文章目录

• 1.HDF5文件
• 2.github代码：
• 3.源码地址：
• 4.tf入门合集

1.HDF5文件

到目前为止，我们使用的数据集都能够全部加载到内存中。对于小数据集，我们可以加载全部图像数据到内存中，进行预处理，并进行前向传播处理。然而，对于大规模数据集(比如ImageNet),我们需要创建数据生成器，每次只访问一小部分数据集（比如mini-batch），然后对batch数据进行预处理和前向传播。

Keras模块很方便进行数据加载，可以使用磁盘上的原始文件路径作为训练过程的输入。你不需要将整个数据集存储在内存中——只需为Keras数据生成器提供图像路径，生成器会自动从路径中加载数据并进行前向传播。

然而，这种方法非常低效。读取磁盘上的每张图像都需要一个I/O操作，这样会造成一定的延迟。训练深度学习网络本身已经够慢了，所以我们应该尽可能避免I/O瓶颈。

一个比较合理的解决方案是将原始图像生成HDF5数据集，，只是这一次我们存储的是原始图像，而不是提取的特征。HDF5不仅可以存储大量的数据集，而且还可以用于I/O操作，特别是用于从文件中提取batch(称为“片”)。我们将在磁盘上的原始图像保存到HDF5文件中，这可以让模型快速的遍历数据集并在其上训练深度学习网络。

2.github代码：

# -*- coding: utf-8 -*-
"""
Example on how to use HDF5 dataset with TFLearn. HDF5 is a data model,
library, and file format for storing and managing data. It can handle large
dataset that could not fit totally in ram memory. Note that this example
just give a quick compatibility demonstration. In practice, there is no so
real need to use HDF5 for small dataset such as CIFAR-10.
"""

from __future__ import division, print_function, absolute_import

import tflearn
from tflearn.layers.core import *
from tflearn.layers.conv import *
from tflearn.data_utils import *
from tflearn.layers.normalization import *
from tflearn.layers.estimator import regression

# CIFAR-10 Dataset
from tflearn.datasets import cifar10
(X, Y), (X_test, Y_test) = cifar10.load_data()
Y = to_categorical(Y)
Y_test = to_categorical(Y_test)

# Create a hdf5 dataset from CIFAR-10 numpy array
import h5py
h5f = h5py.File('data.h5', 'w')
h5f.create_dataset('cifar10_X', data=X)
h5f.create_dataset('cifar10_Y', data=Y)
h5f.create_dataset('cifar10_X_test', data=X_test)
h5f.create_dataset('cifar10_Y_test', data=Y_test)
h5f.close()

# Load hdf5 dataset
h5f = h5py.File('data.h5', 'r')
X = h5f['cifar10_X']
Y = h5f['cifar10_Y']
X_test = h5f['cifar10_X_test']
Y_test = h5f['cifar10_Y_test']

# Build network
network = input_data(shape=[None, 32, 32, 3], dtype=tf.float32)
network = conv_2d(network, 32, 3, activation='relu')
network = max_pool_2d(network, 2)
network = conv_2d(network, 64, 3, activation='relu')
network = conv_2d(network, 64, 3, activation='relu')
network = max_pool_2d(network, 2)
network = fully_connected(network, 512, activation='relu')
network = dropout(network, 0.5)
network = fully_connected(network, 10, activation='softmax')
network = regression(network, optimizer='adam',
                     loss='categorical_crossentropy',
                     learning_rate=0.001)

# Training
model = tflearn.DNN(network, tensorboard_verbose=0)
model.fit(X, Y, n_epoch=50, shuffle=True, validation_set=(X_test, Y_test),
          show_metric=True, batch_size=96, run_id='cifar10_cnn')

h5f.close()

3.源码地址：

https://github.com/tflearn/tflearn/blob/master/examples/basics/use_hdf5.py

4.tf入门合集

https://blog.csdn.net/bigquant/article/details/85339665?depth_1-utm_source=distribute.pc_relevant.none-task&utm_source=distribute.pc_relevant.none-task