自编码分类器神经网络记录

本人于2019年秋季参加了学校开设的深度学习相关课程，在大作业中遇到的困难在此记录一二(part of pictures from Doc.ZhangYi)，整体思路如下：

1.Train the autoencoder by using unlabeled data

Read and prepare the data. Train the autoencoder by using unlabeled data (the unlabeled set). Remove the layers behind sparse representation layer after training

数据集数量：7800数据集内容：猫狗图片单个样本大小：300*400

自编码惩罚函数

加入稀疏优化注意事项

训练1(fail)

max_iter = 600mini_batch = 40alpha = 0.01data：80x80x200

% 神经网络结构
layer_size = [input_size 1000
                       0 2000
                       0 500
                       0 2000
                       0 input_size];
% 激活函数设计
fs = {[], relu, relu, relu, relu, relu, relu, relu};
dfs = {[], drelu, drelu, drelu, drelu, drelu, drelu, drelu};
% 权值初始化
w{l} = (rand(layer_size(l+1, 2), sum(layer_size(l, :)))*2-1) * 0.01;
% 定义cost function
J_y = [J_y 1/2/mini_batch*sum((a{L}(:)-y(:)).^2)];

左图为误差曲线、w{1-4}的均值与方差(rgbk)，右图为w{1-4}的最终分布

最后一轮a{1-5}的分布

效果不容乐观啊

训练2(fail)

max_iter = 800mini_batch = 40alpha = 0.2data：80x80x200

% 神经网络结构
layer_size = [input_size 1000
                       0 2000
                       0 500
                       0 2000
                       0 input_size];
% 激活函数设计
fs = {[], sigm, sigm, sigm, sigm, sigm, sigm, sigm};
dfs = {[], dsigm, dsigm, dsigm, dsigm, dsigm, dsigm, dsigm};
% 权值初始化
w{l} = (randn(layer_size(l+1, 2), sum(layer_size(l, :)))*2-1) *  sqrt(6/( layer_size(l+1, 2) + sum(layer_size(l,:)) ));
% 定义cost function
J_y = [J_y 1/2/mini_batch*sum((a{L}(:)-y(:)).^2)];

训练3(fail)

max_iter = 600mini_batch = 40alpha = 0.2data：80x80x200layer_size: input+1000(0);2000;1000;500;1000;2000;outputw: (2*randn()-1)*sqrt(6/(n{l}+n{l+1}))sigmoidJ: 0.5/mini_batch*Σ(a{L}-y)

训练4(fail)

max_iter = 600mini_batch = 50alpha = 0.3data：80x80x200layer_size: input+1000(0);2000;500;30;500;2000;outputw: randn()*sqrt(6/(n{l}+n{l+1}))sigmoidJ: 0.5/mini_batch*Σ(a{L}-y)

emmmm，再来600轮（上面的a和w少了几张）

训练5

max_iter = 900mini_batch = 40alpha = 0.3data：80x80x1000layer_size: input+1000(0);2000;500;2000;outputw: randn()*sqrt(6/(n{l}+n{l+1}))sigmoidJ: 0.5/mini_batch*Σ(a{L}-y)

这次看上去像是要成功，结果断断续续训练了7个小时左右matlab犯病了...看来以后不能开这么多图了。实际经过1000+轮后误差降到1左右。

训练5-1

上接train5-1…max_iter = 900beta= 0.1
emmm，采用训练5所得的权值接着进行稀疏优化，可能beta还是0.1好一些

2.Training the network by using the new training data set

Form a new data set in sparse representation layer by using the labeled data set (the trianing set). Form a new training data set for supervised network (the encoded training set and its labels). Training the network by using the new training data set

3.combine the two networks

4.test the network with the testing set

训练1

max_iter = 400mini_batch = 40alpha = 0.05data：500x320layer_size: input(500)+0;126;32;8;2w: randn()*sqrt(6/(n{l}+n{l+1}))sigmoidJ: 0.5/mini_batch*Σ(a{L}-y)