[bug](sindi): range search return repeated results #2669

Affected area

sindi

Interface

cpp

VSAG version

v0.18.8

Summary

range search on sindi return repeated results

Minimal reproducer

vsag::Resource resource;
vsag::Engine engine(&resource);
const std::string build_params = R"({
"dtype": "sparse",
"dim": 3,
"metric_type": "ip",
"index_param": {
"use_reorder": true,
"term_id_limit": 4000,
"doc_prune_ratio": 0,
"window_size": 60000,
"use_quantization": false
}
})";
auto create_result = engine.CreateIndex("sindi", build_params);
auto index = create_result.value();

std::vector<std::vector<uint32_t>> indices = {
{5, 100, 2000}, {5, 50, 2000}, {10, 100, 3000}};
std::vector<std::vector> values = {
{0.5f, 0.8f, 0.6f}, {0.3f, 0.9f, 0.1f}, {0.7f, 0.4f, 0.5f}};
std::vector<int64_t> ids = {1, 2, 3};
for (size_t i = 0; i < ids.size(); ++i) {
vsag::SparseVector sparse_vector;
sparse_vector.len_ = static_cast<uint32_t>(indices[i].size());
sparse_vector.ids_ = indices[i].data();
sparse_vector.vals_ = values[i].data();
auto dataset = vsag::Dataset::Make();
dataset->NumElements(1)
->Ids(&ids[i])
->SparseVectors(&sparse_vector)
->Owner(false);
auto add_result = index->Add(dataset);
}

vsag::SparseVector query_vector;
query_vector.len_ = static_cast<uint32_t>(indices[0].size());
query_vector.ids_ = indices[0].data();
query_vector.vals_ = values[0].data();
auto query = vsag::Dataset::Make();
query->NumElements(1)->SparseVectors(&query_vector)->Owner(false);
const std::string search_params =
R"({"sindi": {"query_prune_ratio": 0, "n_candidate": 100}})";
auto range_result =
index->RangeSearch(query, 1.0f, search_params, /limited_size=/-1);

auto result = range_result.value();
for (int64_t i = 0; i < result->GetDim(); ++i) {
std::cout << "id: " << result->GetIds()[i]
<< ", distance: " << result->GetDistances()[i] << '\n';
}

Environment

- OS: Alibaba Cloud Linux 3
- vsag version: v0.18.8
- compiler version: c++ (GCC) 10.2.1 20200825 (Alibaba 10.2.1-3.9 2.32)

Expected behavior

return unique results

Actual behavior

References

No response

Additional context

No response