[Rd] Namespaces, coercion and setAs

[roger koenker]

Absolutely correct.  Adding coerce to the NAMESPACE list of 
exportMethods
resolves the problem.  Leaves only the mildly mysterious

Undocumented S4 methods:
   generic coerce and siglist numeric,matrix.diag.csr
All user-level objects in a package (including S4 classes and methods)
should have documentation entries.

to clean up.  Thanks very much!!

Roger

On Nov 26, 2004, at 12:29 PM, Roger Bivand wrote:

> 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 at uiuc.edu			Department of Economics
>> vox: 	217-333-4558				University of Illinois
>> fax:   	217-244-6678				Champaign, IL 61820
>>
>> ______________________________________________
>> R-devel at 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 at nhh.no
>