给出SADE的python实现
时间: 2023-07-07 15:45:19 浏览: 39
SADE算法是DE算法的一种改进,通过策略自适应技术来提高DE算法的性能。下面是一个简单的SADE算法的Python实现:
```python
import random
import numpy as np
def sade(popsize, bounds, maxiter, func, strategy=1, p=0.5, F=None):
# 初始化参数
num_params = len(bounds)
pop = np.random.rand(popsize, num_params)
min_b, max_b = np.asarray(bounds).T
diff = np.fabs(min_b - max_b)
pop_denorm = min_b + pop * diff
fitness = np.asarray([func(ind) for ind in pop_denorm])
best_idx = np.argmin(fitness)
best = pop_denorm[best_idx]
# 迭代优化
for i in range(maxiter):
# 选择两个不同的个体作为parent
p1, p2 = random.sample(range(popsize), 2)
# 选择三个不同的个体作为mutation vectors
idxs = [idx for idx in range(popsize) if idx not in (p1, p2)]
a, b, c = pop[np.random.choice(idxs, 3, replace=False)]
if strategy == 1:
# DE/rand/1/bin策略
mutant = a + F * (b - c)
elif strategy == 2:
# DE/current-to-best/1/bin策略
mutant = pop[p1] + F * (best - pop[p1]) + F * (b - c)
else:
# DE/rand-to-best/1/bin策略
mutant = a + F * (best - a) + F * (b - c)
# 随机选择交叉点
cross_points = np.random.rand(num_params) < p
if not np.any(cross_points):
cross_points[np.random.randint(0, num_params)] = True
# 生成trial vector
trial = np.where(cross_points, mutant, pop[p1])
trial_denorm = min_b + trial * diff
f = func(trial_denorm)
# 选择个体替换
if f < fitness[p1]:
pop[p1] = trial
fitness[p1] = f
if f < fitness[best_idx]:
best_idx = p1
best = trial_denorm
# 更新F
if strategy == 1:
F = np.clip(F + 0.001, 0.0, 1.0)
elif strategy == 2:
F = np.clip(F * 0.95, 0.0, 1.0)
else:
F = np.clip(F + 0.001, 0.0, 1.0)
if random.random() < 0.1:
strategy = random.choice([1, 2, 3])
yield best, fitness[best_idx]
# 测试函数
def sphere(x):
return sum(x**2)
# 运行SADE算法
popsize = 10
bounds = [(-5, 5)] * 10
maxiter = 1000
strategy = 1
p = 0.5
F = 0.5
for best, fitness in sade(popsize, bounds, maxiter, sphere, strategy, p, F):
print("best: ", best, " fitness: ", fitness)
```
请注意,上面的代码只是一个简单的SADE算法示例,可能不是完全符合论文中描述的算法。如果你需要更多的参考资料,请参阅相关的文献或者开源科学计算库中的实现。