[R] A Neural Network question

[Philip Rhoades]

People,

I thought I needed to have some familiarity with NNs for some of my 
current (non-profit, brain-related) projects so I started looking at 
various programming environments including R and I got this working:

   http://gekkoquant.com/2012/05/26/neural-networks-with-r-simple-example

however I needed pictures to help understand what was going on and then 
I found this:

   
https://jamesmccaffrey.files.wordpress.com/2012/11/backpropagationcalculations.jpg

which I thought was almost intelligible so I had an idea which I thought 
would help the learning process:

- Create a very simple NN implemented as a spreadsheet where each sheet 
would correspond to an iteration

I started doing this on LibreOffice:

- I think am already starting to get a better idea of how NNs work just 
from the stuff I have done on the spreadsheet already

- I have now transferred my LibreOffice SpreadSheet (SS) to a shared 
Google Docs Calc file and can share it for editing with others

   
https://docs.google.com/spreadsheets/d/1eSCgGU5qeI3_PmQhwZn4RH0NznUekVP5BP7w4MpKSUc/pub?output=pdf

- I think I have the SS calculations correct so far except for the stuff 
in the dashed purple box in the diagram

- I am not sure how to implement the purple box . . so I thought I would 
ask for help on this mailing list

If someone can help me with the last bit of the SS, from there I think I 
can then repeat the FR and BP sheets and see how the Diffs evolve . .

Is anyone interested in helping to get this last bit of the spreadsheet 
working so I can move on to doing actual work with the R packages with 
better understanding?

Thanks,

Phil.
-- 
Philip Rhoades

PO Box 896
Cowra  NSW  2794
Australia
E-mail:  phil at pricom.com.au