extern "C" SEXP c_rthgini(SEXP x, SEXP mu, SEXP unbiased_, SEXP nthreads)
{
const int unbiased = INTEGER(unbiased_)[0];
const int n = LENGTH(x);
SEXP gini;
PROTECT(gini = allocVector(REALSXP, 1));
RTH_GEN_NTHREADS(nthreads);
thrust::device_vector<double> dx(REAL(x), REAL(x)+n);
thrust::sort(dx.begin(), dx.end());
thrust::counting_iterator<int> begin(0);
thrust::counting_iterator<int> end = begin + n;
thrust::plus<flouble> binop;
DBL(gini) = (double) thrust::transform_reduce(begin, end, compute_gini(n, dx.begin()), (flouble) 0., binop);
if (unbiased)
DBL(gini) = DBL(gini) / (n*(n-1)*DBL(mu));
else
DBL(gini) = DBL(gini) / (n*n*DBL(mu));
return gini;
}
RcppExport SEXP rthgini(SEXP x_, SEXP mu_, SEXP unbiased_, SEXP nthreads)
{
Rcpp::NumericVector x(x_);
Rcpp::NumericVector mu(mu_);
const int unbiased = INTEGER(unbiased_)[0];
const int n = LENGTH(x);
Rcpp::NumericVector gini(1);
#if RTH_OMP
omp_set_num_threads(INT(nthreads));
#elif RTH_TBB
tbb::task_scheduler_init init(INT(nthreads));
#endif
thrust::device_vector<double> dx(x.begin(), x.end());
thrust::sort(dx.begin(), dx.end());
thrust::counting_iterator<int> begin(0);
thrust::counting_iterator<int> end = begin + n;
thrust::plus<flouble> binop;
gini[0] = (double) thrust::transform_reduce(begin, end, compute_gini(n, dx.begin()), (flouble) 0., binop);
if (unbiased)
gini[0] = gini[0]/n/(n-1)/mu[0];
else
gini[0] = gini[0]/n/n/mu[0];
return gini;
}
