[Rcpp-devel] Using Armadillo objects as arguments in calls to R
Romain Francois
romain.francois at dbmail.com
Tue May 11 22:25:09 CEST 2010
Thanks for letting us know of the problem ... and the solution
Not sure what the problem is. The _["x"] = is intended for implicit
calls to wrap, but it should not trouble you if you make them explicit.
maybe we did not handle properly the special case where the rhs is
already a SEXP.
Will have a look when I get a chance.
Thanks.
Romain
Le 11/05/10 22:17, Davor Cubranic a écrit :
>
> Hmm, once I stopped using 'wrap' and just passed Armadillo objects using 'Named', I'm able to run unit tests with no errors.
>
> I.e., I now use:
>
> List data = List::create(_["x"] = x,
> _["y"] = y);
> const NumericVector out_r = predict_fn(loess_fn(formula_fn("y~x"),
> data,
> _["weights"] = weights,
> _["span"] = span));
>
> Could the issue really have been caused my using 'wrap'? What does 'wrap' do that would lead to a segfault, that I now avoid by using 'Named'?
>
> Davor
> (R 2.10.1, Rcpp 0.7.11, Armadillo 0.9.4)
>
>
> On 2010-05-11, at 12:35 PM, Davor Cubranic wrote:
>
>> Can anyone tell me about issues I have to look out for when dealing with Rcpp Functions and passing Armadillo objects as arguments? I'm getting "not compatible with INTSXP" and segfault errors when calling the following Rcpp equivalent of R's 'predict(loess(y~x, weights=w, span=span))'. The errors usually only manifest only after several dozen calls.
>>
>> Davor
>>
>>
>> const vec predict(const vec& x, const vec& y,
>> const vec& weights, const double span) {
>> Function formula_fn("formula");
>> Function loess_fn("loess");
>> Function predict_fn("predict");
>>
>> List data = List::create(_["x"] = wrap(x),
>> _["y"] = wrap(y));
>> NumericVector weights_r = wrap(weights);
>> const NumericVector out_r = predict_fn(loess_fn(formula_fn("y~x"),
>> data,
>> weights_r,
>> Named("span") = span));
>> const vec out = vec(out_r.begin(), out_r.size());
>> return out;
>> }
--
Romain Francois
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