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from datetime import datetime
import keras
from model_core import LeNet5Custom
import matplotlib.pyplot as plt
# 打印模型框架基本信息
print(keras.__version__)
def load_and_preprocess_data():
# 加载MNIST数据集
(train_images, train_labels), (test_images, test_labels) = keras.datasets.mnist.load_data()
# 反转像素值255 - x
train_images = 255 - train_images
test_images = 255 - test_images
# 归一化像素值到 [0, 1] 区间
train_images = train_images.astype("float32") / 255
test_images = test_images.astype("float32") / 255
# 由于 MNIST 的图像是灰度图像,需要增加一个颜色通道
train_images = train_images.reshape(-1, 28, 28, 1)
test_images = test_images.reshape(-1, 28, 28, 1)
# 对标签进行分类编码
train_labels = keras.utils.to_categorical(train_labels, 10)
test_labels = keras.utils.to_categorical(test_labels, 10)
return train_images, train_labels, test_images, test_labels
def lr_schedule(epoch):
lr = 1e-3
if epoch > 15:
lr *= 0.1
elif epoch > 55:
lr *= 0.01
return lr
class TrainingHistory(keras.callbacks.Callback):
def on_train_begin(self, logs={}):
self.history = {'loss': [], 'accuracy': [], 'val_loss': [], 'val_accuracy': []}
def on_epoch_end(self, epoch, logs={}):
self.history['loss'].append(logs.get('loss'))
self.history['accuracy'].append(logs.get('accuracy'))
self.history['val_loss'].append(logs.get('val_loss'))
self.history['val_accuracy'].append(logs.get('val_accuracy'))
def train_model_dp(train_images, train_labels, test_images, test_labels, dropout_rates, epochs):
lr_scheduler = keras.callbacks.LearningRateScheduler(lr_schedule)
early_stopping = keras.callbacks.EarlyStopping(monitor='val_loss',
patience=3,
restore_best_weights=True)
history_callback = TrainingHistory()
best_accuracy = 0.0
best_dropout_rate = None
best_model = None
for dropout_rate in dropout_rates:
print(f"Training model with dropout rate: {dropout_rate}")
model = LeNet5Custom(dropout_rate)
model = model.compile_model()
model.summary()
model.fit(train_images,
train_labels,
epochs=epochs,
batch_size=256,
validation_data=(test_images, test_labels),
callbacks=[lr_scheduler, early_stopping, history_callback])
# 评估模型
test_loss, test_acc = model.evaluate(test_images, test_labels)
print(f'Test Accuracy with dropout rate {dropout_rate}: {test_acc:.4f} with loss {test_loss:.4f}')
if test_acc > best_accuracy:
best_accuracy = test_acc
best_dropout_rate = dropout_rate
best_model = model
return best_model, best_dropout_rate, best_accuracy, history_callback.history
def plot_history(history):
epochs = range(1, len(history['loss']) + 1)
plt.figure(figsize=(12, 10))
plt.subplot(2, 1, 1)
plt.plot(epochs, history['loss'], label='Training Loss')
plt.plot(epochs, history['val_loss'], label='Validation Loss')
plt.title('Training and Validation Loss')
plt.xlabel('Epochs')
plt.ylabel('Loss')
plt.legend()
plt.subplot(2, 1, 2)
plt.plot(epochs, history['accuracy'], label='Training Accuracy')
plt.plot(epochs, history['val_accuracy'], label='Validation Accuracy')
plt.title('Training and Validation Accuracy')
plt.xlabel('Epochs')
plt.ylabel('Accuracy')
plt.legend()
plt.tight_layout()
plt.show()
def save_model(model, accuracy):
timestamp = datetime.now().strftime("%Y%m%d_%H%M%S") # 获取当前时间戳并格式化为字符串
filepath = f'./model/lenet5_model_best_{timestamp}.h5'
model.save(filepath=filepath)
print(f"Best model weights saved to {filepath} with test accuracy: {accuracy:.4f}")
if __name__ == "__main__":
keras.backend.clear_session()
train_images, train_labels, test_images, test_labels = load_and_preprocess_data()
dropout_rates = [0.3] # 0.3 is the best of [0.1, 0.2, 0.3, 0.4, 0.5]
epochs = 100
best_model, best_dropout_rate, best_accuracy, history = train_model_dp(train_images,
train_labels,
test_images,
test_labels,
dropout_rates,
epochs)
print(f'Best dropout rate: {best_dropout_rate} with test accuracy: {best_accuracy:.4f}')
save_model(best_model, best_accuracy)
plot_history(history)
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