双倍体遗传算法的python代码
时间: 2024-10-24 07:18:45 浏览: 43
大数据-算法-改进双倍体遗传算法在作业车间调度中的应用研究.pdf
双倍体遗传算法是一种优化搜索技术,它结合了遗传算法的特性(如自然选择、交叉和突变)以及二进制编码的双倍体策略。在Python中编写这样的算法,通常包括以下几个步骤:
1. 初始化种群:创建一个包含随机生成个体(即解决方案候选)的群体,每个个体由二进制编码表示。
```python
import numpy as np
def initialize_population(population_size, chromosome_length):
return [np.random.randint(0, 2, chromosome_length) for _ in range(population_size)]
```
2.适应度函数:定义目标函数,用于评估个体的优劣。
```python
def fitness_function(individual):
# 这里替换为你具体的优化问题的目标计算
return -individual.sum() # 假设我们正在最小化一个求和问题
```
3.双倍体操作:选择两个优秀的个体,通过交叉和复制操作生成新的后代。
```python
def mate(parent1, parent2):
offspring = []
crossover_point = np.random.randint(1, len(parent1))
child = np.concatenate((parent1[:crossover_point], parent2[crossover_point:]))
offspring.extend([child, parent1]) # 添加复制的亲代
return offspring
```
4.变异操作:为了增加多样性,对一些个体进行随机改变。
```python
def mutate(individual, mutation_rate):
mutated_individual = individual.copy()
np.random.binomial(1, mutation_rate, size=mutated_individual.shape).astype(bool)
return mutated_individual
```
5.迭代过程:重复上述步骤直到达到预设的停止条件,比如达到最大迭代次数或者找到足够好的解。
```python
def double_phase_ga(population, population_size, crossover_rate, mutation_rate, max_iterations):
for _ in range(max_iterations):
# 筛选和交叉
fitness_scores = [fitness_function(ind) for ind in population]
elite = sorted(zip(population, fitness_scores), key=lambda x: x[1], reverse=True)[:population_size // 2]
selected = [elite[i] for i in np.random.choice(len(elite), population_size // 2, replace=False)]
offspring = [mate(*pair) for pair in selected]
offspring += [mutate(ind, mutation_rate) for ind in offspring]
# 更新种群
population = offspring
return elite[0][0] # 返回最佳解
# 示例用法
best_solution = double_phase_ga(initialize_population(100, 10), 100, 0.7, 0.01, 1000)
```
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