Function meshgrid

source/matplot/util/common.cpp:486–497

    }

    std::pair<vector_2d, vector_2d> meshgrid(const vector_1d &x,
                                             const vector_1d &y) {
        vector_2d X(y.size(), std::vector<double>(x.size(), 0));
        vector_2d Y(y.size(), std::vector<double>(x.size(), 0));
        for (size_t i = 0; i < y.size(); ++i) {
            for (size_t j = 0; j < x.size(); ++j) {
                X[i][j] = x[j];
                Y[i][j] = y[i];
            }
        }
        return std::make_pair(X, Y);
    }

    std::pair<vector_2d, vector_2d> meshgrid(const vector_1d &x_and_y) {
        return meshgrid(x_and_y, x_and_y);