all_ones_sequence bitsize function

[xuzhouchuan]

Hi，bro： I am reading the code of pef；when I see the bitsize compute, I think the function of all_ones_sequence:bitsize return 0 makes optimal_partition has 0 windows. the code like this:

//all_ones_sequence.hpp
    struct all_ones_sequence {

        inline static uint64_t
        bitsize(global_parameters const& /* params */, uint64_t universe, uint64_t n)
        {
            return (universe == n) ? 0 : uint64_t(-1);
        }

//optimal_partition.hpp
        // create the required window: one for each power of approx_factor
        std::vector<cost_window<ForwardIterator>> windows;
        cost_t cost_lb = cost_fun(1, 1);  // minimum cost
        cost_t cost_bound = cost_lb;
        while (eps1 == 0 || cost_bound < cost_lb / eps1) {
            windows.emplace_back(begin, cost_bound);
            if (cost_bound >= single_block_cost)
                break;
            cost_bound = cost_bound * (1 + eps2);
        }

the cost_fun is this:

    static DS2I_FLATTEN_FUNC uint64_t bitsize(global_parameters const& params,
                                              uint64_t universe, uint64_t n) {
        uint64_t best_cost = all_ones_sequence::bitsize(params, universe, n);

        uint64_t ef_cost =
            compact_elias_fano::bitsize(params, universe, n) + type_bits;
        if (ef_cost < best_cost) {
            best_cost = ef_cost;
        }

        uint64_t rb_cost =
            compact_ranked_bitvector::bitsize(params, universe, n) + type_bits;
        if (rb_cost < best_cost) {
            best_cost = rb_cost;
        }

        return best_cost;
    }

whereas I misunderstand by the code, i'm glad to know what works here？0 windows?

[xuzhouchuan]

And I see the Java version of this cost_fn returns 128 fixed size(for all ones)，the code is not the latest or some other reasons？