(population);
% 选择操作(轮盘赌选择)
selectedPopulation = selection(population, fitness);
% 交叉操作
offspringPopulation = crossover(selectedPopulation, pc);
% 变异操作
mutatedPopulation = mutation(offspringPopulation, pm);
% 合并父代和子代种群
population = [population; mutatedPopulation];
% 保留最优个体
[~, idx] = sort(evaluateFitness(population), 'descend');
population = population(idx(1:popSize), :);
end
% 输出结果
bestIndividual = population(1, :);
bestFitness = evaluateFitness(bestIndividual);
disp(['最优解:', num2str(bestIndividual)]);
disp(['最优适应度值:', num2str(bestFitness)]);
% 计算适应度值的函数
function fitness = evaluateFitness(population)
[n, ~] = size(population);
fitness = zeros(n, 1);
for i = 1:n
x = population(i, :);
fitness(i) = x(1)^2 + x(2)^2 + 3*x(3)^2 + 4*x(4)^2 + 2*x(5)^2 - 8*x(1) - 2*x(2) - 2*x(3) - x(4) - 2*x(5);
end
end
% 轮盘赌选择操作
function selectedPopulation = selection(population, fitness)
[n, ~] = size(population);
totalFitness = sum(fitness);
probability = fitness / totalFitness;
cumulativeProbability = cumsum(probability);
selectedPopulation = zeros(n, size(population, 2));
for i = 1:n
r = rand();
idx = find(cumulativeProbability >= r, 1);
selectedPopulation(i, :) = population(idx, :);
end
end
% 交叉操作
function offspringPopulation = crossover(selectedPopulation, pc)
[n, chromLength] = size(selectedPopulation);
offspringPopulation = zeros(n, chromLength);
for i = 1:2:n-1
if rand() < pc
crossoverPoint = randi([2, chromLength-1]);
offspringPopulation(i, :) = [selectedPopulation(i, 1:crossoverPoint), selectedPopulation(i+1, crossoverPoint+1:end)];
offspringPopulation(i+1, :) = [selectedPopulation(i+1, 1:crossoverPoint), selectedPopulation(i, crossoverPoint+1:end)];
else
offspringPopulation(i, :) = selectedPopulation(i, :);
offspringPopulation(i+1, :) = selectedPopulation(i+1, :);
end
end
end
% 变异操作
function mutatedPopulation = mutation(offspringPopulation, pm)
[n, chromLength] = size(offspringPopulation);
mutatedPopulation = offspringPopulation;
for i = 1:n
for j = 1:chromLength
if rand() < pm
mutatedPopulation(i, j) = randi([0, 99]);
end
end
end
end
```
上述代码实现了遗传算法的基本框架,包括初始化种群、计算适应度值、选择操作、交叉操作和变异操作等。你可以将问题中的目标函数和约束条件替换到代码中的相应部分,然后运行代码即可求解该非线性规划问题。
用C语言代码实现遗传算法
以下是一个简单的用C语言实现遗传算法的示例代码:
```c
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define POPULATION_SIZE 10
#define CHROMOSOME_LENGTH 5
#define MAX_GENERATIONS 100
#define MUTATION_RATE 0.1
typedef struct {
int genes[CHROMOSOME_LENGTH];
int fitness;
} Individual;
int calculateFitness(Individual individual) {
int fitness = 0;
// 计算适应度函数,根据具体问题进行定义
// 这里简单地求解二进制数的值作为适应度
for (int i = 0; i < CHROMOSOME_LENGTH; i++) {
fitness += individual.genes[i] << (CHROMOSOME_LENGTH - 1 - i);
}
return fitness;
}
void initializePopulation(Individual population[]) {
// 随机初始化种群
for (int i = 0; i < POPULATION_SIZE; i++) {
for (int j = 0; j < CHROMOSOME_LENGTH; j++) {
population[i].genes[j] = rand() % 2;
}
population[i].fitness = calculateFitness(population[i]);
}
}
Individual selectParent(Individual population[]) {
// 轮盘赌选择父代
int totalFitness = 0;
for (int i = 0; i < POPULATION_SIZE; i++) {
totalFitness += population[i].fitness;
}
int randomFitness = rand() % totalFitness;
int sumFitness = 0;
for (int i = 0; i < POPULATION_SIZE; i++) {
sumFitness += population[i].fitness;
if (sumFitness >= randomFitness) {
return population[i];
}
}
return population[POPULATION_SIZE - 1];
}
Individual crossover(Individual parent1, Individual parent2) {
// 单点交叉生成子代
int crossoverPoint = rand() % CHROMOSOME_LENGTH;
Individual child;
for (int i = 0; i < CHROMOSOME_LENGTH; i++) {
if (i < crossoverPoint) {
child.genes[i] = parent1.genes[i];
} else {
child.genes[i] = parent2.genes[i];
}
}
child.fitness = calculateFitness(child);
return child;
}
void mutate(Individual* individual) {
// 突变
for (int i = 0; i < CHROMOSOME_LENGTH; i++) {
if ((double)rand() / RAND_MAX < MUTATION_RATE) {
individual->genes[i] = !individual->genes[i];
}
}
individual->fitness = calculateFitness(*individual);
}
Individual findBestIndividual(Individual population[]) {
// 找到最优个体
int bestFitness = population[0].fitness;
int bestIndex = 0;
for (int i = 1; i < POPULATION_SIZE; i++) {
if (population[i].fitness > bestFitness) {
bestFitness = population[i].fitness;
bestIndex = i;
}
}
return population[bestIndex];
}
void printIndividual(Individual individual) {
// 打印个体的基因和适应度
for (int i = 0; i < CHROMOSOME_LENGTH; i++) {
printf("%d ", individual.genes[i]);
}
printf("-> %d\n", individual.fitness);
}
int main() {
srand(time(NULL));
Individual population[POPULATION_SIZE];
initializePopulation(population);
for (int generation = 0; generation < MAX_GENERATIONS; generation++) {
Individual newPopulation[POPULATION_SIZE];
for (int i = 0; i < POPULATION_SIZE; i++) {
Individual parent1 = selectParent(population);
Individual parent2 = selectParent(population);
Individual child = crossover(parent1, parent2);
mutate(&child);
newPopulation[i] = child;
}
for (int i = 0; i < POPULATION_SIZE; i++) {
population[i] = newPopulation[i];
}
printf("Generation %d: ", generation + 1);
printIndividual(findBestIndividual(population));
}
return 0;
}
```
以上代码是一个简单的遗传算法的实现示例。你可以根据具体问题的需求进行修改和扩展。
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