[R] lattice add a fit

[David Winsemius]

On Oct 7, 2014, at 9:15 PM, Duncan Mackay wrote:

I'm a tad puzzled by the comments about needing to build a panel function for locfit. The various plot.locfit functions are actually lattice calls. 

locfit:::panel.locfit  # already exists, and even has versions for 1d, 2d and 3d purposes.

And there is a llines.locfit function that will add locfit smooths to existing lattice plots.

It's a very simple function and could easily be modified to any regression method that has a predict functions:

> locfit:::llines.locfit
function (x, m = 100, tr = x$trans, ...) 
{
    newx <- lfmarg(x, m = m)[[1]]  # probably need to modify to your purposes
    y <- predict(x, newx, tr = tr)
    llines(newx, y, ...)
}
<environment: namespace:locfit>

-- 
David

> 
> You will have to make your own panel function for locfit if you want to use
> it
> I have done it in the past - read the help for 
> library(locfit)
> ?plot.locfit 
> and the links
> ?lattice::prepanel
> 
> Regards
> 
> Duncan
> 
> Duncan Mackay
> Department of Agronomy and Soil Science
> University of New England
> Armidale NSW 2351
> Email: home: mackay at northnet.com.au
> 
> 
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
> Behalf Of Bond, Stephen
> Sent: Tuesday, 7 October 2014 23:02
> To: r-help at R-project.org
> Subject: [R] lattice add a fit
> 
> What is the way to add an arbitrary fit from a model to a lattice
> conditioning plot ?
> 
> For example
> xyplot(v1 ~v2 | v3,data=mydata,
>        panel=function(...){
>            panel.xyplot(...)
>            panel.loess(...,col.line="red")
>        }
> )
> Will add a loess smoother. Instead, I want to put a fit from lm (but not a
> simple straight line) and the fit has to be done for each panel separately,
> not one fit for the full data set, so sth like an lm equivalent of
> panel.locfit (there is no panel.lmfit)
> Thank you.
> 
> Stephen B
> 
> 
> 	[[alternative HTML version deleted]]
> 


David Winsemius
Alameda, CA, USA