from keras.callbacks import TensorBoard
from keras.models import Sequential
from keras.optimizers import SGD, Adam
from keras.layers import Dense, Flatten, Dropout
from keras.layers.convolutional import Conv2D, MaxPooling2D
from keras.models import load_model
import keras
import numpy as np
from keras.applications.imagenet_utils import preprocess_input
from keras import backend as K
from keras.datasets import cifar10
from tensorflow.examples.tutorials.mnist import input_data
K.clear_session()
mnist = input_data.read_data_sets("MNIST_DATA", one_hot=True)
class AlexModel:
#初始化參數
def __init__(self, epochs, batch_size):
"""
:param epochs: 訓練集迭代的輪數
:param batch_size: 每次訓練的樣本的個數
"""
self.epochs = epochs
self.batch_size = batch_size
# 存儲訓練過程中的精度和誤差
self.train_accuracy_and_loss = None
# 創建模型
def build_model(self):
"""
創建模型, 基於alexnet
:return:
"""
model = Sequential()
#第一層卷積網絡,使用96個卷積核,大小爲11x11步長爲4, 要求輸入 1個通道,激活函數使用relu
model.add(Conv2D(96, (11, 11), strides=(4, 4), input_shape=(28, 28, 1), padding='valid', activation='relu',
kernel_initializer='uniform'))
# 池化層
model.add(MaxPooling2D(pool_size=(3, 3), strides=(2, 2), padding='valid'))
# 第二層加邊使用256個5x5的卷積核,加邊,激活函數爲relu
model.add(Conv2D(256, (5, 5), strides=(1, 1), padding='same', activation='relu', kernel_initializer='uniform'))
#使用池化層,步長爲2
model.add(MaxPooling2D(pool_size=(3, 3), strides=(2, 2), padding='same'))
# 第三層卷積,大小爲3x3的卷積核使用384個
model.add(Conv2D(384, (3, 3), strides=(1, 1), padding='same', activation='relu', kernel_initializer='uniform'))
# 第四層卷積,同第三層
model.add(Conv2D(384, (3, 3), strides=(1, 1), padding='same', activation='relu', kernel_initializer='uniform'))
# 第五層卷積使用的卷積核爲256個,其他同上
model.add(Conv2D(256, (3, 3), strides=(1, 1), padding='same', activation='relu', kernel_initializer='uniform'))
model.add(MaxPooling2D(pool_size=(3, 3), strides=(2, 2), padding='same'))
# 將卷積展開爲神經元
model.add(Flatten())
# 第1層隱藏全連接層使用4096個神經元
model.add(Dense(4096, activation='relu'))
# dropout正則化
model.add(Dropout(0.5))
# 第2層隱藏使用4096個神經元
model.add(Dense(4096, activation='relu'))
model.add(Dropout(0.5))
# 輸出層輸出類別個數
model.add(Dense(10, activation='softmax'))
# 選用adam優化器,學習率爲0.0003
adam = Adam(lr=0.0003, decay=1e-6)
# 編譯模型
model.compile(loss='categorical_crossentropy', optimizer=adam, metrics=['accuracy'])
return model
# 保存模型
def save_model_after_train(self):
model = self.build_model()
x_train, y_train = mnist.train.images, mnist.train.labels
x_train = x_train.reshape(55000, 28, 28, 1)
self.train_accuracy_and_loss = model.fit(x_train, y_train, batch_size=self.batch_size, epochs=self.epochs)
model.save("model.h5")
# 加載模型
def load_model(self):
return load_model("model.h5")
# 訓練模型
def train(self, mnist):
modle = self.build_model()
x_train, y_train = mnist.train.images, mnist.train.labels
x_train = x_train.reshape(55000, 28, 28, 1)
# {'acc': [], 'loss': []}
self.train_accuracy_and_loss = modle.fit(x_train, y_train, batch_size=self.batch_size,
epochs=self.epochs,
callbacks=[TensorBoard(log_dir='mytensorboard/3')])
# 獲取訓練過程中的損失(每個epoch)
def get_train_loss(self):
return self.train_accuracy_and_loss.history["loss"]
# 獲取訓練過程中的精度(每個epoch)
def get_train_accuracy(self):
return self.train_accuracy_and_loss.history["acc"]
# 測試集的精度和誤差
def test_accuracy_and_loss(self):
""""將訓練好的模型直接拿過來用"
:return: 返回精度和損失
"""
model = self.load_model()
x_test, y_test= mnist.test.images, mnist.test.labels
x_test = x_test.reshape(10000, 28, 28, 1)
score = model.evaluate(x_test, y_test, batch_size=32)
return score[1], score[0]
model = AlexModel(epochs=2, batch_size=256)
model.train(mnist)
loss = model.get_train_loss()
acc = model.get_train_accuracy()
print(acc)
使用AlexNet訓練mnist(面向對象)
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