[Rcpp-devel] Range constructor and memory allocation

Gregor Kastner gregor.kastner at wu.ac.at
Tue Feb 18 19:12:37 CET 2014

Dear all,

while writing an iterator hack for the problem encountered a few hours ago
and posted here:


I have noticed that the default behavior for the range constructor for e.g.
Rcpp::NumericVector seems to be to allocate fresh memory:

arma::mat obj1(5, 10, arma::fill::zeros);
Rcpp::NumericVector obj2(obj1.begin(), obj1.begin() + 5);
obj2 = 1.;
Rprintf("obj1: %f, obj2: %f\n", obj1(0,0), obj2(0));

yields that obj1 and obj2 differ.

Is there any way to tell the range constructor to reuse existing memory
similarly to the (Rcpp)Armadillo feature copy_aux_mem = false or am I
missing something more subtle?

Thanks in advance for any hints,

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