使用model.save(filepath)将Keras模型和权重保存在一个HDF5文件中，该文件将包含：
模型的结构，以便重构该模型
模型的权重
训练配置（损失函数，优化器等）
优化器的状态，以便于从上次训练中断的地方开始
使用keras.models.load_model(filepath)来重新实例化你的模型，如果文件中存储了训练配置的话，该函数还会同时完成模型的编译
只保存模型结构,而不包含其权重或配置信息
#保存成json格式的文件
# save as JSONjson_string = model.to_json()
open('my_model_architecture.json','w').write(json_string)
from keras.models import model_from_json
model = model_from_json(open('my_model_architecture.json').read()) #保存成yaml文件
# save as YAML
yaml_string = model.to_yaml()
open('my_model_architectrue.yaml','w').write(yaml_string)
from keras.models import model_from_yaml
model = model_from_yaml(open('my_model_architecture.yaml').read())#这项操作将把模型序列化为json或yaml文件，这些文件对人而言也是友好的，如果需要的话你甚至可以手动打开这些文件并进行编辑。当然，你也可以从保存好的json文件或yaml文件中载入模型：# model reconstruction from JSON:
from keras.modelsimport model_from_json
model = model_from_json(json_string) # model reconstruction from YAML
model =model_from_yaml(yaml_string) 需要保存模型的权重
import keras.models import load_model
model.save_weights('my_model_weights.h5')
#需要在代码中初始化一个完全相同的模型
model.load_weights('my_model_weights.h5')
#需要加载权重到不同的网络结构（有些层一样）中，例如fine-tune或transfer-learning，可以通过层名字来加载模型
model.load_weights('my_model_weights.h5', by_name=True) open('my_model_architecture.json','w').write(json_string)
model.save_weights('my_model_weights.h5')
model = model_from_json(open('my_model_architecture.json').read())
model.load_weights('my_model_weights.h5')实时保存模型结构、训练出来的权重、及优化器状态并调用
keras 的callback参数可以帮助我们实现在训练过程中的适当时机被调用。实现实时保存训练模型以及训练参数
keras.callbacks.ModelCheckpoint(filepath, monitor='val_loss', verbose=0, save_best_only=False, save_weights_only=False, mode='auto', period=1
)1. filename：字符串，保存模型的路径
2. monitor：需要监视的值
3. verbose：信息展示模式，0或1
4. save_best_only：当设置为True时，将只保存在验证集上性能最好的模型
5. mode：‘auto’，‘min’，‘max’之一，在save_best_only=True时决定性能最佳模型的评判准则，例如，当监测值为val_acc时，模式应为max，当检测值为val_loss时，模式应为min。在auto模式下，评价准则由被监测值的名字自动推断。
6. save_weights_only：若设置为True，则只保存模型权重，否则将保存整个模型（包括模型结构，配置信息等）
7. period：CheckPoint之间的间隔的epoch数示例
"""
假如原模型为：model = Sequential()model.add(Dense(2, input_dim=3, name="dense_1"))model.add(Dense(3, name="dense_2"))...model.save_weights(fname)
"""
# new model
model = Sequential()
model.add(Dense(2, input_dim=3, name="dense_1")) # will be loaded
model.add(Dense(10, name="new_dense")) # will not be loaded# load weights from first model; will only affect the first layer, dense_1.
model.load_weights(fname, by_name=True)How to Check-Point Deep Learning Models in Keras
Checkpoint Neural Network Model Improvements
# Checkpoint the weights when validation accuracy improves
from keras.models import Sequential
from keras.layers import Dense
from keras.callbacks import ModelCheckpoint
import matplotlib.pyplot as plt
import numpy
# fix random seed for reproducibility
seed = 7
numpy.random.seed(seed)
# load pima indians dataset
dataset = numpy.loadtxt("pima-indians-diabetes.csv", delimiter=",")
# split into input (X) and output (Y) variables
X = dataset[:,0:8]
Y = dataset[:,8]
# create model
model = Sequential()
model.add(Dense(12, input_dim=8, kernel_initializer='uniform', activation='relu'))
model.add(Dense(8, kernel_initializer='uniform', activation='relu'))
model.add(Dense(1, kernel_initializer='uniform', activation='sigmoid'))
# Compile model
model.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy'])
# checkpoint
filepath="weights-improvement-{epoch:02d}-{val_acc:.2f}.hdf5"
checkpoint = ModelCheckpoint(filepath, monitor='val_acc', verbose=1, save_best_only=True, mode='max')
callbacks_list = [checkpoint]
# Fit the model
model.fit(X, Y, validation_split=0.33, epochs=150, batch_size=10, callbacks=callbacks_list, verbose=0)Running the example produces the following output (truncated for brevity):
...
