Le 14/11/12 14:05, Christian Gunning a écrit :
Dear all,
The attached file is for inclusion in RcppArmadillo/src. It's a
templated implementation of R's sample that relies on a few Armadillo
functions. It should produce results identical to R, except when R uses
Walker's alias method (with replacement, more than 200 nonzero
probabilities given).
This is intended to be used solely in C++ code, and is not exported.
best,
Christian
University of New Mexico
--
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Interesting. With some more work, we could even make this sugary. i.e.
have this signature:
template <int RTYPE, bool NA, typename T>
Rcpp::Vector<RTYPE> sample(const Rcpp::VectorBase<RTYPE,NA,T> &x, const
int size, const bool replace, NumericVector prob_ = NumericVector(0) ) {
typedef Rcpp::Vector<RTYPE> TARGET ;
// Templated sample -- should work on any Rcpp Vector
int ii, jj;
int nOrig = x.size();
int probsize = prob_.size();
// Create return object
TARGET ret(size);
if ( size > nOrig && !replace) throw std::range_error( "Tried to sample
more elements than in x without replacement" ) ;
...
}
So that we could sample sugar expressions :-)
Romain
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