1506.01186-Cyclical Learning Rates for Training Neural Networks 论文中提出了一种循环调整学习率来训练模型的方式. 如下图: 通过循环的线性调整学习率,论文作者观察到的一种比较典型的曲线如下图: 图中,使用循环调整方式的模型,虽然训练中准确度有很大的波动,但是这种波动并不影像模型很快的收敛,并且以更快的速度收敛到了固定学习率或者学习率衰减方案中能达到的最高准确率. 这种方式需要设置的超参有三个, min bound,max bound…
A Recipe for Training Neural Networks Andrej Karpathy blog  2019-04-27 09:37:05 This blog is copied from:https://karpathy.github.io/2019/04/25/recipe/ Some few weeks ago I posted a tweet on “the most common neural net mistakes”, listing a few common…
CS231n Winter 2016: Lecture 5: Neural Networks Part 2 CS231n Winter 2016: Lecture 6: Neural Networks Part 3 by Andrej Karpathy 本章节主要讲解激活函数,参数初始化以及周边的知识体系. Ref: <深度学习>第八章 - 深度模型中的优化 Overview 1. One time setup activation functions, preprocessing, weig…
声明:所有内容来自coursera,作为个人学习笔记记录在这里. 请不要ctrl+c/ctrl+v作业. Optimization Methods Until now, you've always used Gradient Descent to update the parameters and minimize the cost. In this notebook, you will learn more advanced optimization methods that can spee…
Training Neural Networks: Q&A with Ian Goodfellow, Google Neural networks require considerable time and computational firepower to train. Previously, researchers believed that neural networks were costly to train because gradient descent slows down n…
背景: 做大规模机器学习算法,特别是神经网络最怕什么--没有数据!!没有数据意味着,机器学不会,人工不智能!通常使用样本增强来扩充数据一直都是解决这个问题的一个好方法. 最近的一篇论文<Training Neural Networks with Very Little Data-A Draft>提出了一个新的图像样本增强方法:对图像使用径向变换生成不同"副本",解决样本数量太少难以训练的问题.论文地址:https://arxiv.org/pdf/1708.04347.pdf…
原文:https://medium.com/learning-new-stuff/how-to-learn-neural-networks-758b78f2736e#.ly5wpz44d This is the second post in a series of me trying to learn something new over a short period of time. The first time consisted of learning how to do machine…
最近拜读大神Karpathy的经验之谈 A Recipe for Training Neural Networks  https://karpathy.github.io/2019/04/25/recipe/,这个秘籍对很多深度学习算法训练过程中遇到的各自问题进行了总结,并提出了很多很好的建议,翻译于此,希望能够帮助更多人学到这些内容. 译文如下: 几周前,我发布了一条关于“最常见的神经网络错误”的推文,列出了一些与训练神经网络相关的常见问题.这条推文得到了比我预期的要多得多的认同(包括网络研讨…
课程主页:http://cs231n.stanford.edu/   Introduction to neural networks -Training Neural Network ______________________________________________________________________________________________________________________________________________________________…
声明:所有内容来自coursera,作为个人学习笔记记录在这里. Initialization Welcome to the first assignment of "Improving Deep Neural Networks". Training your neural network requires specifying an initial value of the weights. A well chosen initialization method will help…
Week 3 Quiz - Shallow Neural Networks(第三周测验 - 浅层神经网络) \1. Which of the following are true? (Check all that apply.) Notice that I only list correct options(以下哪一项是正确的?只列出了正确的答案) [ ]…
原文: 二值神经网络(Binary Neural Network,BNN) 在我刚刚过去的研究生毕设中,我在ImageNet数据集上验证了图像特征二值化后仍然具有很强的表达能力,可以在检索中达到较好的效果.而Bengio大神的这篇文章,则不止于将特征二值化,而是要将权重和每层的激活值统统二值化.相比于非二值化的网络,将大量的数学运算变成了位操作.这样就节省了大量的空间而前向传播的时间,使神经网络的应用门槛变得更低. 本文是阅读Bengio二值化网络文章的笔记,特此声明. 要想使整个神经网络二值化…
声明:所有内容来自coursera,作为个人学习笔记记录在这里. Gradient Checking Welcome to the final assignment for this week! In this assignment you will learn to implement and use gradient checking. You are part of a team working to make mobile payments available globally, and…
声明:所有内容来自coursera,作为个人学习笔记记录在这里. Regularization Welcome to the second assignment of this week. Deep Learning models have so much flexibility and capacity that overfitting can be a serious problem, if the training dataset is not big enough. Sure it do…
Tuning process 下图中的需要tune的parameter的先后顺序, 红色>黄色>紫色,其他基本不会tune. 先讲到怎么选hyperparameter, 需要随机选取(sampling at random) 随机选取的过程中,可以采用从粗到细的方法逐步确定参数 有些参数可以按照线性随机选取, 比如 n[l] 但是有些参数就不适合线性的sampling at radom, 比如 learning rate α,这时可以用 log Andrew 很幽默的讲到了两种选参数的实际场景…
