#define _USE_MATH_DEFINES

#include <iostream>

#include <cmath>

#include <matplotlibcpp.h>

#include <vector>

#include <xtensor/xbuilder.hpp>

#include <xtensor/xtensor.hpp>

namespace plt = matplotlibcpp;

std::vector<double> get_yv(std::size_t len) {

std::vector<double> res(len);

for (std::size_t i = 0; i < len; ++i) {

res[i] = i*i + 2;

}

return res;

}

template <class E>

auto get_fy(E&& e) {

auto res = e + 2.0;

return std::move(res);

}

int main(int argc, char **argv) {

std::size_t len = 10;

/***** vectors *****/

std::vector<double> xv(len), yv(len);

for (std::size_t i = 0; i < len; ++i) {

xv[i] = i;

yv[i] = i*i;

}

plt::named_plot("vector - lvalue", xv, yv);

plt::named_plot("vector - rvalue", xv, get_yv(len));

/***** xtensors *****/

xt::xtensor<double, 1> xx = xt::linspace<double>(0, len-1, len);

xt::xtensor<double, 1> xy = xt::square(xx) + 4;

plt::named_plot("xtensor - lvalue", xx, xy, "--");

plt::named_plot("xtensor - rvalue", xx, xy+1, "--");

/***** xfunction*****/

auto fx = xt::linspace<double>(0, len-1, len);

auto fy = xt::square(xx) + 6;

plt::named_plot("xfunction - lvalue", fx, fy, "-.");

plt::named_plot("xfunction - rvalue", fx, get_fy(fy), "--");

plt::legend();

plt::show();

return 0;

}