用python3语言写遗传算法优化lightgbm参数的代码
时间: 2023-02-27 13:58:52 浏览: 166
下面是一个示例代码,它使用遗传算法来优化LightGBM的参数:
```python
import numpy as np
import lightgbm as lgb
from sklearn.model_selection import cross_val_score
from sklearn.datasets import load_breast_cancer
from sklearn.model_selection import train_test_split
import random
# 设置遗传算法的参数
population_size = 100
generations = 20
mutation_prob = 0.1
# 定义遗传算法中用到的参数
param_grid = {
'boosting_type': ['gbdt', 'dart'],
'num_leaves': list(range(20, 150)),
'learning_rate': list(np.logspace(np.log10(0.005), np.log10(0.5), base = 10, num = 1000)),
'subsample_for_bin': list(range(20000, 300000, 20000)),
'min_child_samples': list(range(20, 500, 5)),
'reg_alpha': list(np.linspace(0, 1)),
'reg_lambda': list(np.linspace(0, 1)),
'colsample_bytree': list(np.linspace(0.6, 1, 10)),
'subsample': list(np.linspace(0.5, 1, 100)),
'is_unbalance': [True, False]
}
# 加载数据集
X, y = load_breast_cancer(return_X_y=True)
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2)
# 遗传算法
def genetic_algorithm(population_size, generations, mutation_prob):
population = []
for i in range(population_size):
individual = {key: random.choice(value) for key, value in param_grid.items()}
population.append(individual)
for generation in range(generations):
print(f"Generation {generation}")
scores = []
for individual in population:
model = lgb.LGBMClassifier(boosting_type=individual['boosting_type'],
num_leaves=individual['num_leaves'],
learning_rate=individual['learning_rate'],
subsample_for_bin=individual['subsample_for_bin'],
min_child_samples=individual['min_child_samples'],
reg_alpha=individual['reg_alpha'],
reg_lambda=individual['reg_lambda'],
colsample_bytree=individual['colsample_bytree'],
subsample=individual['subsample'],
is_unbalance=individual['is_unbalance'])
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