diff --git a/function.py b/function.py index 1fb7faf..df7f270 100644 --- a/function.py +++ b/function.py @@ -1,8 +1,5 @@ -# function.py +import os import numpy as np -import pandas as pd -from sklearn.preprocessing import StandardScaler -from sklearn.model_selection import train_test_split, KFold """ 实验说明: @@ -24,111 +21,84 @@ from sklearn.model_selection import train_test_split, KFold """ 请在这里填写学号和姓名,不填写即成绩无效。 """ -id = "202210423209" -name = "万子玉" +id = "202210218225" +name = "周水源" + # 这里写自己的代码实现 +import numpy as np +from sklearn.metrics import accuracy_score + +# 定义sigmoid函数 def sigmoid(z): - return 1.0 / (1 + np.exp(-z)) + return 1 / (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): +# 训练逻辑回归模型 +def train_logreg(X, y, learning_rate, 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 - + weights = np.zeros(n) + bias = 0 for _ in range(iterations): - indices = np.random.permutation(m) - X_shuffled = X[indices] - y_shuffled = y[indices] + z = np.dot(X, weights) + bias + h = sigmoid(z) + dw = (1/m) * np.dot(X.T, (h - y)) + db = (1/m) * np.sum(h - y) + weights -= learning_rate * dw + bias -= learning_rate * db + return weights, bias - 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) +# 使用逻辑回归模型进行预测 +def predict_logreg(inX, weights, bias): + z = np.dot(inX, weights) + bias h = sigmoid(z) - return np.where(h >= 0.5, 1, 0) + return 1 if h >= 0.5 else 0 +# 加载数据 def load_data(filepath): - data, labels = [], [] - 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 = [] + with open(filepath, 'r') as file: + for line in file: + cleaned_line = line.strip().replace('?', '0') + values = [float(x) for x in cleaned_line.split()] + if values[22] in [2, 3]: + values[22] = 0 + new_values = values[:2] + values[3:23] + data.append(new_values) data = np.array(data) - labels = np.array(labels) + X = data[:, :-1] + y = data[:, -1] + return X, y - # 检查特征数量 - num_features = data.shape[1] +# 寻找最佳学习率 +def find_best_learning_rate(X, y, learning_rates, iterations=1000): + best_accuracy = 0 + best_learning_rate = None + best_weights = None + best_bias = None + for rate in learning_rates: + weights, bias = train_logreg(X, y, rate, iterations) + y_pred = np.array([predict_logreg(x, weights, bias) for x in X]) + accuracy = accuracy_score(y, y_pred) + if accuracy > best_accuracy: + best_accuracy = accuracy + best_learning_rate = rate + best_weights = weights + best_bias = bias + return best_learning_rate, best_accuracy, best_weights, best_bias - # 特征选择:去掉特征3和特征24~28,确保索引有效 - indices_to_delete = [2] # 特征3 - if num_features > 24: # 确保特征数量足够 - indices_to_delete += list(range(24, 27)) # 特征24到27 - - # 删除特征 - data = np.delete(data, indices_to_delete, axis=1) - - # 将标签二分类化,特征23取值2和3合并为0,其余为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) - -# 其余代码保持不变 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 + + # 定义要尝试的学习率列表 + learning_rates = np.linspace(0.001, 0.1, 50) + + # 寻找最佳学习率 + best_learning_rate, best_accuracy, best_weights, best_bias = find_best_learning_rate(X_train, y_train, learning_rates) + + print(f"最佳学习率: {best_learning_rate}") + print(f"最佳准确率: {best_accuracy}") + + # 使用最佳权重和偏置进行预测 + y_pred = predict_logreg(X_test[11], best_weights, best_bias) + print(f"预测结果: {y_pred}, 实际结果: {y_test[11]}") \ No newline at end of file