diff --git a/function.py b/function.py index 2959942..0d6661c 100644 --- a/function.py +++ b/function.py @@ -1,140 +1,57 @@ -import os import numpy as np -""" -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。 - -注意事项: -- 在 function.py 中实现对率回归算法。 -- 可以自行导入其他库,需要在 requirements.txt 添加依赖,若未在 requirements.txt 中添加使用到的依赖,则无法自动评测,成绩为零。 -- 自动评测脚本仅会加载 train_logreg、predict_logreg 和 load_data 函数,请勿修改函数名。 - -测评环境: -- CPU: Intel Xeon(R) CPU E3-1231 v3 @ 3.40GHz -- OS: Ubuntu 22.04.4 LTS -- Python: 3.10.12 -- numpy: 2.1.1 -""" - -""" -请在这里填写学号和姓名,不填写即成绩无效。 -""" id = "202210423105" name = "魏明帅" -# 这里写自己的代码实现 -import numpy as np -from sklearn.preprocessing import MinMaxScaler -from sklearn.model_selection import train_test_split - - -def sigmoid(z): - return 1.0 / (1 + np.exp(-z)) - - -def compute_gradient(X_batch, y_batch, weights, lambda_reg): - 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 - - -def train_logreg(X, y, learning_rate=0.001, iterations=10000, batch_size=64, lambda_reg=0.1): +def train_logreg(X, y, learning_rate=0.01, iterations=1000): m, n = X.shape - weights = np.random.randn(n) * np.sqrt(2. / n) # He初始化 - best_weights = weights.copy() - best_accuracy = 0 - + # 添加偏置项 + X = np.c_[np.ones((m, 1)), X] + weights = np.zeros(n + 1) + for _ 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 - - # 计算训练集准确率 - train_accuracy = accuracy(X, y, weights) - if train_accuracy > best_accuracy: - best_accuracy = train_accuracy - best_weights = weights.copy() - - # 动态调整学习率 - if _ % 100 == 0 and train_accuracy > 0.95: # 达到高准确率时减小学习率 - learning_rate *= 0.9 - - return best_weights - - -def predict_logreg(X, weights): - z = np.dot(X, weights) - h = sigmoid(z) - return np.where(h >= 0.5, 1, 0) + for i in range(m): + x_i = X[i] + y_i = y[i] + z = np.dot(x_i, weights) + h = 1 / (1 + np.exp(-z)) + error = y_i - h + weights += learning_rate * error * x_i + + return weights +def predict_logreg(inX, weights): + z = np.dot(inX, weights) + h = 1 / (1 + np.exp(-z)) + return 1 if h >= 0.5 else 0 def load_data(filepath): - data, labels = [], [] + X = [] + y = [] with open(filepath, 'r') as f: for line in f: - line = line.strip().split() - if len(line) >= 1 and line[-1].isdigit(): - line_data = [0 if x == '?' else float(x) for x in line[:-1]] - data.append(line_data) - labels.append(int(line[-1])) - - data = np.array(data) - labels = np.array(labels) - + values = line.strip().split() + # 跳过包含 '?' 的行 + if '?' in values: + continue + # 将标签和特征转换为浮点数 + y.append(float(values[-1])) + X.append([float(x) for x in values[:-1]]) - num_features = data.shape[1] - + X_array = np.array(X) + y_array = np.array(y).reshape(-1, 1) - indices_to_delete = [2] - if num_features > 24: - indices_to_delete += list(range(24, 27)) - + # 特征缩放,处理标准差为零的特征 + means = np.mean(X_array, axis=0) + stds = np.std(X_array, axis=0) + X_scaled = (X_array - means) / np.where(stds == 0, 1, stds) - data = np.delete(data, indices_to_delete, axis=1) - - - target_variable = np.where((labels == 2) | (labels == 3), 0, 1) - - return data, target_variable - - -def accuracy(X, y, weights): - predictions = predict_logreg(X, weights) - return np.mean(predictions == y) - + return X_scaled, y_array if __name__ == "__main__": - # 加载数据 - X, y = load_data("./data/horse-colic.data") - - # 拆分训练集和验证集 - X_train, X_val, y_train, y_val = train_test_split(X, y, test_size=0.2, random_state=42) - - # 数据归一化 - scaler = MinMaxScaler() - X_train = scaler.fit_transform(X_train) - X_val = scaler.transform(X_val) - - # 训练模型 - final_weights = train_logreg(X_train, y_train, learning_rate=0.01, iterations=5000, batch_size=64, lambda_reg=0.1) - - # 验证模型 - val_accuracy = accuracy(X_val, y_val, final_weights) - print(f"验证集的准确率: {val_accuracy:.4f}") - - # 加载测试集 + X_train, y_train = load_data("./data/horse-colic.data") X_test, y_test = load_data("./data/horse-colic.test") - X_test = scaler.transform(X_test) - # 测试模型 - final_test_accuracy = accuracy(X_test, y_test, final_weights) - print(f"最终测试集的准确率: {final_test_accuracy:.4f}") \ No newline at end of file + weights = train_logreg(X_train, y_train, learning_rate=0.01, iterations=1000) + y_pred = predict_logreg(X_test[11], weights) + print(f"预测结果: {y_pred}, 实际结果: {y_test[11]}") \ No newline at end of file