how to predict from a trained neural network ?

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

Answer 1

[Greg Heath]

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)

Hope this helps.

Greg

Answer 2

[Mritula C]

Hi How do you predicted with a new test class?

[Greg Heath]

1. You misplaced your commented question into an Answer Box.
2. This is a regression prolem. Your question involves classification.

Greg