[R] where is "average shifted histogram"?

[Prof Brian Ripley]

On 29 Jul 2004, Peter Dalgaard wrote:

> Eckart Bindewald <eckart_bindewald at yahoo.de> writes:
> 
> > Hello!
> > In the book Modern Applied Statistics with S (4th ed),
> > section 5.6 the concept of the "average shifted
> > histogram" or ASH is mentionend. Also it is mentioned
> > in the same section "The code used is in the scripts
> > for this chapter" (from figure caption 5.8, analysis
> > of the geyser duration data).
> > *However*, I have trouble finding the code for that
> > function! Admittedly, I am a newby to R. Where exactly
> > do I find the scripts to that chapter? Commands like
> > library(MASS), or help.search("average shifted
> > histogram") did not help.
> 
> The scripts are in simple files installed with the package. So you
> need to go to the install directory and read them from there. A
> canonical way of finding it from within R is
> 
> .path.package("MASS")
> dir(file.path(.path.package("MASS"),scripts))
> file.show(file.path(.path.package("MASS"),"scripts","ch05.R"))
> 
> That being said, I couldn't off-hand spot anything ASH-like in the
> file. This might either be a difference between the R and S versions,
> or just that the remark in the figure caption does not spefically  
> relate to ASH (haven't got the book at hand just now). 

It's in the MASS3 script but not the MASS4 one.  So look in 

file.show(system.file("scripts3", "ch05.R", package = "MASS"))

at the top of section 5.6.  It is done by hand.  There is a simple 
function to do so in package ash (on CRAN), but really you should be using 
kernel methods as described in the book.

-- 
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