keras的例子，参照可完整实现所有代码

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我是靠谱客的博主有魅力小笼包，最近开发中收集的这篇文章主要介绍keras的例子，参照可完整实现所有代码，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

https://blog.csdn.net/liuxiao214/article/details/79027109

后面有时间再在这总结一下keras的特点以及如何去使用。

-------------------------------------先把位置占着-------------

哈哈

Keras分为两种不同的建模方式，

Sequential models：这种方法用于实现一些简单的模型。你只需要向一些存在的模型中添加层就行了。
Functional API：Keras的API是非常强大的，你可以利用这些API来构造更加复杂的模型，比如多输出模型，有向无环图等等

下面是模型的定义：如果想要添加之间add就可以了相当于先定义模型队列，然后再在里面添加一层一层的网络

def define_model():

model = Sequential()

# setup first conv layer
model.add(Conv2D(32, (3, 3), activation="relu",
input_shape=(120, 120, 3), padding='same')) # [10, 120, 120, 32]

# setup first maxpooling layer
model.add(MaxPooling2D(pool_size=(2, 2))) # [10, 60, 60, 32]

# setup second conv layer
model.add(Conv2D(8, kernel_size=(3, 3), activation="relu",
padding='same')) # [10, 60, 60, 8]

# setup second maxpooling layer
model.add(MaxPooling2D(pool_size=(3, 3))) # [10, 20, 20, 8]

# add bianping layer, 3200 = 20 * 20 * 8
model.add(Flatten()) # [10, 3200]

# add first full connection layer
model.add(Dense(512, activation='sigmoid')) # [10, 512]

# add dropout layer
model.add(Dropout(0.5))

# add second full connection layer
model.add(Dense(4, activation='softmax')) # [10, 4]

return model

#下面的是训练模型，加载数据的模型因为每个人的数据形式不一样都要进行转化，所以有需要的直接去最上面的链接上面去找就可以了。

#关于训练模型，包括下面几个阶段：

1 调用之前定义的网络模型

2 定义优化器，具体如何调用优化器呢？keras与pytorch一样都很方便，from keras.optimizers import SGD

3 进行模型编译，也就是把模型的损失与优化器，融合到一起加载到模型中方便后面进行模型训练

4 如果想用自己的损失函数的话，需要自己定义，当然常用的都在keras库中包含了from keras.losses import categorical_crossentropy

5 model.summary()

6 model.fit()

7 model.evaluate()

def train_model(resultpath):
model = define_model()

# if want to use SGD, first define sgd, then set optimizer=sgd
sgd = SGD(lr=0.001, decay=1e-6, momentum=0, nesterov=True)

# select lossoptimizer
model.compile(loss=categorical_crossentropy,
optimizer=Adam(), metrics=['accuracy'])
model.summary()

# draw the model structure
plot_model(model, show_shapes=True,
to_file=os.path.join(resultpath, 'model.png'))

# load data
X, Y = load_data(resultpath)

# split train and test data
X_train, X_test, Y_train, Y_test = train_test_split(
X, Y, test_size=0.2, random_state=2)

# input data to model and train
history = model.fit(X_train, Y_train, batch_size=2, epochs=10,
validation_data=(X_test, Y_test), verbose=1, shuffle=True)

# evaluate the model
loss, acc = model.evaluate(X_test, Y_test, verbose=0)
print('Test loss:', loss)
print('Test accuracy:', acc)

保存模型，加载模型可参考完整代码如下：

from keras.models import Sequential
from keras.layers import Dense, Conv2D, MaxPooling2D, Flatten, Dropout
from keras.losses import categorical_crossentropy
from keras.optimizers import Adam
from keras.utils.vis_utils import plot_model
from keras.optimizers import SGD
from keras.models import model_from_json
from keras.models import load_model
from keras.utils import np_utils
import numpy as np
import os
from sklearn.model_selection import train_test_split

def load_data(resultpath):
datapath = os.path.join(resultpath, "data10_4.npz")
if os.path.exists(datapath):
data = np.load(datapath)
X, Y = data["X"], data["Y"]
else:
X = np.array(np.arange(432000)).reshape(10, 120, 120, 3)
Y = [0, 0, 1, 1, 2, 2, 3, 3, 2, 0]
X = X.astype('float32')
Y = np_utils.to_categorical(Y, 4)
np.savez(datapath, X=X, Y=Y)
print('Saved dataset to dataset.npz.')
print('X_shape:{}nY_shape:{}'.format(X.shape, Y.shape))
return X, Y

def define_model():
model = Sequential()

