Hello,

Thanks for that. I've taken a look at the source code, and I see that

the bulk of the processing is done in C, with R acting as a wrapper.

Below is the function I think is doing the training in the network.

I'm guessing it's the standard Backpropagation with a decay term

algorithm? Can anyone confirm if that's correct?

Cheers,

Wee-Jin

------------------------------------------------------------

void

VR_dfunc(double *p, double *df, double *fp)

{

int i, j;

double sum1;

for (i = 0; i < Nweights; i++)

wts[i] = p[i];

for (j = 0; j < Nweights; j++)

Slopes[j] = 2 * Decay[j] * wts[j];

TotalError = 0.0;

for (i = 0; i < NTrain; i++) {

for (j = 0; j < Noutputs; j++)

toutputs[j] = TrainOut[i + NTrain * j];

fpass(TrainIn + i, toutputs, Weights[i], NTrain);

bpass(toutputs, Weights[i]);

}

sum1 = 0.0;

for (i = 0; i < Nweights; i++)

sum1 += Decay[i] * p[i] * p[i];

*fp = TotalError + sum1;

for (j = 0; j < Nweights; j++)

df[j] = Slopes[j];

Epoch++;

}

-----------------------------------------

On 23 Nov 2006, at 07:36, Dieter Menne wrote:

> Wee-Jin Goh <wjgoh <at> brookes.ac.uk> writes:

>

>>

>> Just to add to this, I also need to know what language is the "nnet"

>> package written in? Is it in pure R or is it a wrapper for a C

>> library.

>

> As usual, you can download the full source to find out what you

> want, but it's a

> bit hidden. Simply said, nnet (R+C) is part of package MASS is part

> of bundle

> VR, and can be downloaded as a tar.gz from

>

>

http://cran.at.r-project.org/src/contrib/Descriptions/VR.html>

> (No private flames, please, in case I should have mixed up package

> and bundle).

>

> /* nnet/nnet.c by W. N. Venables and B. D. Ripley Copyright (C)

> 1992-2002

> *

> * weights are stored in order of their destination unit.

> * the array Conn gives the source unit for the weight (0 = bias unit)

> * the array Nconn gives the number of first weight connecting to

> each unit,

> * so the weights connecting to unit i are Nconn[i] ... Nconn[i+1]

> - 1.

> *

> */

>

> #include <R.h>

> #include <R_ext/Applic.h>

>

> ______________________________________________

>

[hidden email] mailing list

>

https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide

http://www.R-project.org/posting-
> guide.html

> and provide commented, minimal, self-contained, reproducible code.

[[alternative HTML version deleted]]

______________________________________________

[hidden email] mailing list

https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide

http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.