class_docstr: manages a local index, that does the coarse quantization and a set
  of sub_indexes. The sub_indexes search a subset of the inverted
  lists. The SplitPerListIndex merges results from the sub-indexes
class_docstr_tok: ["manages","a","local","index",",","that","does","the","coarse","quantization","and","a","set","of","sub_indexes",".","The","sub_indexes","search","a","subset","of","the","inverted","lists",".","The","SplitPerListIndex","merges","results","from","the","sub-indexes"]
code: def set_omp_num_threads(self, nt):
      faiss.omp_set_num_threads(nt)
      self.pool.map(
          lambda idx: idx.set_omp_num_threads(nt), self.sub_indexes
      )
  
imports: import time
  from faiss.contrib import rpc
  import combined_index
  import argparse
  from multiprocessing.pool import ThreadPool
  import faiss
  import numpy
label_desc: Use image node_id 3 for calling the SplitPerListIndex obj's underlying member method code with example usage: obj.set_omp_num_threads(nt) without return types