MATLAB: Neural network multiple output with different units

different unitsmultiple outputneural network

I'm trying to build a network with 4 inputs and 2 outputs. In the output are different units like µm and percent. At the end of the NN calculation I want to get the mean squared error, but how can I interpret this error when there are different units. For example a mse of 1 µm is very good and also a mse of 5 % would be great, too for another output.
% Solve an Input-Output Fitting problem with a Neural Network
% Script generated by Neural Fitting app
% Created 07-Dec-2016 07:33:26

% This script assumes these variables are defined:
% OptiSlangExport_woKW - input data.
% Sa - target data.
close all
x = OptiSlangExport_woKW';
t = Sa';
% 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.
trainFcn = 'trainbr';
% Create a Fitting Network
hiddenLayerSize = 7;
net = fitnet(hiddenLayerSize,trainFcn);
% Choose Input and Output Pre/Post-Processing Functions
% For a list of all processing functions type: help nnprocess
net.input.processFcns = {'removeconstantrows','mapminmax'};
net.output.processFcns = {'removeconstantrows','mapminmax'};
% Setup Division of Data for Training, Validation, Testing
% For a list of all data division functions type: help nndivide
net.divideFcn = 'dividerand'; % Divide data randomly
net.divideMode = 'sample'; % Divide up every sample
net.divideParam.trainRatio = 90/100;
% net.divideParam.valRatio = 35/100; % No Validation when using trainbr
net.divideParam.testRatio = 10/100;
% Choose a Performance Function
% For a list of all performance functions type: help nnperformance
% net.performFcn = 'crossentropy'; %Mean absolut Error
net.performFcn = 'mse'; % Mean Squared Error
% Choose Plot Functions
% For a list of all plot functions type: help nnplot
net.plotFcns = {'plotperform','plottrainstate','ploterrhist', ...
'plotregression', 'plotfit'};
% Train the Network
[net,tr] = train(net,x,t);
% Test the Network
y = net(x);
e = gsubtract(t,y);
performance = perform(net,t,y)
% Recalculate Training, Validation and Test Performance
trainTargets = t .* tr.trainMask{1};
valTargets = t .* tr.valMask{1};
testTargets = t .* tr.testMask{1};
trainPerformance = perform(net,trainTargets,y)
valPerformance = perform(net,valTargets,y)
testPerformance = perform(net,testTargets,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)
% plotregression(trTarg,trOut,'Train',vTarg,vOut,'Validation',...
% tsTarg,tsOut,'Testing')
% figure, plotfit(net,x,t)
% Deployment
% Change the (false) values to (true) to enable the following code blocks.
% See the help for each generation function for more information.
if (false)
% Generate MATLAB function for neural network for application
% deployment in MATLAB scripts or with MATLAB Compiler and Builder
% tools, or simply to examine the calculations your trained neural
% network performs.
y = myNeuralNetworkFunction(x);
if (false)
% Generate a matrix-only MATLAB function for neural network code
% generation with MATLAB Coder tools.
y = myNeuralNetworkFunction(x);
if (false)
% Generate a Simulink diagram for simulation or deployment with.
% Simulink Coder tools.

Best Answer

Standardize variables to zero mean and unit variance using ZSCORE.
help zsore
doc zscore
Good designs will have MSE < 1/100
For examples search NEWSGROUP and ANSWERS using
greg zscore
Hope this helps.
Thank you for formally accepting my answer