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PyTorch DataLoader-"IndexError：次元0のテンソルにはインデックスが多すぎます"

CNNを実装してMNISTデータセット内の数字を識別しようとしていますが、データのロードプロセス中にコードでエラーが発生します。なぜこれが起こっているのか分かりません。

import torch
import torchvision
import torchvision.transforms as transforms

transform = transforms.Compose([
    transforms.ToTensor(),
    transforms.Normalize((0.5), (0.5))
])

trainset = torchvision.datasets.MNIST(root='./data', train=True, download=True, transform=transform)
trainloader = torch.utils.data.DataLoader(trainset, batch_size=20, shuffle=True, num_workers=2)

testset = torchvision.datasets.MNIST(root='./data', train=False, download=True, transform=transform)
testloader = torch.utils.data.DataLoader(testset, batch_size=20, shuffle=False, num_workers=2)

for i, data in enumerate(trainloader, 0):
    inputs, labels = data[0], data[1]

エラー：

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-6-b37c638b6114> in <module>
      2 
----> 3     for i, data in enumerate(trainloader, 0):
      4         inputs, labels = data[0], data[1]

# ...

IndexError: Traceback (most recent call last):
  File "/opt/conda/lib/python3.6/site-packages/torch/utils/data/_utils/worker.py", line 99, in _worker_loop
    samples = collate_fn([dataset[i] for i in batch_indices])
  File "/opt/conda/lib/python3.6/site-packages/torch/utils/data/_utils/worker.py", line 99, in <listcomp>
    samples = collate_fn([dataset[i] for i in batch_indices])
  File "/opt/conda/lib/python3.6/site-packages/torchvision/datasets/mnist.py", line 95, in __getitem__
    img = self.transform(img)
  File "/opt/conda/lib/python3.6/site-packages/torchvision/transforms/transforms.py", line 61, in __call__
    img = t(img)
  File "/opt/conda/lib/python3.6/site-packages/torchvision/transforms/transforms.py", line 164, in __call__
    return F.normalize(tensor, self.mean, self.std, self.inplace)
  File "/opt/conda/lib/python3.6/site-packages/torchvision/transforms/functional.py", line 208, in normalize
    tensor.sub_(mean[:, None, None]).div_(std[:, None, None])
IndexError: too many indices for tensor of dimension 0
pythonmachine-learningpytorch
3
nwker

trainsetが空でないかどうかを確認します。単純な印刷出力、trainloaderと同じです。それでも機能しない場合は、手動でmnistをロードすることをお勧めします

def load_mnist_labels(fnlabel):
f = gzip.open(fnlabel, 'rb')
f.read(8)
return np.frombuffer(f.read(), dtype = np.uint8)

def load_mnist_images(fnlabel):
f = gzip.open(fnlabel, 'rb')
f.read(16)
return np.frombuffer(f.read(), dtype = np.uint8)
0
user8426627