帮我在下面的代码中添加高斯优化,原代码如下:import numpy as np from sklearn.svm import OneClassSVM from scipy.optimize import minimize def fitness_function(x): """ 定义适应度函数,即使用当前参数下的模型进行计算得到的损失值 """ gamma, nu = x clf = OneClassSVM(kernel='rbf', gamma=gamma, nu=nu) clf.fit(train_data) y_pred = clf.predict(test_data) # 计算错误的预测数量 error_count = len([i for i in y_pred if i != 1]) # 将错误数量作为损失值进行优化 return error_count def genetic_algorithm(x0, bounds): """ 定义遗传算法优化函数 """ population_size = 20 # 种群大小 mutation_rate = 0.1 # 变异率 num_generations = 50 # 迭代次数 num_parents = 2 # 选择的父代数量 num_elites = 1 # 精英数量 num_genes = x0.shape[0] # 参数数量 # 随机初始化种群 population = np.random.uniform(bounds[:, 0], bounds[:, 1], size=(population_size, num_genes)) for gen in range(num_generations): # 选择父代 fitness = np.array([fitness_function(x) for x in population]) parents_idx = np.argsort(fitness)[:num_parents] parents = population[parents_idx] # 交叉 children = np.zeros_like(parents) for i in range(num_parents): j = (i + 1) % num_parents mask = np.random.uniform(size=num_genes) < 0.5 children[i, mask] = parents[i, mask] children[i, ~mask] = parents[j, ~mask] # 变异 mask = np.random.uniform(size=children.shape) < mutation_rate children[mask] = np.random.uniform(bounds[:, 0], bounds[:, 1], size=np.sum(mask)) # 合并种群 population = np.vstack([parents, children]) # 选择新种群 fitness = np.array([fitness_function(x) for x in population]) elites_idx = np.argsort(fitness)[:num_elites] elites = population[elites_idx] # 输出结果 best_fitness = fitness[elites_idx[0]] print(f"Gen {gen+1}, best fitness: {best_fitness}") return elites[0] # 初始化参数 gamma0, nu0 = 0.1, 0.5 x0 = np.array([gamma0, nu0]) bounds = np.array([[0.01, 1], [0.01, 1]]) # 调用遗传算法优化 best_param = genetic_algorithm(x0, bounds) # 在最佳参数下训练模型,并在测试集上进行测试 clf = OneClassSVM(kernel='rbf', gamma=best_param[0], nu=best_param[1]) clf.fit(train_data) y_pred = clf.predict(test_data) # 计算错误的预测数量 error_count = len([i for i in y_pred if i != 1]) print(f"Best fitness: {error_count}, best parameters: gamma={best_param[0]}, nu={best_param[1]}")
时间: 2023-06-07 07:07:07 浏览: 99
您好,为了在下面的代码中添加高斯优化,您需要使用scipy模块中的optimize包,并使用minimize函数进行优化。具体修改如下:
import numpy as np
from sklearn.svm import OneClassSVM
from scipy.optimize import minimize
def fitness_function(x):
"""
定义适应度函数,即使用当前参数下的模型进行计算得到的损失值
"""
gamma, nu = x
clf = OneClassSVM(kernel='rbf', gamma=gamma, nu=nu)
clf.fit(train_data)
y_pred = clf.predict(test_data)
# 计算损失值
loss = np.sum(y_pred != test_label) / len(test_label)
return loss
# 定义初始参数值
gamma_init = 0.1
nu_init = 0.01
x_init = np.array([gamma_init, nu_init])
# 进行高斯优化
res = minimize(fitness_function, x_init, method='L-BFGS-B', bounds=((0, None), (0, 1)))
gamma_opt, nu_opt = res.x
# 使用优化后的参数值构建模型
clf_opt = OneClassSVM(kernel='rbf', gamma=gamma_opt, nu=nu_opt)
clf_opt.fit(train_data)
y_pred_opt = clf_opt.predict(test_data)
# 输出优化后的模型损失
loss_opt = np.sum(y_pred_opt != test_label) / len(test_label)
print('优化后模型的损失值:', loss_opt)
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