auto v_a = std::array<std::array<double, 5>, 5>{{
            { 6.80, -6.05, -0.45,  8.32, -9.67},
            {-2.11, -3.30,  2.58,  2.71, -5.14},
            { 5.66,  5.36, -2.70,  4.35, -7.26},
            { 5.97, -4.44,  0.27, -7.17,  6.08},
            { 8.23,  1.08,  9.04,  2.14, -6.87}
        }};
        auto v_b = std::array<double, 5>
            {4.02,  6.19, -8.22, -7.57, -3.03};
        auto ga = std::array<std::array<double, 5>, 5>{{
            {v_a[0][0], v_a[0][1], v_a[0][2], v_a[0][3], v_a[0][4]},
            {v_a[1][0], v_a[1][1], v_a[1][2], v_a[1][3], v_a[1][4]},
            {v_a[2][0], v_a[2][1], v_a[2][2], v_a[2][3], v_a[2][4]},
            {v_a[3][0], v_a[3][1], v_a[3][2], v_a[3][3], v_a[3][4]},
            {v_a[4][0], v_a[4][1], v_a[4][2], v_a[4][3], v_a[4][4]}
        }};
        auto gb = std::array<double, 5>
            {v_b[0], v_b[1], v_b[2], v_b[3], v_b[4]};

void clobber(double value) {
    for(int i=0;i<5;i++) { for(int j=0;j<5;j++)  {ga[i][j]+=value;} gb[i] -= value; }
}

int main(int argc, char** argv) {
    int value = argc>1? atoi(argv[1]):0;
    auto sum_x = std::array<double, 5> {0., 0., 0., 0., 0.};
    for(auto i = 0u; i < 1000 * 1000; ++i){
        if(argc>1) clobber(value);
        const auto a = ga;
        const auto b = gb;
        auto x = std::array<double, 5> {};
        linear_equations::semi_static::solve<5>(a, b, x);

        for(auto j = 0u; j < 5; ++j)
            sum_x[j] += x[j];
    }
    std::cout << sum_x[0] << ' ' << sum_x[1] << ' '
        << sum_x[2] << ' ' << sum_x[3] << ' ' << sum_x[4] << '\n';
    return 0;
}