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#include <iostream>

std::cout << "Hello derse19!" << std::endl;


    

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#include <xtensor/xio.hpp>
#include <xtensor/xarray.hpp>

xt::xarray<double> a = {{1,2,3}, {4,5,6}};

std::cout << a << std::endl;


    

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for (auto& el : a)
{
    std::cout << el << std::endl;
}


    

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a(0, 1) = 10;

std::cout << a << std::endl;


    

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std::sort(a.begin(), a.end());

std::cout << a << std::endl;


    

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std::cout << xt::transpose(a) << std::endl;


    

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a.reshape({1, 1, 6, 1});

std::cout << a << std::endl;


    

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a.reshape({2, 3});


    

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auto xfunc = sin(a) * 2;

std::cout << xfunc << std::endl;


    

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template <class T>
void print_type(T) { std::cout << __PRETTY_FUNCTION__ << std::endl; }


    

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print_type(xfunc);


    

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auto xfunc_el = xfunc(0, 1);
std::cout << xfunc_el << std::endl;


    

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xt::xarray<double> xfunc_result = xfunc;

std::cout << xfunc_result << std::endl;


    

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std::cout << a << std::endl;


    

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xt::xarray<double> brcast = {-10, +1, -10};
std::cout << brcast << std::endl;


    

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std::cout << a * brcast << std::endl;


    

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xt::xarray<double, xt::layout_type::column_major> a_cm = {{1,2,3}, {4,5,6}};

std::cout << a_cm << std::endl;


    

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// uses a std::array for shape & strides
#include <xtensor/xtensor.hpp>

xt::xtensor<double, 2> b = {{1, 2, 3}, {4, 5, 6}};
std::cout << b << std::endl;


    

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// uses a fixed size container for data (std::array)
// strides computed constexpr at compile time (no storage)
#include <xtensor/xfixed.hpp>

xt::xtensor_fixed<double, xt::xshape<2, 3>> c = {{1,2,3}, {4,5,6}};
std::cout << c << std::endl;


    

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#include <xtensor/xview.hpp>
#include <xtensor/xio.hpp>
using namespace xt::placeholders;

std::cout << a << std::endl;


    

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std::cout << xt::view(a, 1, xt::all()) << std::endl;


    

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// numpy equivalent: a[:, ::2]
std::cout << xt::view(a, xt::all(), xt::range(_, _, 2)) << std::endl;


    

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xt::view(a, xt::all(), xt::range(_, _, 2)) *= 100;

std::cout << a << std::endl;


    

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std::cout << a << std::endl;


    

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std::cout << xt::view(a, xt::keep(0, 0, 0) , xt::all()) << std::endl;


    

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#include <vector>
#include <xtensor/xadapt.hpp>

std::vector<double> vdata = {1, 2, 3, 4, 5, 6, 7, 8, 9};
auto adapted_vdata = xt::adapt(vdata, {3, 3});


    

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std::cout << adapted_vdata << std::endl;


    

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adapted_vdata(1, 2)


    

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#include <xtensor/xmath.hpp>

std::cout << sum(adapted_vdata) << std::endl;


    

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std::cout << sum(adapted_vdata, {1}) << std::endl;