diff --git a/function.py b/function.py index f189af5..5466123 100644 --- a/function.py +++ b/function.py @@ -1,111 +1,65 @@ -import numpy as np +import numpy as np -""" -请在这里填写学号和姓名,不填写即成绩无效。 -""" -id = "202210423224" -name = "吴杨洋" +# 学号和姓名 +id = "202210423224" +name = "吴杨洋" +def sigmoid(z): + return 1 / (1 + np.exp(-z)) -def sigmoid(z): - """ - Sigmoid 激活函数。 - """ - return 1 / (1 + np.exp(-z)) +def train_logreg(X, y, num_iter=1000, learning_rate=0.01, lambda_reg=0.01): + m, n = X.shape + weights = np.zeros(n) + + for _ in range(num_iter): + z = np.dot(X, weights) + h = sigmoid(z) + error = y - h + + # 添加正则化项 + gradient = np.dot(X.T, error) / m + lambda_reg * weights / m + weights += learning_rate * gradient + + return weights +def predict_logreg(X, weights): + probabilities = sigmoid(np.dot(X, weights)) + return (probabilities >= 0.5).astype(int) -def train_logreg(X, y, numIter=1000, learning_rate=0.01, lambda_reg=0.01): - m, n = X.shape - weights = np.zeros(n) - for j in range(numIter): - for i in range(m): - z = np.dot(X[i], weights) - h = sigmoid(z) - error = y[i] - h - gradient = X[i] * error - reg_term = lambda_reg * weights - gradient += reg_term - weights += learning_rate * gradient - return weights +def load_data(filepath): + data = np.genfromtxt(filepath, delimiter=',', dtype=str, filling_values=np.nan) + # 处理缺失值,转换数据类型 + data = np.where(data == '?', np.nan, data).astype(np.float) + data = data[~np.isnan(data).any(axis=1)] # 删除含有NaN的行 + # 特征与标签分离 + X = np.delete(data, [22, 24, 25, 26, -1], axis=1) # 删除不需要的列 + y = np.array([1 if row[22] in ['2', '3'] else 0 for row in data]) # 生成标签 + X = np.insert(X, 0, 1, axis=1) # 添加偏置项 -def predict_logreg(inX, weights): - """ - 对率回归预测函数。 + return X, y - Args: - - inX (numpy array): 输入待分类的样本。 - - weights (numpy array): 训练得到的权重。 +def standardize(X): + mean = X.mean(axis=0) + std = X.std(axis=0) + return (X - mean) / std, mean, std - Returns: - - int: 预测的分类标签。 - """ - z = np.dot(inX, weights) - prob = sigmoid(z) - return 1 if prob >= 0.5 else 0 +def main(): + # 加载训练集和测试集 + X_train, y_train = load_data("./data/horse-colic.data") + X_test, y_test = load_data("./data/horse-colic.test") + # 数据标准化 + X_train, mean, std = standardize(X_train) + X_test = (X_test - mean) / std -def load_data(filepath): - """ - 从文件中加载数据,若不自行正确实现,则无法通过评测,不记录成绩。 + # 训练对率回归模型 + weights = train_logreg(X_train, y_train, num_iter=1000, learning_rate=0.01, lambda_reg=0.1) - Args: - - filepath (str): 数据文件路径。 + # 测试模型 + y_pred_test = predict_logreg(X_test, weights) + accuracy_test = np.mean(y_pred_test == y_test) + print(f"Test Accuracy: {accuracy_test:.2f}") - Returns: - - X (np.array): 特征数据。 - - y (np.array): 标签数据。 - """ - file = open(filepath) - fr = file.readlines() - data_list = [] - y = [] - for data in fr: - data = data.strip() - data = data.split(' ') - data_25 = data[24] - y.append(data[22]) - del data[-1] - del data[26] - del data[25] - del data[24] - del data[22] - del data[2] - for i in data_25: - data.append(i) - data = [0 if data_elem == '?' else float(data_elem) for data_elem in data] - data_list.append(data) - data_number = len(y) - y_train = np.array([1 if y[j] == '2' or y[j] == '3' else 0 for j in range(data_number)]) - X = np.array(data_list) - X_train = np.insert(X, 0, 1, axis=1) # 添加偏置项 - return X_train, y_train - - -def standardize(X): - mean = X.mean(axis=0) - std = X.std(axis=0) - return (X - mean) / std, mean, std - - -def main(): - # 加载训练集 - X_train, y_train = load_data("./data/horse-colic.data") - # 加载测试集 - X_test, y_test = load_data("./data/horse-colic.test") - - # 标准化特征数据 - X_train, mean, std = standardize(X_train) - X_test = (X_test - mean) / std - - # 训练对率回归模型 - weights = train_logreg(X_train, y_train, numIter=1000, learning_rate=0.01, lambda_reg=0.1) - - # 测试单个数据 - y_pred_test = [predict_logreg(x, weights) for x in X_test] - accuracy_test = np.mean(y_pred_test == y_test) - print(f"Test Accuracy: {accuracy_test:.2f}") - - -if __name__ == "__main__": +if __name__ == "__main__": main() \ No newline at end of file