Function measure_random_access

src/benchmarks/packed_vector.cpp:30–63

template <std::size_t num_rounds, std::size_t num_entries, typename VectorT>
auto measure_random_access()
{
    std::vector<std::size_t> indices(num_entries);
    std::iota(indices.begin(), indices.end(), 0);
    std::mt19937 g(1337);
    std::shuffle(indices.begin(), indices.end(), g);

    VectorT vector(num_entries);

    TIMER_START(write);
    for (auto round : util::irange<std::size_t>(0, num_rounds))
    {
        for (auto idx : util::irange<std::size_t>(0, num_entries))
        {
            vector[indices[idx]] = idx + round;
        }
    }
    TIMER_STOP(write);

    TIMER_START(read);
    auto sum = 0;
    for (auto round : util::irange<std::size_t>(0, num_rounds))
    {
        sum = round;
        for (auto idx : util::irange<std::size_t>(0, num_entries))
        {
            sum += vector[indices[idx]];
        }
        dont_optimize_away(sum);
    }
    TIMER_STOP(read);

    return Measurement{TIMER_MSEC(write), TIMER_MSEC(read)};
}

int main(int, char **)
{