Expose R function splines::splineDesign to Rcpp

expose_r_function.cpp

#include <RcppArmadillo.h>

// Expose splines::splineDesign to Rcpp
mat splineDesign_rcpp(const vec &x, const vec &knots, const int &deg)
{
    Rcpp::Environment pkg = Rcpp::Environment::namespace_env("splines");
    Rcpp::Function f = pkg["splineDesign"];
    mat y = Rcpp::as<arma::mat>(f(knots, x, deg + 1, 0, true));
    return y;
}