On Tue, 13 Sep 2005, nwew wrote:
> Dear R-developers,
>
> Using .Call I pass a S4 class with e.g. the following class definition:
>
> setClass("mmatrix",representation(
> data="matrix")
> )
>
> On the "C side" i do
> mat = GET_SLOT(vs,install("data"));
> and then:
> printf("%f\n",NUMERIC_POINTER(mat)[1]);
>
>
> The above print statement produces the correct output if
> xx<- new("mmatrix")
> [EMAIL PROTECTED]<-matrix(1:12+0.1,3,4). (data is double)
>
> However it prints
> 0.0000
> if [EMAIL PROTECTED] are integers ( [EMAIL PROTECTED]<-matrix(1:12,3,4) ).
>
> Can anyone explain it to me why?
> I thought that NUMERIC_POINTER makes it clear that i expect datatype numeric.
> (Why otherwise the distinction with INTEGER_POINTER)
No, I think you have to make sure that the bits are in the correct mode.
Could you use validation at the new() to do it? A matrix could be double,
integer, logical or character at least, but on the C side you only want
double. I don't think expectations come into it.
Roger
>
>
> cheers
> Eryk
>
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--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: [EMAIL PROTECTED]
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