Train/Dev/Test set Bias/Variance Regularization  有下面一些regularization的方法. L2 regularation drop out data augmentation(翻转图片得到一个新的example), early stopping(画出J_train 和J_dev 对应于iteration的图像) L2 regularization: Forbenius Norm. 上面这张图提到了weight decay 的概念 Weigh…
课程主页:http://cs231n.stanford.edu/ _______________________________________________________________________________________________________________________________________________________ -Parameter Updates 解决的方法: *Momentum update 其实就是把x再加上mu*v(可以看作是下滑过…
1. 优化: 1.1 随机梯度下降法(Stochasitc Gradient Decent, SGD)的问题: 1)对于condition number(Hessian矩阵最大和最小的奇异值的比值)很大的loss function,一个方向梯度变化明显,另一个方向梯度变化很缓慢,SGD在优化过程中会震荡着下降,导致优化很慢.深度学习的网络会有上百万甚至更多的参数需要优化,在这个上百万维的空间里,更容易出现各个维度梯度变化差别很大的问题. 2)陷落在局部最小点或者鞍点(saddle point).…
1. 激活函数: 1)Sigmoid,σ(x)=1/(1+e-x).把输出压缩在(0,1)之间.几个问题:(a)x比较大或者比较小(比如10,-10),sigmoid的曲线很平缓,导数为0,在用链式法则的时候,后一层传回来的导数乘以sigmoid的导数也是0了,换句话说,对于sigmoid饱和的区域后一层的导数传不到前面去了.(b)输出永远为正,即下一层的输入永远为正,我们希望输入的均值为0.(c)exp还是稍微有点难计算. 2)tanh(x),输出压缩在[-1,+1]之间,比sigmoid的进…
Gradient descent Batch Gradient Decent, Mini-batch gradient descent, Stochastic gradient descent 还有很多比gradient decent 更优化的算法,在了解这些算法前,需要先理解  Exponentially weighted averages 这个概念 Exponentially weighted average 是一种计算平均值的方法,非常省storage 和 memory, 但是不是很精确.…
1. 优化: 1.1 随机梯度下降法(Stochasitc Gradient Decent, SGD)的问题: 1)对于condition number(Hessian矩阵最大和最小的奇异值的比值)很大的loss function,一个方向梯度变化明显,另一个方向梯度变化很缓慢,SGD在优化过程中会震荡着下降,导致优化很慢.深度学习的网络会有上百万甚至更多的参数需要优化,在这个上百万维的空间里,更容易出现各个维度梯度变化差别很大的问题. 2)陷落在局部最小点或者鞍点(saddle point).…
1. 激活函数: 1)Sigmoid,σ(x)=1/(1+e-x).把输出压缩在(0,1)之间.几个问题:(a)x比较大或者比较小(比如10,-10),sigmoid的曲线很平缓,导数为0,在用链式法则的时候,后一层传回来的导数乘以sigmoid的导数也是0了,换句话说,对于sigmoid饱和的区域后一层的导数传不到前面去了.(b)输出永远为正,即下一层的输入永远为正,我们希望输入的均值为0.(c)exp还是稍微有点难计算. 2)tanh(x),输出压缩在[-1,+1]之间,比sigmoid的进…
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原文链接:https://developers.google.com/machine-learning/crash-course/training-neural-networks/ 反向传播算法是最常见的一种神经网络训练算法.借助这种算法,梯度下降法在多层神经网络中将成为可行方法.TensorFlow 可自动处理反向传播算法,因此不需要对该算法作深入研究. 1- 最佳做法 1.1 失败案例 很多常见情况都会导致反向传播算法出错. 梯度消失 较低层(更接近输入)的梯度可能会变得非常小.在深度网络中…
About this Course If you want to break into cutting-edge AI, this course will help you do so. Deep learning engineers are highly sought after, and mastering deep learning will give you numerous new career opportunities. Deep learning is also a new "s…
ON THE EVOLUTION OF MACHINE LEARNING: FROM LINEAR MODELS TO NEURAL NETWORKS We recently interviewed Reza Zadeh (@Reza_Zadeh). Reza is a Consulting Professor in the Institute for Computational and Mathematical Engineering at Stanford University and a…
Training (deep) Neural Networks Part: 1 Nowadays training deep learning models have become extremely easy with high-quality libraries such as Torch and Theano. These libraries are really helpful for rapidly prototyping deep learning models even witho…
Neural Networks and Deep Learning This is the first course of the deep learning specialization at Coursera which is moderated by moderated by DeepLearning.ai. The course is taught by Andrew Ng. Introduction to deep learning Be able to explain the maj…
译自:http://sebastianruder.com/multi-task/ 1. 前言 在机器学习中,我们通常关心优化某一特定指标,不管这个指标是一个标准值,还是企业KPI.为了达到这个目标,我们训练单一模型或多个模型集合来完成指定得任务.然后,我们通过精细调参,来改进模型直至性能不再提升.尽管这样做可以针对一个任务得到一个可接受得性能,但是我们可能忽略了一些信息,这些信息有助于在我们关心的指标上做得更好.具体来说,这些信息就是相关任务的监督数据.通过在相关任务间共享表示信息,我们的模型在…
Hacker's guide to Neural Networks Hi there, I'm a CS PhD student at Stanford. I've worked on Deep Learning for a few years as part of my research and among several of my related pet projects is ConvNetJS - a Javascript library for training Neural Net…