[R] CVnn2 + nnet question

[Prof Brian Ripley]

I have no idea what you are actually doing. When I run the code in the
book the output begins

fold 1
  size = 6 decay = 0.001
  inner fold 1 2 3 4 5

and those are the default values.  You *have* altered something, and it is
not reasonable to expect R-help readers to debug your code (especially not
for a commercial user).


On Mon, 14 Jun 2004, Manoj - Hachibushu Capital wrote:

> Thanks for the prompt reply. I don't think I am using any non default
> arguments but still...here is the exact syntax for two different case
> (skip = T and default) and the corresponding error message that I
> receive.
> 
> 
> Default Case ("skip = F")
> 
> Syntax	: nn.test	<-
> CVnn2(Y~X1+X2+X3+X4+X5+X6+X7+X8+X9+X10+X11,all.data.norm[1:train.set,],m
> axit=500,nreps=10)
> 
> Error message: 
> 	Fold 1
> 		Size = 0 decay = 0
> 		Inner fold 1Error in nnet.default(x,y,w.....)  : No
> weights to fit.
> 
> 
> 
> Case where Skip = T:
> 
> Syntax:	nn.test <-
> CVnn2(Y~X1+X2+X3+X4+X5+X6+X7+X8+X9+X10+X11,all.data.norm[1:train.set,],m
> axit=500,nreps=10,skip=T)
> 
> Error message:
> 	Fold 1 
> 	Size=0 decay = 0
> 	Inner fold 1Error in switch(type,raw=z,class= { : inappropriate
> fit for class
> 
> 
> Manoj 	
> 
> -----Original Message-----
> From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk] 
> Sent: Monday, June 14, 2004 8:26 PM
> To: Manoj - Hachibushu Capital
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] CVnn2 + nnet question
> 
> You are trying to fit a neural network with no connections.  That makes
> no 
> sense unless skip=T (as on the page you are quoting).
> 
> On Mon, 14 Jun 2004, Manoj - Hachibushu Capital wrote:
> 
> > Hi,
> > 	I am trying to determine the number of units in the hidden layer
> > and the decay rate using the CVnn2 script found in MASS directory
> > (reference: pg 348,MASS-4). 
> > 
> > 	The model that I am using is in the form of Y ~ X1 + X2 + X3...
> > + X11 and the underlying data is time-series in nature.
> > 
> > 	I found the MASS and nnet package extremely useful (many thanks
> > to the contributors). 
> 
> `contributors'?  Do see the DESCRIPTION file: it is hardly anonymous
> work.
> 
> > 	However I am getting an error while using the CVnn2
> > function...it says 
> 
> You have not shown us the call you used, but the default arguments are
> size = rep(6, 2), lambda = c(0.001, 0.01) so you have used non-default 
> args without telling us what.
> 
> > Fold 1 
> > Size = 0, decay = 0, inner fold 1 Error in nnet.default(x,y,w,....):
> No
> > weights  to fit.
> > 
> > 	Obliviously I am doing something wrong but am not able to figure
> > it out. 
> 
> Please do re-read the basic description of neural nets and nnet().
> 
> > Do I have pass any weights?  I am bit confused since the
> > documentation of nnet suggests says "Wts: initial parameter vector. If
> > missing chosen at Random". Has anybody faced the same error? I am
> using
> > the latest R version on Linux box. 
> 
> 

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595