新手入门必备,可以尝试一下,这里可以直接用自己的数据集替换掉就好了,也可以私信我进行替换!
% Solve an Autoregression Time-Series Problem with a NAR Neural Network
% Script generated by Neural Time Series app
% Created 01-Mar-2023 19:33:45
%
% This script assumes this variable is defined:
%
% y - feedback time series.
clc
clear
load data.mat
y=data(:,8);
T = tonndata(y,false,false); %输入和输出矩阵须为cell类型的矩阵,且不能用num2cell来转换,如果使用二维cell矩阵,将会被认为是两个输入从而不能训练。
% Choose a Training Function
% For a list of all training functions type: help nntrain
% 'trainlm' is usually fastest.
% 'trainbr' takes longer but may be better for challenging problems.
% 'trainscg' uses less memory. Suitable in low memory situations.
trainFcn = 'trainlm'; % Levenberg-Marquardt backpropagation. %默认的lmh函数训练时间序列效果很差,采用贝叶斯正则化算法
% 对于大多数问题,推荐使用 Levenberg-Marquardt (trainlm),不过,对于一些含噪小型问题,贝叶斯正则化 (trainbr) 虽然可能需要更长的时间,但会获得更好的解。
%但是,对于大型问题,推荐使用量化共轭梯度 (trainscg),因为它使用的梯度计算比其他两种算法使用的 Jacobian 矩阵计算更节省内存。
%由于样本数据特性,此处选择贝叶斯正则化(Bayesian Regularization)。
% Create a Nonlinear Autoregressive Network
feedbackDelays = 1:20;%延迟向量1:10,即输出参考了前10个值
hiddenLayerSize = 10;
net = narnet(feedbackDelays,hiddenLayerSize,'open',trainFcn);
%这一项可以来调整神经元的个数,这个需要结合performance的误差来结合调整。一般地,靠增加隐层节点数来获得较低的误差,其训练效果要比增加隐层数更容易实现。
%需要注意的是,与在每一层中添加更多的神经元相比,添加层层数将获得更大的性能提升。因此,不要在一个隐藏层中加入过多的神经元。
% Prepare the Data for Training and Simulation
% The function PREPARETS prepares timeseries data for a particular network,
% shifting time by the minimum amount to fill input states and layer
% states. Using PREPARETS allows you to keep your original time series data
% unchanged, while easily customizing it for networks with differing
% numbers of delays, with open loop or closed loop feedback modes.
[x,xi,ai,t] = preparets(net,{},{},T);
% Setup Division of Data for Training, Validation, Testing
net.divideParam.trainRatio = 70/100;
net.divideParam.valRatio = 15/100;
net.divideParam.testRatio = 15/100;
% Train the Network
[net,tr] = train(net,x,t,xi,ai);
save('net,mat',net)
% Test the Network
y = net(x,xi,ai);
e = gsubtract(t,y);
performance = perform(net,t,y)
% View the Network
view(net)
% Plots
% Uncomment these lines to enable various plots.
%figure, plotperform(tr)
%figure, plottrainstate(tr)
%figure, ploterrhist(e)
%figure, plotregression(t,y)
%figure, plotresponse(t,y)
%figure, ploterrcorr(e)
%figure, plotinerrcorr(x,e)
% Closed Loop Network
% Use this network to do multi-step prediction.
% The function CLOSELOOP replaces the feedback input with a direct
% connection from the output layer.
netc = closeloop(net);
netc.name = [net.name ' - Closed Loop'];
view(netc)
[xc,xic,aic,tc] = preparets(netc,{},{},T);
yc = netc(xc,xic,aic);
closedLoopPerformance = perform(net,tc,yc)
% Step-Ahead Prediction Network
% For some applications it helps to get the prediction a timestep early.
% The original network returns predicted y(t+1) at the same time it is
% given y(t+1). For some applications such as decision making, it would
% help to have predicted y(t+1) once y(t) is available, but before the
% actual y(t+1) occurs. The network can be made to return its output a
% timestep early by removing one delay so that its minimal tap delay is now
% 0 instead of 1. The new network returns the same outputs as the original
% network, but outputs are shifted left one timestep.
nets = removedelay(net);
nets.name = [net.name ' - Predict One Step Ahead'];
view(nets)
[xs,xis,ais,ts] = preparets(nets,{},{},T);
ys = nets(xs,xis,ais);
stepAheadPerformance = perform(nets,ts,ys)