Epoch 00134: val_acc did not improve
Epoch 00135: val_acc did not improve
Epoch 00136: val_acc did not improve
Epoch 00137: val_acc did not improve
Epoch 00138: val_acc did not improve
Epoch 00139: val_acc did not improve
Epoch 00140: val_acc improved from 0.83465 to 0.83858, saving model to weights-improvement-140-0.84.hdf5
Epoch 00141: val_acc did not improve
Epoch 00142: val_acc did not improve
Epoch 00143: val_acc did not improve
Epoch 00144: val_acc did not improve
Epoch 00145: val_acc did not improve
Epoch 00146: val_acc improved from 0.83858 to 0.84252, saving model to weights-improvement-146-0.84.hdf5
Epoch 00147: val_acc did not improve
Epoch 00148: val_acc improved from 0.84252 to 0.84252, saving model to weights-improvement-148-0.84.hdf5
Epoch 00149: val_acc did not improveYou will see a number of files in your working directory containing the network weights in HDF5 format. For example:
...
weights-improvement-53-0.76.hdf5
weights-improvement-71-0.76.hdf5
weights-improvement-77-0.78.hdf5
weights-improvement-99-0.78.hdf5Checkpoint Best Neural Network Model Only
# Checkpoint the weights for best model on validation accuracy
from keras.models import Sequential
from keras.layers import Dense
from keras.callbacks import ModelCheckpoint
import matplotlib.pyplot as plt
import numpy
# fix random seed for reproducibility
seed = 7
numpy.random.seed(seed)
# load pima indians dataset
dataset = numpy.loadtxt("pima-indians-diabetes.csv", delimiter=",")
# split into input (X) and output (Y) variables
X = dataset[:,0:8]
Y = dataset[:,8]
# create model
model = Sequential()
model.add(Dense(12, input_dim=8, kernel_initializer='uniform', activation='relu'))
model.add(Dense(8, kernel_initializer='uniform', activation='relu'))
model.add(Dense(1, kernel_initializer='uniform', activation='sigmoid'))
# Compile model
model.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy'])
# checkpoint
filepath="weights.best.hdf5"
checkpoint = ModelCheckpoint(filepath, monitor='val_acc', verbose=1, save_best_only=True, mode='max')
callbacks_list = [checkpoint]
# Fit the model
model.fit(X, Y, validation_split=0.33, epochs=150, batch_size=10, callbacks=callbacks_list, verbose=0)Running this example provides the following output (truncated for brevity):
...
Epoch 00139: val_acc improved from 0.79134 to 0.79134, saving model to weights.best.hdf5
Epoch 00140: val_acc did not improve
Epoch 00141: val_acc did not improve
Epoch 00142: val_acc did not improve
Epoch 00143: val_acc did not improve
Epoch 00144: val_acc improved from 0.79134 to 0.79528, saving model to weights.best.hdf5
Epoch 00145: val_acc improved from 0.79528 to 0.79528, saving model to weights.best.hdf5
Epoch 00146: val_acc did not improve
Epoch 00147: val_acc did not improve
Epoch 00148: val_acc did not improve
Epoch 00149: val_acc did not improveYou should see the weight file in your local directory.
weights.best.hdf5Loading a Check-Pointed Neural Network Model
# How to load and use weights from a checkpoint
from keras.models import Sequential
from keras.layers import Dense
from keras.callbacks import ModelCheckpoint
import matplotlib.pyplot as plt
import numpy
# fix random seed for reproducibility
seed = 7
numpy.random.seed(seed)
# create model
model = Sequential()
model.add(Dense(12, input_dim=8, kernel_initializer='uniform', activation='relu'))
model.add(Dense(8, kernel_initializer='uniform', activation='relu'))
model.add(Dense(1, kernel_initializer='uniform', activation='sigmoid'))
# load weights
model.load_weights("weights.best.hdf5")
# Compile model (required to make predictions)
model.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy'])
print("Created model and loaded weights from file")
# load pima indians dataset
dataset = numpy.loadtxt("pima-indians-diabetes.csv", delimiter=",")
# split into input (X) and output (Y) variables
X = dataset[:,0:8]
Y = dataset[:,8]
# estimate accuracy on whole dataset using loaded weights
scores = model.evaluate(X, Y, verbose=0)
print("%s: %.2f%%" % (model.metrics_names[1], scores[1]*100))Running the example produces the following output
Created model and loaded weights from file
acc: 77.73%参考文献
How to Check-Point Deep Learning Models in Keras
http://blog.csdn.net/u010159842/article/details/54602217
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