generated from LufsX/Experiment-LogReg
105 lines
3.0 KiB
Python
105 lines
3.0 KiB
Python
import numpy as np
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import pandas as pd
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from sklearn.preprocessing import StandardScaler
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from sklearn.model_selection import train_test_split, GridSearchCV
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id = "202210423130"
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name = "董秋"
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def train_logreg(X, y, learning_rate=0.01, iterations=1000, lambda_reg=0.01):
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"""
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对率回归训练函数。
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Args:
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- X (numpy array): 特征数据。
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- y (numpy array): 标签数据。
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Returns:
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- numpy array: 训练得到的权重。
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"""
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m, n = X.shape
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weights = np.zeros(n)
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for i in range(iterations):
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z = np.dot(X, weights)
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predictions = 1 / (1 + np.exp(-z))
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gradient = np.dot(X.T, (predictions - y)) / m
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# L2正则化：将正则项添加到梯度上
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gradient += (lambda_reg / m) * weights
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# 更新权重
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weights -= learning_rate * gradient
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# 动态调整学习率
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learning_rate *= 0.95 # 每次迭代将学习率乘以0.99
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return weights
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def predict_logreg(inX, weights):
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"""
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对率回归预测函数。
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Args:
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- inX (numpy array): 输入待分类的样本。
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- weights (numpy array): 训练得到的权重。
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Returns:
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- int: 预测的分类标签。
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"""
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z = np.dot(inX, weights)
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prediction_prob = 1 / (1 + np.exp(-z))
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return 1 if prediction_prob >= 0.5 else 0
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def load_data(filepath):
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data = []
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labels = []
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with open(filepath, 'r') as f:
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for line in f:
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values = line.strip().replace('?', '0').split()
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try:
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values = [float(v) for v in values]
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if values[22] == 2 or values[22] == 3:
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labels.append(0)
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elif values[22] == 1:
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labels.append(1)
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else:
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continue
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values = [0 if np.isnan(v) else v for v in values]
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data.append(values[:2] + values[3:23])
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except ValueError:
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continue
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return np.array(data), np.array(labels)
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def preprocess_data(X):
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scaler = StandardScaler()
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return scaler.fit_transform(X)
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if __name__ == "__main__":
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# 加载数据集
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X, y = load_data("./data/horse-colic.data")
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X = preprocess_data(X)
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X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
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# 定义参数网格
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param_grid = {
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'learning_rate': [0.01, 0.05, 0.1],
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'iterations': [500, 1000, 2000],
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'lambda_reg': [0.01, 0.1, 1]
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}
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# 网格搜索中定义的参数
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best_params = {'learning_rate': 0.1, 'iterations': 1000, 'lambda_reg': 0.01}
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# 使用最佳参数重新训练模型
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weights = train_logreg(X_train, y_train,
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learning_rate=best_params['learning_rate'],
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iterations=best_params['iterations'],
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lambda_reg=best_params['lambda_reg'])
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# 测试单个数据
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y_pred = predict_logreg(X_test[11], weights)
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print(f"预测结果: {y_pred}, 实际结果: {y_test[11]}")
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