how to predict from a trained neural network ?

Question

Hello I am trying to use neural network to make some prediction based on my input and target data. I have read all related tutorial in Matlab and also looked at the matlab examples. I kinda learned how to develop a network but I dont know how to use this train network to make some prediction ? is there any code that im missing ? does anyone have a sample script that can be shared here? that's what I have, for example : x=[1 2 3;4 5 3] t=[0.5 0.6 0.7] , net=feedforwardnet(10) , net=train(net,x,t) , perf=perform(net,y,t) how can I predict the output for a new set of x (xprime=[4 2 3;4 7 8]) based on this trained network? thanks

John Williams · Accepted Answer

1. Your code should yield an error because you have not defined y.
here are two ways to define output y, error e and normalized mean square error NMSE (= 1-Rsquare)
 
 1. [ net tr ] = train(net,x,t);
           y   = net(x);
           e   = t-y;

 2. [ net tr y e ] = train(net,x,t);  % My favorite
then, in general,
    NMSE = mse(e)/mean(var(t',1))
or for 1-dimensional outputs
   NMSE =  mse(e)/var(t,1)

how to predict from a trained neural network ?

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