AttributeError: Caught AttributeError in DataLoader worker process 0

Question

I have done some googling, and this error seems to commonly appear but I am unsure about how to solve it/ I am currently doing the PyTorch torchvision tutorial (https://pytorch.org/tutorials/intermediate/torchvision_tutorial.html) for segmentation. However, I am getting thrown the titular error:

Traceback (most recent call last):
  File "main.py", line 139, in <module>
    main()
  File "main.py", line 131, in main
    print_freq=10)
  File "/engine.py", line 26, in train_one_epoch
    for images, targets in metric_logger.log_every(data_loader, print_freq, header):
  File "/utils.py", line 180, in log_every
    for obj in iterable:
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/dataloader.py", line 521, in __next__
    data = self._next_data()
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/dataloader.py", line 1203, in _next_data
    return self._process_data(data)
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/dataloader.py", line 1229, in _process_data
    data.reraise()
  File "/usr/local/lib/python3.6/dist-packages/torch/_utils.py", line 425, in reraise
    raise self.exc_type(msg)
AttributeError: Caught AttributeError in DataLoader worker process 0.
Original Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/_utils/worker.py", line 287, in _worker_loop
    data = fetcher.fetch(index)
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/_utils/fetch.py", line 44, in fetch
    data = [self.dataset[idx] for idx in possibly_batched_index]
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/_utils/fetch.py", line 44, in <listcomp>
    data = [self.dataset[idx] for idx in possibly_batched_index]
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/dataset.py", line 311, in __getitem__
    return self.dataset[self.indices[idx]]
  File "main.py", line 64, in __getitem__
    img, target = self.transforms(img.target)
  File "/usr/local/lib/python3.6/dist-packages/PIL/Image.py", line 546, in __getattr__
    raise AttributeError(name)
AttributeError: target

I believe I have followed the tutorial completely, copying their code - I'm a bit unsure, therefore, why this error is arising. For a beginner who's trying to learn how to use ML in computer vision it's especially difficult to figure out what's going on here.

I don't know if this is important, but I'm running Python3 on Ubuntu.

Many thanks in advance for your help! :)

Answer 1

I think you mistyped the , with . in __getitem__ function of PennFudanDataset

Your version:

        if self.transforms is not None:
            img, target = self.transforms(img.target)

Tutorial:

        if self.transforms is not None:
            img, target = self.transforms(img, target)