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//
// R package splines2 by Wenjie Wang and Jun Yan
// Copyright (C) 2016-2021
//
// This file is part of the R package splines2.
//
// The R package splines2 is free software: You can redistribute it and/or
// modify it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or any later
// version (at your option). See the GNU General Public License at
// <https://www.gnu.org/licenses/> for details.
//
// The R package splines2 is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
//
#include <RcppArmadillo.h>
// [[Rcpp::plugins(cpp11)]]
#include <splines2Armadillo.h>
// [[Rcpp::export]]
Rcpp::NumericMatrix rcpp_naturalSpline(
const arma::vec& x,
const unsigned int df,
const arma::vec& internal_knots,
const arma::vec& boundary_knots,
const unsigned int derivs = 0,
const bool integral = false,
const bool complete_basis = true
)
{
splines2::NaturalSpline ns_obj;
// if df > 0 and knots are not specified
// auto set internal knots based on df
if (df > 0 && internal_knots.n_elem == 0) {
// compute actual spline degree of freedom
const unsigned int wo_intercept {
static_cast<unsigned int>(! complete_basis)
};
unsigned int spline_df { df + wo_intercept };
ns_obj = splines2::NaturalSpline(x, spline_df, boundary_knots);
} else {
// else ignore df
ns_obj = splines2::NaturalSpline(x, internal_knots, boundary_knots);
}
Rcpp::NumericMatrix out;
// 1) basis, 2) derivative, or 3) integral
if (integral && derivs == 0) {
// integrals
out = splines2::arma2rmat(ns_obj.integral(complete_basis));
} else if ((! integral && derivs == 0) || (integral && derivs == 1)) {
// bases
out = splines2::arma2rmat(ns_obj.basis(complete_basis));
} else {
// derivatives
out = splines2::arma2rmat(
ns_obj.derivative(derivs - static_cast<unsigned int>(integral),
complete_basis)
);
}
// add attributes
out.attr("dimnames") = Rcpp::List::create(
R_NilValue, splines2::char_seq_len(out.ncol())
);
out.attr("x") = splines2::arma2rvec(x);
out.attr("knots") = splines2::arma2rvec(ns_obj.get_internal_knots());
out.attr("Boundary.knots") =
splines2::arma2rvec(ns_obj.get_boundary_knots());
out.attr("derivs") = static_cast<int>(derivs);
out.attr("integral") = integral;
out.attr("intercept") = complete_basis;
return out;
}
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