# setup first conv layer
model.add(Conv2D(32, (3, 3), activation="relu",
input_shape=(120, 120, 3), padding='same')) # [10, 120, 120, 32]

# setup first maxpooling layer
model.add(MaxPooling2D(pool_size=(2, 2))) # [10, 60, 60, 32]

# setup second conv layer
model.add(Conv2D(8, kernel_size=(3, 3), activation="relu",
padding='same')) # [10, 60, 60, 8]

# setup second maxpooling layer
model.add(MaxPooling2D(pool_size=(3, 3))) # [10, 20, 20, 8]

# add bianping layer, 3200 = 20 * 20 * 8
model.add(Flatten()) # [10, 3200]

# add first full connection layer
model.add(Dense(512, activation='sigmoid')) # [10, 512]

# add dropout layer
model.add(Dropout(0.5))

# add second full connection layer
model.add(Dense(4, activation='softmax')) # [10, 4]

return model

def train_model(resultpath):
model = define_model()

# if want to use SGD, first define sgd, then set optimizer=sgd
sgd = SGD(lr=0.001, decay=1e-6, momentum=0, nesterov=True)

# select lossoptimizer
model.compile(loss=categorical_crossentropy,
optimizer=Adam(), metrics=['accuracy'])
model.summary()

# draw the model structure
plot_model(model, show_shapes=True,
to_file=os.path.join(resultpath, 'model.png'))

# load data
X, Y = load_data(resultpath)

# split train and test data
X_train, X_test, Y_train, Y_test = train_test_split(
X, Y, test_size=0.2, random_state=2)

# input data to model and train
history = model.fit(X_train, Y_train, batch_size=2, epochs=10,
validation_data=(X_test, Y_test), verbose=1, shuffle=True)

# evaluate the model
loss, acc = model.evaluate(X_test, Y_test, verbose=0)
print('Test loss:', loss)
print('Test accuracy:', acc)

return model

def my_save_model(resultpath):

model = train_model(resultpath)

# the first way to save model
model.save(os.path.join(resultpath, 'my_model.h5'))

# the secon way : save trained network structure and weights
model_json = model.to_json()
open(os.path.join(resultpath, 'my_model_structure.json'), 'w').write(model_json)
model.save_weights(os.path.join(resultpath, 'my_model_weights.hd5'))

def my_load_model(resultpath):

# test data
X = np.array(np.arange(86400)).reshape(2, 120, 120, 3)
Y = [0, 1]
X = X.astype('float32')
Y = np_utils.to_categorical(Y, 4)

# the first way of load model
model2 = load_model(os.path.join(resultpath, 'my_model.h5'))
model2.compile(loss=categorical_crossentropy,
optimizer=Adam(), metrics=['accuracy'])

test_loss, test_acc = model2.evaluate(X, Y, verbose=0)
print('Test loss:', test_loss)
print('Test accuracy:', test_acc)

y = model2.predict_classes(X)
print("predicct is: ", y)

# the second way : load model structure and weights
model = model_from_json(open(os.path.join(resultpath, 'my_model_structure.json')).read())
model.load_weights(os.path.join(resultpath, 'my_model_weights.hd5'))
model.compile(loss=categorical_crossentropy,
optimizer=Adam(), metrics=['accuracy'])

test_loss, test_acc = model.evaluate(X, Y, verbose=0)
print('Test loss:', test_loss)
print('Test accuracy:', test_acc)

y = model.predict_classes(X)
print("predicct is: ", y)

def main():
resultpath = "result"
#train_model(resultpath)
#my_save_model(resultpath)
my_load_model(resultpath)

if __name__ == "__main__":
main()