[Rcpp-devel] passing function
Siddhartha Chib
chib at wustl.edu
Wed Jan 26 16:23:34 CET 2011
Thanks.
I did not understand this code
# C++ source code to operate on function and vector
cpp<- '
int n = as<int>(N);
NumericVector numvec(xvec) ;
Function f(fun) ;
for( int i=0; i<n; i++){
numvec = f( numvec ) ;
}
return numvec ;
I see that f is a Function object but what is fun? And why the looping over numvec rather than elements of numvec? Finally, how to use RcppArmadillo to do the C++ computations on the R function?
Best.
On 1/25/2011 12:17 PM, Dirk Eddelbuettel wrote:
> On 25 January 2011 at 12:01, Siddhartha Chib wrote:
> | Is it possible to pass a user defined function
> | written in R for use in rccparma. For example, is it possible to have a
>
> (What is rccparma?)
>
> | function
> | SEXP myfunction(SEXP g, SEXP a)
> | where g is a function object and a is a
> | matrix, the argument of g?
>
> Have you looked at
>
> examples/functionCallback/newApiExample.r
>
> which installed with your copy of Rcpp -- it uses Rcpp to sweep a
> user-supplied R function over a vector. Doing this with a matrix is close.
>
> And just for completeness, there is more in other place; my RcppDE riff on
> the the DEoptim software allows you to pass objective functions as either R
> or C++ functions; the C++ side then needs external pointers.
>
> Hope this helps, Dirk
>
>
--
Siddhartha Chib
Harry C. Hartkopf Professor of Econometrics and Statistics
Olin Business School, Campus Box 1133
Washington University in St. Louis
1 Brookings Dr
St. Louis, MO 63130
(314) 935-4657; (314) 935-6359 [Fax]
chib at wustl.edu
http://www.olin.wustl.edu/faculty/chib/
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