1.这个neural network 的costfunction 看起来很复杂,其实把连加化简,就是上面的普通代价函数在神经网络的应用,只不过把每一层都加起来了. 为什么要初始化θ值? 后向传播涉及的公式的推导,把这些公式独立推导? 编程过程中的完整矩阵变换怎么变换的?…

1. Feedforward and cost function; 2.Regularized cost function: 3.Sigmoid gradient The gradient for the sigmoid function can be computed as: where: 4.Random initialization randInitializeWeights.m function W = randInitializeWeights(L_in, L_out) %RANDIN…

这学期一直在跟进 Coursera上的 Machina Learning 公开课, 老师Andrew Ng是coursera的创始人之一,Machine Learning方面的大牛.这门课程对想要了解和初步掌握机器学习的人来说是不二的选择.这门课程涵盖了机器学习的一些基本概念和方法,同时这门课程的编程作业对于掌握这些概念和方法起到了巨大的作用. 课程地址 https://www.coursera.org/learn/machine-learning 笔记主要是简要记录下课程内容,以及MATLAB…

0 - 学习目标 我们将实现一个简单的3层神经网络,我们不会仔细推到所需要的数学公式,但我们会给出我们这样做的直观解释.注意,此次代码并不能达到非常好的效果,可以自己进一步调整或者完成课后练习来进行改进. 1 - 实验步骤 1.1 - Import Packages # Package imports import matplotlib.pyplot as plt import numpy as np import sklearn import sklearn.datasets import s…

Principles of training multi-layer neural network using backpropagation http://galaxy.agh.edu.pl/~vlsi/AI/backp_t_en/backprop.html The project describes teaching process of multi-layer neural network employing backpropagation algorithm. To illustrate…

整理自Andrew Ng的machine learning 课程 week5. 目录: Neural network and classification Cost function Backpropagation (to minimize cost function) Backpropagation in practice Gradient checking Random initialization Assure structure and Train a neural network 前提…

Building your Deep Neural Network: Step by Step Welcome to your third programming exercise of the deep learning specialization. You will implement all the building blocks of a neural network and use these building blocks in the next assignment to bui…

Building your Recurrent Neural Network - Step by Step Welcome to Course 5's first assignment! In this assignment, you will implement your first Recurrent Neural Network in numpy. Recurrent Neural Networks (RNN) are very effective for Natural Language…

作者:zhbzz2007 出处:http://www.cnblogs.com/zhbzz2007 欢迎转载,也请保留这段声明.谢谢! 本文翻译自 RECURRENT NEURAL NETWORKS TUTORIAL, PART 1 – INTRODUCTION TO RNNS . Recurrent Neural Networks(RNNS) ,循环神经网络,是一个流行的模型,已经在许多NLP任务上显示出巨大的潜力.尽管它最近很流行,但是我发现能够解释RNN如何工作,以及如何实现RNN的资料很少…

神经网络的实践笔记 link: http://peterroelants.github.io/posts/neural_network_implementation_part01/ 1. 生成训练数据 import numpy as np import matplotlib.pyplot as plt # 神经网络中有关# 矩阵的运算我们采用NumPy来构建,# 画图使用Matplotlib来构建. # Part 1, create training data # Define the vect…