diff --git a/function.py b/function.py index 5db80be..ffff354 100644 --- a/function.py +++ b/function.py @@ -26,54 +26,107 @@ import numpy as np id = "202210423113" name = "杨文强" -import os -from sklearn.preprocessing import StandardScaler -from sklearn.model_selection import train_test_split +def train_logreg(X, y, numIter=1000, learning_rate=0.06, batch_size=128, lambda_reg=0.01): + """ + 对率回归训练函数,加入L2正则化。 -def sigmoid(z): - """计算sigmoid函数""" - return 1.0 / (1 + np.exp(-z)) + Args: + - X (numpy array): 特征数据。 + - y (numpy array): 标签数据。 + - numIter (int): 迭代次数。默认为1000。 + - learning_rate (float): 学习率。默认为0.06。 + - batch_size (int): 批量大小。默认为128。 + - lambda_reg (float): L2正则化参数。默认为0.01。 -def compute_gradient(X_batch, y_batch, weights, lambda_reg): - """计算梯度,包含L2正则化""" - z = np.dot(X_batch, weights) - h = sigmoid(z) - gradient = np.dot(X_batch.T, (h - y_batch)) / len(y_batch) - gradient += (lambda_reg / len(y_batch)) * weights # L2正则化 - return gradient + Returns: + - numpy array: 训练得到的权重。 + """ + m, n = X.shape # m: 样本数, n: 特征数 + weights = np.zeros(n) # 参数初始化 -def train_logreg(X, y, learning_rate=0.001, iterations=10000, batch_size=64, lambda_reg=0.1): - """逻辑回归训练函数。""" - m, n = X.shape - weights = np.random.randn(n) * np.sqrt(2. / n) # He初始化 - print("开始训练逻辑回归模型") - - for i in range(iterations): - indices = np.random.permutation(m) - X_shuffled = X[indices] - y_shuffled = y[indices] - - for j in range(0, m, batch_size): - X_batch = X_shuffled[j:j + batch_size] - y_batch = y_shuffled[j:j + batch_size] - gradient = compute_gradient(X_batch, y_batch, weights, lambda_reg) - weights -= learning_rate * gradient + for j in range(numIter): + # 随机打乱样本顺序 + dataIndex = np.random.permutation(m) + for i in range(0, m, batch_size): + end = min(i + batch_size, m) + # 批量梯度下降 + batch_X = X[dataIndex[i:end]] + batch_y = y[dataIndex[i:end]] - if i % 1000 == 0: # 每1000次迭代打印一次信息 - print(f"迭代 {i}: 当前权重形状: {weights.shape}") + # 计算梯度 + z = np.dot(batch_X, weights) + h = 1 / (1 + np.exp(-z)) # 计算h + error = batch_y - h # 计算误差 + gradient = np.dot(batch_X.T, error) / len(batch_y) # 计算梯度 + # 添加L2正则化 + reg_term = 2 * lambda_reg * weights + gradient += reg_term / len(batch_y) + weights += learning_rate * gradient # 更新权重 return weights -def predict_logreg(inX, weights): - """逻辑回归预测函数。""" - z = np.dot(inX, weights) - h = sigmoid(z) - return 1 if h >= 0.5 else 0 +def predict_logreg(inX, weights): + """ + 对率回归预测函数。 + + Args: + - inX (numpy array): 输入待分类的样本。 + - weights (numpy array): 训练得到的权重。 + + Returns: + - int: 预测的分类标签。 + """ + z = np.dot(inX, weights) # 线性组合 + prob = 1 / (1 + np.exp(-z)) # 计算概率 + return 1 if prob >= 0.5 else 0 # 返回分类标签 + + + +# 这里也写自己的代码实现 +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**。 + + Args: + - directory (str): 数据文件路径。 + + Returns: + - np.array: 特征数据。 + - 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) + return X_train, y_train + + if __name__ == "__main__": + ''' # 以下代码可用于测试,可自行随意修改 # 加载训练集 X_train, y_train = load_data("./data/horse-colic.data") @@ -86,4 +139,17 @@ if __name__ == "__main__": # 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]}") + print(f"预测结果: {y_pred}, 实际结果: {y_test[11]}")''' + X_train, y_train = load_data("./data/horse-colic.data") + X_test, y_test = load_data("./data/horse-colic.test") + weights = train_logreg(X_train, y_train, numIter=1000, learning_rate=0.01,lambda_reg=0.2) + error=0 + for i in range(len(y_test)): + y_pred = predict_logreg(X_test[i], weights) + if y_pred != y_test[i]: + error+=1 + print(f"预测结果: {y_pred}, 实际结果: {y_test[i]}") + print((len(y_test)-error)/len(y_test)) + + +