diff --git a/function.py b/function.py index f3b712d..5845098 100644 --- a/function.py +++ b/function.py @@ -1,89 +1,81 @@ -import numpy as np +import numpy as np -# 学号和姓名 -id = "202210423224" -name = "吴杨洋" +id = "202210423224" +name = "吴杨洋" -def sigmoid(z): - """ - Sigmoid 激活函数。 - """ - return 1 / (1 + np.exp(-z)) +def sigmoid(z): + """Sigmoid 激活函数,添加 clipping 防止溢出""" + z = np.clip(z, -500, 500) # 限制 z 的值范围 + 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) +def train_logreg(X, y, numIter=1000, learning_rate=0.01, lambda_reg=0.01, batch_size=64): + m, n = X.shape + weights = np.zeros(n) + for j in range(numIter): + indices = np.random.permutation(m) + X_shuffled = X[indices] + y_shuffled = y[indices] + for i in range(0, m, batch_size): + end = min(i + batch_size, m) + batch_X = X_shuffled[i:end] + batch_y = y_shuffled[i:end] + z = np.dot(batch_X, weights) + h = sigmoid(z) + error = batch_y - h + gradient = np.dot(batch_X.T, error) / len(batch_y) + reg_term = lambda_reg * weights + gradient += reg_term / len(batch_y) + weights -= learning_rate * gradient + return weights - for _ in range(num_iter): - z = np.dot(X, weights) - h = sigmoid(z) - error = y - h - - # 计算梯度并添加正则化项 - gradient = np.dot(X.T, error) / m + (lambda_reg / m) * weights - weights += learning_rate * gradient +def predict_logreg(inX, weights): + z = np.dot(inX, weights) + prob = sigmoid(z) + return 1 if prob >= 0.5 else 0 - return weights +def load_data(filepath): + 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 predict_logreg(X, weights): - """ - 对率回归预测函数。 - - Args: - - X (numpy array): 输入待分类的样本。 - - weights (numpy array): 训练得到的权重。 - - Returns: - - numpy array: 预测的分类标签。 - """ - probabilities = sigmoid(np.dot(X, weights)) - return (probabilities >= 0.5).astype(int) +def standardize(X): + mean = X.mean(axis=0) + std = X.std(axis=0) + return (X - mean) / std, mean, std -def load_data(filepath): - """ - 从文件中加载数据。 +def main(): + X_train, y_train = load_data("./data/horse-colic.data") + X_test, y_test = load_data("./data/horse-colic.test") - Args: - - filepath (str): 数据文件路径。 + X_train, mean, std = standardize(X_train) + X_test = (X_test - mean) / std - Returns: - - X (np.array): 特征数据。 - - y (np.array): 标签数据。 - """ - data = np.genfromtxt(filepath, delimiter=',', dtype=str, filling_values=np.nan) - - # 处理缺失值和类型转换 - data = np.where(data == '?', np.nan, data).astype(float) - data = data[~np.isnan(data).any(axis=1)] # 删除含有NaN的行 + weights = train_logreg(X_train, y_train, numIter=1000, learning_rate=0.01, lambda_reg=0.1, batch_size=64) - # 提取特征和标签 - 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 + 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}") - return X, y - -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 - - # 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) - - # 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}") - -if __name__ == "__main__": +if __name__ == "__main__": main() \ No newline at end of file