code: def read_ntype_partition_files(schema_map, input_dir):
      """
      Utility method to read the partition id mapping for each node.
      For each node type, there will be an file, in the input directory argument
      containing the partition id mapping for a given nodeid.
  
      Parameters:
      -----------
      schema_map : dictionary
          dictionary created by reading the input metadata json file
      input_dir : string
          directory in which the node-id to partition-id mappings files are
          located for each of the node types in the input graph
  
      Returns:
      --------
      numpy array :
          array of integers representing mapped partition-ids for a given node-id.
          The line number, in these files, are used as the type_node_id in each of
          the files. The index into this array will be the homogenized node-id and
          value will be the partition-id for that node-id (index). Please note that
          the partition-ids of each node-type are stacked together vertically and
          in this way heterogenous node-ids are converted to homogenous node-ids.
      """
      assert os.path.isdir(input_dir)
  
      # iterate over the node types and extract the partition id mappings
      part_ids = []
      ntype_names = schema_map[constants.STR_NODE_TYPE]
      for ntype in ntype_names:
          df = csv.read_csv(
              os.path.join(input_dir, "{}.txt".format(ntype)),
              read_options=pyarrow.csv.ReadOptions(
                  autogenerate_column_names=True
              ),
              parse_options=pyarrow.csv.ParseOptions(delimiter=" "),
          )
          ntype_partids = df["f0"].to_numpy()
          part_ids.append(ntype_partids)
      return np.concatenate(part_ids)
  
imports: import json
  import logging
  import os
  from itertools import cycle
  import constants
  import dgl
  import numpy
  import psutil
  import pyarrow
  import torch
  from dgl.distributed.partition import _dump_part_config
  from pyarrow import csv
label_desc: Use image node_id 1 for calling a global function with example usage: read_ntype_partition_files(schema_map, input_dir) and returns: np