A simple non-linear neuron model

Hello everyone,

though delayed (thanks to *indows), here comes my neuron model article. First of all, I want to make clear that none of these can be treated as a 100% truth. There may be mistakes everywhere…

Some bibliography

There is a very good intro to neural networks theory written by some other WordPress blogger. It can be found here.

There is also a great book in Polish, available on-line – by the master and pioneer of Neural Networks in Poland – prof. Tadeusiewicz, available here, which I wholeheartedly recommend.

About this source code

This is for those who want to learn how to create neural networks but never came across a simple example – for people like me. You get a lot of full-sized neural networks source code available on-line, whole C++ ANN libraries GPL-licensed, but never anything for a simple human being to start with. So I decided it was a high time to change that. From now on, I’ll keep posting NN-related source code, increasing its level of complicatedness. The examples will be based on the programs that come along with the book written by Tadeusiewicz. Those programs were written in QBASIC, which is rather ancient. So i’ll kind of port them to C++.

Source code itself…

can be found here. It’s not complete and idiot-proof so if you want to prove it’s not working, you can easily The idea is that you can characterize a flowe by two traits – it can smell good (or bad) and it can be colourfull. Those two traits can be assessed with a value ranging (for example) from -5 to 5. So you can teach the neuron to like flowers which smell very well (4-5) and are quite colourfull (2-3) and after few rounds (7 is usually enough) it can discern well those from the others and tell you how much it likes such flowers.. A pretty straightforward example but it should suffice to illustrate a simple neuron.

The neuron

is non-linear with activation function being f(x) = 1/(1 – exp(-x)). Its derivative is f(x)*(1-f(x)). Well, I guess you’ll get the rest from the source code. If not, comment and ask

Have fun,

dare2be

Tags: books, neural network, tadeusiewicz