TensorFlow2.0教程4：keras模型保存和序列化
1.保持序列模型和函数模型
# 构建一个简单的模型并训练
from __future__ import absolute_import, division, print_function
import tensorflow as tf
tf.keras.backend.clear_session()
from tensorflow import keras
from tensorflow.keras import layers
inputs = keras.Input(shape=(784,), name='digits')
x = layers.Dense(64, activation='relu', name='dense_1')(inputs)
x = layers.Dense(64, activation='relu', name='dense_2')(x)
outputs = layers.Dense(10, activation='softmax', name='predictions')(x)
model = keras.Model(inputs=inputs, outputs=outputs, name='3_layer_mlp')
model.summary()
(x_train, y_train), (x_test, y_test) = keras.datasets.mnist.load_data()
x_train = x_train.reshape(60000, 784).astype('float32') / 255
x_test = x_test.reshape(10000, 784).astype('float32') / 255
model.compile(loss='sparse_categorical_crossentropy',
optimizer=keras.optimizers.RMSprop())
history = model.fit(x_train, y_train,
batch_size=64,
epochs=1)
predictions = model.predict(x_test)
Model: "3_layer_mlp"
_________________________________________________________________
Layer (type) Output Shape Param #
=================================================================
digits (InputLayer) [(None, 784)] 0
_________________________________________________________________
dense_1 (Dense) (None, 64) 50240
_________________________________________________________________
dense_2 (Dense) (None, 64) 4160
_________________________________________________________________
predictions (Dense) (None, 10) 650
=================================================================
Total params: 55,050
Trainable params: 55,050
Non-trainable params: 0
_________________________________________________________________
60000/60000 [==============================] - 2s 29us/sample - loss: 0.3116
1.1保持全模型
可以对整个模型进行保存，其保持的内容包括：
该模型的架构
模型的权重(在训练期间学到的)
模型的训练配置(你传递给编译的)，如果有的话
优化器及其状态(如果有的话)(这使您可以从中断的地方重新启动训练)
import numpy as np
model.save('the_save_model.h5')
new_model = keras.models.load_model('the_save_model.h5')
new_prediction = new_model.predict(x_test)
np.testing.assert_allclose(predictions, new_prediction, atol=1e-6) # 预测结果一样
1.2 保持为SavedModel文件
keras.experimental.export_saved_model(model, 'saved_model')
new_model = keras.experimental.load_from_saved_model('saved_model')
new_prediction = new_model.predict(x_test)
np.testing.assert_allclose(predictions, new_prediction, atol=1e-6) # 预测结果一样
### 1.3仅保存网络结构
仅保持网络结构，这样导出的模型并未包含训练好的参数
```python
config = model.get_config()
reinitialized_model = keras.Model.from_config(config)
new_prediction = reinitialized_model.predict(x_test)
assert abs(np.sum(predictions-new_prediction)) >0
也可以使用json保存网络结构
json_config = model.to_json()
reinitialized_model = keras.models.model_from_json(json_config)
new_prediction = reinitialized_model.predict(x_test)
assert abs(np.sum(predictions-new_prediction)) >0
1.4仅保存网络参数
weights = model.get_weights()
model.set_weights(weights)
# 可以把结构和参数保存结合起来
config = model.get_config()
weights = model.get_weights()
new_model = keras.Model.from_config(config) # config只能用keras.Model的这个api
new_model.set_weights(weights)
new_predictions = new_model.predict(x_test)
np.testing.assert_allclose(predictions, new_predictions, atol=1e-6)
1.5完整的模型保持方法
json_config = model.to_json()
with open('model_config.json', 'w') as json_file:
json_file.write(json_config)
model.save_weights('path_to_my_weights.h5')
with open('model_config.json') as json_file:
json_config = json_file.read()
new_model = keras.models.model_from_json(json_config)
new_model.load_weights('path_to_my_weights.h5')
new_predictions = new_model.predict(x_test)
np.testing.assert_allclose(predictions, new_predictions, atol=1e-6)
# 当然也可以一步到位
model.save('path_to_my_model.h5')
del model
model = keras.models.load_model('path_to_my_model.h5')
1.6保存网络权重为SavedModel格式
model.save_weights('weight_tf_savedmodel')
model.save_weights('weight_tf_savedmodel_h5', save_format='h5')
1.7子类模型参数保存
子类模型的结构无法保存和序列化，只能保持参数
# 构建模型无锡人流手术多少钱 http://www.chnk120.com/
class ThreeLayerMLP(keras.Model):
def __init__(self, name=None):
super(ThreeLayerMLP, self).__init__(name=name)
self.dense_1 = layers.Dense(64, activation='relu', name='dense_1')
self.dense_2 = layers.Dense(64, activation='relu', name='dense_2')
self.pred_layer = layers.Dense(10, activation='softmax', name='predictions')
def call(self, inputs):
x = self.dense_1(inputs)
x = self.dense_2(x)
return self.pred_layer(x)
def get_model():
return ThreeLayerMLP(name='3_layer_mlp')
model = get_model()
# 训练模型
(x_train, y_train), (x_test, y_test) = keras.datasets.mnist.load_data()
x_train = x_train.reshape(60000, 784).astype('float32') / 255
x_test = x_test.reshape(10000, 784).astype('float32') / 255
model.compile(loss='sparse_categorical_crossentropy',
optimizer=keras.optimizers.RMSprop())
history = model.fit(x_train, y_train,
batch_size=64,
epochs=1)
60000/60000 [==============================] - 2s 28us/sample - loss: 0.3217
# 保持权重参数
model.save_weights('my_model_weights', save_format='tf')
# 输出结果，供后面对比
predictions = model.predict(x_test)
first_batch_loss = model.train_on_batch(x_train[:64], y_train[:64])
# 读取保存的模型参数
new_model = get_model()
new_model.compile(loss='sparse_categorical_crossentropy',
optimizer=keras.optimizers.RMSprop())
#new_model.train_on_batch(x_train[:1], y_train[:1])
new_model.load_weights('my_model_weights')
new_predictions = new_model.predict(x_test)
np.testing.assert_allclose(predictions, new_predictions, atol=1e-6)
new_first_batch_loss = new_model.train_on_batch(x_train[:64], y_train[:64])
assert first_batch_loss == new_first_batch_loss
