code: def read_matches_files(
      data_dir: str, matches_file: str
  ) -> torch.Tensor:
      """Return a Tensor containing the ground truth matches
      Read the file and keep only 3D point ID.
      Matches are represented with a 1, non matches with a 0.
      """
      matches = []
      with open(os.path.join(data_dir, matches_file)) as f:
          for line in f:
              line_split = line.split()
              matches.append(
                  [
                      int(line_split[0]),
                      int(line_split[3]),
                      int(line_split[1] == line_split[4]),
                  ]
              )
      return torch.LongTensor(matches)
  
file_path: vision/torchvision/datasets/phototour.py
imports: import os
  from typing import Any, Callable, List, Optional, Tuple, Union
  import numpy
  import torch
  from PIL import Image
  from .utils import download_url
  from .vision import VisionDataset
label_desc: Use image node_id 3 for calling a global function with example usage: read_matches_files(data_dir, matches_file) and returns: torch