Date: Aug 13, 2010 8:20 PM
Author: Greg Heath
Subject: Re: Neural Networks weights and bias help
On Aug 13, 10:47 am, "hasan batuk" <kapadokya...@yahoo.com> wrote:

> Hi, i am trying to learn NN toolbox. I tried to creat a networks that multiply the number by 3 and gives as output. For simplicity, i made the transfer function also linear. It works well but i tried to reach the same result by using the bias and weight values.

> x -> input

> y-> output

>

> a= [ (w1*x + b1) * w2 ]+b2

>

> but it ends up with same as the input value. I am really confused about it. it looks very simple but i couldnt find what i miss. Thanks for your time. the code is below

>

> P=[1:4:200]; % training set

> T=P*3; % target set

>

> net=newff(P,T,1);

> net.layers{1}.transferFcn = 'purelin'; % making transfer func. as linear

Can include this in the previous command.

> net=train(net,P,T);

>

> y=sim(net,101) % giving a number say 101 as an input to system and taking 303 as output as expected.

>

> % trying to reach same result by using weight and bias values. it ends up with 101, not 303.

>

> a1=(net.iw{1,1}*101)+net.b{1}; % output of first layer

>

> a2=(net.lw{2,1}*a1)+net.b{2} % output of second layer

help newff

Carefully read the explanations of IPF and OPF

Hope this helps.

Greg