removed reduction for cache_hits_per_batch variable to avoid compilation issue

      );

  }

  // Initialize vector to keep track of cache hits for each thread

  std::vector<int> cache_hits_per_thread(mapping_parameters_.num_threads, 0);

  // Initialize cache

  mm_cache mm_to_candidates_cache(mapping_parameters_.cache_size);

  mm_to_candidates_cache.SetKmerLength(kmer_size);

                                                    true,

                                                    mapping_parameters_.cache_update_param

                                                    );

          int cache_hits_for_batch = 0;

          std::fill(cache_hits_per_thread.begin(), cache_hits_per_thread.end(), 0);

          if (mapping_parameters_.debug_cache) {

            std::cout << "[DEBUG][UPDATE] update_threshold = " << history_update_threshold << std::endl;

          }

#pragma omp taskloop grainsize(grain_size) reduction(+:cache_hits_for_batch)

#pragma omp taskloop grainsize(grain_size)

          for (uint32_t pair_index = 0; pair_index < num_loaded_pairs;

               ++pair_index) {

            int thread_id = omp_get_thread_num();

            bool current_barcode_is_whitelisted = true;

            if (!mapping_parameters_.barcode_whitelist_file_path.empty()) {

                // increment variable for cache_hits

                bool curr_read_hit_cache = false;

                if (cache_query_result1 >= 0 || cache_query_result2 >= 0) {

                  cache_hits_for_batch++;

                  cache_hits_per_thread[thread_id]++;

                  curr_read_hit_cache = true;

                }

            // Update total read count and number of cache hits

            if (mapping_parameters_.is_bulk_data) 

            {

              // Sum up cache hits for each thread

              int cache_hits_for_batch = 0;

              for (int hits: cache_hits_per_thread) {

                cache_hits_for_batch += hits;

              }

              mapping_writer.UpdateSummaryMetadata(0, 

                                                   SUMMARY_METADATA_TOTAL, 

                                                   num_loaded_pairs);