Forecasting product demand with neural nets

Dear MATLAB experts, I need your hlep

I'm new in MATLAB world :-) and as a beginner I have problem with my task.

I have to forecast demand for one product. I have history data for 5 years (2007 - 2011) and I have to predict demand for that product for 2012. I read the documentation and start with designing neural net. I create 2 types of neural net -- Focused Time-Delay NN and NARX. (I have data for additional factors for demand - eg. price ... and that's why I choose NARX).

My problem is>

1. Focused Time-Delay NN and NARX NN not predict. The result is simulated data for known demand. (eg. demand for 2011). If the last data for December 2011 is NaN then I get value for that. I am confused --- Is that prediction for December 2011 valid?

2. The result from Focused Time-Delay NN and NARX NN (forecast value for December 2011) is different. ( with FTDNN I get 600.000 but with NARX 460.000)

Q1: How to use time series to predict? Q2: What about different delays? Q3: Is data set enough for training and testing?

Please help me to write code for predicting

Thank you very much, I really appreciate all your effort to solve my problem

BB

Answer 1

[Greg Heath]

Search

heath NEWFFTD

for sample prediction code.

I have not used NARX yet.

Hope this helps.

Greg