dlib C++ Library - checkerboard.h

    #ifndef DLIB_CHECKERBOARD_TeST_H_
    #define DLIB_CHECKERBOARD_TeST_H_

    #include <dlib/matrix.h>
    #include <vector>
    #include <dlib/rand.h>

    namespace dlib
    {

        template <typename scalar_type>
        void get_checkerboard_problem (
            std::vector<matrix<scalar_type,2,1> >& x,
            std::vector<scalar_type>& y,
            const long num_samples,
            const long board_dimension = 8
        )
        /*!
            requires
                - num_samples > 0
                - board_dimension > 0
            ensures
                - #x.size() == y.size() == num_samples
                - is_binary_classification_problem(#x,#y) == true
                - #x will contain points and #y labels that were
                  sampled randomly from a checkers board that has
                  board_dimension squares on each side.
        !*/
        {
            static dlib::rand::float_1a rnd;

            x.clear();
            y.clear();

            matrix<scalar_type,2,1> sample;
            for (long i = 0; i < num_samples; ++i)
            {
                sample(0) = rnd.get_random_double();
                sample(1) = rnd.get_random_double();
                sample *= board_dimension;

                x.push_back(sample);
                if (((int)sum(floor(sample)) %2) == 0)
                    y.push_back(+1);
                else
                    y.push_back(-1);

            }
        }

    }

    #endif // DLIB_CHECKERBOARD_TeST_H_