编写pytorch代码,定义LSTMAttention模型,定义FA_CPSO优化算法,初始化混沌粒子群算法的位置、速度、种群规模等参数,利用混沌粒子群算法更新粒子群的速度和位置,在参数达到最优时引入萤火虫随机扰动,更新粒子群的参数,直到得到最优参数
时间: 2023-07-24 17:39:49 浏览: 57
好的,我会帮您实现这个模型和优化算法。下面是代码:
```python
import torch
import torch.nn as nn
import torch.nn.functional as F
import numpy as np
# 定义目标函数,这里使用交叉熵损失
def objective_function(model, data, target):
output = model(data)
loss = F.cross_entropy(output, target)
return loss
# 定义LSTMAttention模型
class LSTMAttention(nn.Module):
def __init__(self, input_size, hidden_size, num_classes):
super(LSTMAttention, self).__init__()
self.hidden_size = hidden_size
self.lstm = nn.LSTM(input_size, hidden_size, batch_first=True)
self.fc = nn.Linear(hidden_size, num_classes)
self.attention = nn.Linear(hidden_size, 1, bias=False)
def forward(self, x):
lstm_out, _ = self.lstm(x)
attention_weights = F.softmax(self.attention(lstm_out), dim=1)
attention_applied = torch.bmm(attention_weights.transpose(1, 2), lstm_out)
output = self.fc(attention_applied.squeeze(1))
return output
# 定义混沌序列生成函数
def chaotic_sequence(a, b, c, d, seed, length):
x = np.zeros(length)
x[0] = seed
for i in range(1, length):
x[i] = d * x[i - 1] + a * np.sin(b * x[i - 1]) + c
return x
# 定义萤火虫算法
def firefly_algorithm(pop_size, max_iter, dim, alpha, beta, gamma, lb, ub, obj_func):
# 初始化种群
pop = torch.FloatTensor(pop_size, dim).uniform_(lb, ub)
for i in range(max_iter):
# 计算种群适应度
fitness = obj_func(pop)
# 更新萤火虫位置
for j in range(pop_size):
for k in range(pop_size):
if fitness[j] < fitness[k]:
r = torch.norm(pop[j] - pop[k])
pop[j] += beta * torch.exp(-gamma * r ** 2.0) * (pop[k] - pop[j]) + alpha * torch.FloatTensor(dim).normal_(0, 1)
# 限制位置范围
pop = torch.clamp(pop, lb, ub)
# 返回最优解和最优适应度
best_fitness, best_idx = torch.min(obj_func(pop), 0)
best_solution = pop[best_idx]
return best_solution, best_fitness
# 定义FA_CPSO算法
def fa_cpso(pop_size, max_iter, dim, a, b, c, d, alpha, beta, gamma, lb, ub, obj_func):
# 初始化粒子群位置和速度
pos = torch.FloatTensor(pop_size, dim).uniform_(lb, ub)
vel = torch.FloatTensor(pop_size, dim).uniform_(lb, ub) - pos
# 初始化个体最优位置和适应度
pbest_pos = pos.clone()
pbest_fitness = obj_func(pbest_pos)
# 初始化全局最优位置和适应度
gbest_fitness, gbest_idx = torch.min(pbest_fitness, 0)
gbest_pos = pbest_pos[gbest_idx]
# 开始迭代
for i in range(max_iter):
# 生成混沌序列
chaos_seq = chaotic_sequence(a, b, c, d, i, pop_size)
# 更新粒子群速度和位置
vel = vel + chaos_seq.reshape(-1, 1) * (pbest_pos - pos) + chaos_seq.reshape(-1, 1) * (gbest_pos - pos)
pos = pos + vel
# 限制位置范围
pos = torch.clamp(pos, lb, ub)
# 更新个体最优位置和全局最优位置
fitness = obj_func(pos)
update_idx = fitness < pbest_fitness
pbest_pos[update_idx] = pos[update_idx]
pbest_fitness[update_idx] = fitness[update_idx]
if torch.min(pbest_fitness) < gbest_fitness:
gbest_fitness, gbest_idx = torch.min(pbest_fitness, 0)
gbest_pos = pbest_pos[gbest_idx]
# 引入萤火虫随机扰动
if i % 10 == 0:
best_solution, best_fitness = firefly_algorithm(pop_size, 10, dim, alpha, beta, gamma, lb, ub, obj_func)
update_idx = best_fitness < pbest_fitness
pbest_pos[update_idx] = best_solution
pbest_fitness[update_idx] = best_fitness
if torch.min(pbest_fitness) < gbest_fitness:
gbest_fitness, gbest_idx = torch.min(pbest_fitness, 0)
gbest_pos = pbest_pos[gbest_idx]
# 返回最优解和最优适应度
return gbest_pos, gbest_fitness
```
上述代码中,我们定义了目标函数,使用交叉熵损失函数。然后定义了LSTMAttention模型,该模型可以对输入进行处理,并输出分类结果。接着定义了混沌序列生成函数和萤火虫算法,以及结合两者的FA_CPSO算法。在FA_CPSO算法中,我们初始化粒子群的位置和速度,利用混沌序列更新粒子群的位置和速度,并引入萤火虫随机扰动更新粒子群的参数。最后得到最优解和最优适应度。
需要注意的是,上述代码中的参数需要根据具体问题进行调整,以达到更好的优化效果。