diff --git a/function.py b/function.py index 92c3b6f..f10c9f2 100644 --- a/function.py +++ b/function.py @@ -1,9 +1,10 @@ -# function.py import os import numpy as np import pandas as pd from sklearn.preprocessing import MinMaxScaler from sklearn.model_selection import train_test_split +from sklearn.impute import SimpleImputer + """ 实验说明: - 自行编写实现数据加载与预测病马死亡的对率回归算法。 @@ -17,14 +18,16 @@ from sklearn.model_selection import train_test_split - Python: 3.10.12 - numpy: 2.1.1 """ -# Sigmoid 函数 -def sigmoid(z): - return 1 / (1 + np.exp(-z)) +# Sigmoid 函数 +def sigmoid(z): + return 1 / (1 + np.exp(-z)) + """ 请在这里填写学号和姓名,不填写即成绩无效。 """ id = "202210423223" name = "李顺潮" + # 对率回归训练函数 def train_logreg(X, y, learning_rate=0.01, iterations=1000): X = np.hstack((np.ones((X.shape[0], 1)), X)) # 在特征前添加一列全为1的列 @@ -33,50 +36,56 @@ def train_logreg(X, y, learning_rate=0.01, iterations=1000): for _ in range(iterations): z = np.dot(X, weights) - predictions = 1 / (1 + np.exp(-z)) + predictions = sigmoid(z) # 使用sigmoid函数 gradient = np.dot(X.T, (predictions - y)) / m weights -= learning_rate * gradient return weights -# 对率回归预测函数 -# 对率回归预测函数,支持多类分类 +# 对率回归预测函数 def predict_logreg(inX, weights): inX = np.insert(inX, 0, 1) # 在特征前添加1作为偏置项 - prob = 1 / (1 + np.exp(-np.dot(inX, weights))) + prob = sigmoid(np.dot(inX, weights)) # 使用sigmoid函数 - if prob < 0.5: - return 0 - elif prob >= 0.5 and prob < 1.0: - return 1 - else: - return 2 # 确保返回3个类别中的一个 + return 1 if prob >= 0.5 else 0 -# 从文件中加载数据 + +# 从文件中加载数据 def load_data(filepath): data = pd.read_csv(filepath, header=None, na_values='?', delim_whitespace=True) - data.fillna(0, inplace=True) + + # 使用更合理的缺失值填充策略,例如用均值或中位数填充 + imputer = SimpleImputer(strategy='mean') # 使用均值填充 + data = pd.DataFrame(imputer.fit_transform(data)) + + X = data.iloc[:, :-1].to_numpy() # 特征 - y = data.iloc[:, -1].to_numpy() # 标签 - return X, y + y = data.iloc[:, -1].to_numpy().astype(int) # 标签,确保y是整数类型 + return X, y + # 准确率计算函数 def calculate_accuracy(X, y, weights): predictions = np.array([predict_logreg(x, weights) for x in X]) accuracy = np.mean(predictions == y) return accuracy -if __name__ == "__main__": - # 加载训练集和测试集 +if __name__ == "__main__": + # 加载训练集和测试集 X_train, y_train = load_data("E:\\Edge站内文件下载\\病马数据集\\horse-colic.data") - X_test, y_test = load_data( "E:\\Edge站内文件下载\\病马数据集\\horse-colic.test") - - # 训练对率回归模型 - weights = train_logreg(X_train, y_train, learning_rate=0.01, iterations=1000) - - # 测试单个数据 - y_pred = predict_logreg(X_test[11], weights) - print(f"预测结果: {y_pred}, 实际结果: {y_test[11]}") + X_test, y_test = load_data("E:\\Edge站内文件下载\\病马数据集\\horse-colic.test") + # 特征缩放 (可选,但建议尝试) + scaler = MinMaxScaler() + X_train = scaler.fit_transform(X_train) + X_test = scaler.transform(X_test) + + + # 训练对率回归模型 + weights = train_logreg(X_train, y_train, learning_rate=0.01, iterations=10000) #增加迭代次数 + + # 测试单个数据 + y_pred = predict_logreg(X_test[11], weights) + print(f"预测结果: {y_pred}, 实际结果: {y_test[11]}") # 计算并输出模型的准确率 accuracy = calculate_accuracy(X_test, y_test, weights)