Get error "Aborted (core dumped)" when deleting an ID from IVF + PQ with an IndexIDMap2 wrapper

[huutuanuet]

Hello,
In C++17, with faiss 1.11.0, environment Raspberry Pi4, I have the following schema:

1. Config:
   "dimension": 768,
   "metric": INNER_PRODUCT,
   "ivf": {
   "nlist": 2048,
   "nprobe": 32
   },
   "pq": {
   "m": 96,
   "nbits": 8
   },

2. Source code:
   a. Create Index
   auto quantizer = std::make_unique<faiss::IndexFlat>(config.dimension, metric);
   auto ivf_index =
   std::make_unique<faiss::IndexIVFPQ>(quantizer.release(), config.dimension, ncentroids, m, nbits, metric);
   ivf_index->nprobe = nprobe;
   auto idmap_index = std::make_unique<faiss::IndexIDMap2>(ivf_index.release());
   b. Add_with_ids
   std::vector<float> processed_vector = embedding;
   if (config.metric == MetricType::COSINE) {
   processed_vector = NormalizeVector(embedding);
   }
   index->add_with_ids(1, processed_vector.data(), &custom_id);
   c. Remove_ids
   Input parameter: const std::vector<int64_t>& faiss_ids
   // Create ID selector for the IDs to remove
   faiss::IDSelectorBatch selector(faiss_ids.size(), faiss_ids.data());
   // Remove vectors using remove_ids
   size_t removed = index->remove_ids(selector);

3. Step to reprocedure
   Step 1: I add a data set including 10 vectors, now the ID will be ID[1...10]
   Step 2: I delete ID 1, the program says delete successful.
   Step 3: I delete ID 2, the program will crash immediately.
   Error log:
   Faiss assertion 'j == index->ntotal' failed in virtual size_t faiss::IndexIDMapTemplatefaiss::Index::remove_ids(const IDSelector &) [IndexT = faiss::Index] at /usr/src/debug/faiss/1.11.0/faiss/IndexIDMap.cpp:197
   Aborted (core dumped)

I found the same error message, but the cause is different, can not apply the fix in the article.
#4535

You can see the pictures to visualize what I mean better. I am new to this field so the terminology used may not be accurate.

[huutuanuet]

Since IndexIVFFlat and IndexIVFPQ already have add_with_ids() and remove_ids, there is no need to wrap with IndexIDMap2.
After unwarping with IndexIDMap2, the error no longer occurs.