R devel - Nov 2004 - Namespaces, coercion and setAs

I'm trying to resolve a small problem that has arisen from introducing a
NAMESPACE for the package SparseM.  Prior to the namespace I had
a class "matrix.diag.csr" that consisted of diagonal sparse matrices.
It
was defined to have the same attributes as the matrix.csr class and 
setAs
was used to define how to coerce integers and vectors into this form:

setClass("matrix.diag.csr","matrix.csr")

setAs("numeric","matrix.diag.csr",function(from){
         if(length(from)==1){
                 n <- as.integer(from)
                 if(n>0) from  <-  rep(1,n)
                 else stop("Sparse identity matrices must have positive, 
integer dimension")
                 }
         else n <- length(from)
         return(new("matrix.diag.csr", ra = from ,ja =
as.integer(1:n),
                 ia = as.integer(1:(n+1)), dimension = 
as.integer(c(n,n))))
         })

This seemed to be fine.   I could do,

	A  <- as(5,"matrix.diag.csr")

and A would be a 5x5 identity matrix in sparse form.  But post-namespace
I get:

 >A <-  as(5,"matrix.diag.csr")
Error in as(5, "matrix.diag.csr") : No method or default for coercing 
"numeric" to "matrix.diag.csr"

so apparently using exportClass(matrix.diag.csr)  isn't sufficient for 
coerce to know what to do.
Using findClass("matrix.diag.csr") indicates that the class is 
recognized to be from SparseM,
so my question is:  is there some mechanism that I'm missing in the 
NAMESPACE scheme
that would enable my old setAs() directive to work, or is there some 
other suggestion on how
to proceed?


url:	www.econ.uiuc.edu/~roger        	Roger Koenker
email	rkoenker@uiuc.edu			Department of Economics
vox: 	217-333-4558				University of Illinois
fax:   	217-244-6678				Champaign, IL 61820

On Fri, 26 Nov 2004, roger koenker wrote:
> I'm trying to resolve a small problem that has arisen from introducing
a
> NAMESPACE for the package SparseM.  Prior to the namespace I had a class
> "matrix.diag.csr" that consisted of diagonal sparse matrices.  It
was
> defined to have the same attributes as the matrix.csr class and setAs
> was used to define how to coerce integers and vectors into this form:
> 
> setClass("matrix.diag.csr","matrix.csr")
> 
> setAs("numeric","matrix.diag.csr",function(from){
>          if(length(from)==1){
>                  n <- as.integer(from)
>                  if(n>0) from  <-  rep(1,n)
>                  else stop("Sparse identity matrices must have
positive,
> integer dimension")
>                  }
>          else n <- length(from)
>          return(new("matrix.diag.csr", ra = from ,ja =
as.integer(1:n),
>                  ia = as.integer(1:(n+1)), dimension = 
> as.integer(c(n,n))))
>          })
> 
> This seemed to be fine.   I could do,
> 
> 	A  <- as(5,"matrix.diag.csr")
> 
> and A would be a 5x5 identity matrix in sparse form.  But post-namespace
> I get:
> 
>  >A <- as(5,"matrix.diag.csr") Error in as(5,
"matrix.diag.csr") : No
> method or default for coercing "numeric" to
"matrix.diag.csr"
> 
> so apparently using exportClass(matrix.diag.csr)  isn't sufficient for
> coerce to know what to do. Using findClass("matrix.diag.csr")
indicates
> that the class is recognized to be from SparseM, so my question is:  is
> there some mechanism that I'm missing in the NAMESPACE scheme that
would
> enable my old setAs() directive to work, or is there some other
> suggestion on how to proceed?
I'm far from sure about this, but is "coerce" one of the exported
methods?
I'm having the same difficulty in retrofitting a NAMESPACE to the 
forthcoming sp package of spatial classes, for S4 classes. 

I see from src/library/methods/NAMESPACE that as and coerce are exported 
from there - should a package with a NAMESPACE and S4 classes do 

import(methods) ?

Roger
> 
> 
> url:	www.econ.uiuc.edu/~roger        	Roger Koenker
> email	rkoenker@uiuc.edu			Department of Economics
> vox: 	217-333-4558				University of Illinois
> fax:   	217-244-6678				Champaign, IL 61820
> 
> ______________________________________________
> R-devel@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
> 
-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand@nhh.no