code: def main():
      parser = argparse.ArgumentParser(
          description="make index for a subset of the data"
      )
  
      def aa(*args, **kwargs):
          group.add_argument(*args, **kwargs)
  
      group = parser.add_argument_group("index type")
      aa(
          "--inputindex",
          default=workdir + "trained.faissindex",
          help="empty input index to fill in",
      )
      aa(
          "--nt",
          default=-1,
          type=int,
          help="nb of openmp threads to use",
      )
  
      group = parser.add_argument_group("db options")
      aa("--input", default=deep1bdir + "base.fvecs")
      aa(
          "--bs",
          default=2**18,
          type=int,
          help="batch size for db access",
      )
      aa("--i0", default=0, type=int, help="lower bound to index")
      aa(
          "--i1",
          default=-1,
          type=int,
          help="upper bound of vectors to index",
      )
  
      group = parser.add_argument_group("output")
      aa("-o", default="/tmp/x", help="output index")
      aa(
          "--keepquantizer",
          default=False,
          action="store_true",
          help="by default we remove the data from the quantizer to save space",
      )
  
      args = parser.parse_args()
      print("args=", args)
  
      print("start accessing data")
      src = produce_batches(args)
  
      print("loading index", args.inputindex)
      index = faiss.read_index(args.inputindex)
  
      if args.nt != -1:
          faiss.omp_set_num_threads(args.nt)
  
      t0 = time.time()
      ntot = 0
      for ids, x in rate_limited_iter(src):
          print(
              "add %d:%d (%.3f s)"
              % (ntot, ntot + ids.size, time.time() - t0)
          )
          index.add_with_ids(
              np.ascontiguousarray(x, dtype="float32"), ids
          )
          ntot += ids.size
  
      index_ivf = faiss.extract_index_ivf(index)
      print(
          "invlists stats: imbalance %.3f"
          % index_ivf.invlists.imbalance_factor()
      )
      index_ivf.invlists.print_stats()
  
      if not args.keepquantizer:
          print("resetting quantizer content")
          index_ivf = faiss.extract_index_ivf(index)
          index_ivf.quantizer.reset()
  
      print("store output", args.o)
      faiss.write_index(index, args.o)
  
file_path: faiss/benchs/distributed_ondisk/make_index_vslice.py
imports: import os
  import time
  import numpy
  import faiss
  import argparse
  from multiprocessing.pool import ThreadPool
label_desc: Use image node_id 5 for calling a global function with example usage: main() without return types