main.py failed

[gggh900]

https://github.com/yunjey/pytorch-tutorial/blob/master/tutorials/01-basics/pytorch_basics/main.py:

root@sriov-guest:~/dev-learn/gpu/pytorch/tutorial# python3 pytorch-main.py
tensor(2.)
tensor(1.)
tensor(1.)
w:  Parameter containing:
tensor([[-0.4404, -0.1190,  0.4829],
        [ 0.4956, -0.3760,  0.1435]], requires_grad=True)
b:  Parameter containing:
tensor([0.4760, 0.5684], requires_grad=True)
loss:  1.0722367763519287
dL/dw:  tensor([[-0.4775,  0.0949,  0.0065],
        [ 0.0698, -0.4295, -0.0664]])
dL/db:  tensor([0.3632, 0.3266])
loss after 1 step optimization:  1.0655767917633057
Downloading https://www.cs.toronto.edu/~kriz/cifar-10-python.tar.gz to ../../data/cifar-10-python.tar.gz
170499072it [00:32, 5230791.96it/s]
Extracting ../../data/cifar-10-python.tar.gz to ../../data/
torch.Size([3, 32, 32])
6
Traceback (most recent call last):
  File "pytorch-main.py", line 157, in <module>
    shuffle=True)
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/dataloader.py", line 270, in __init__
    sampler = RandomSampler(dataset, generator=generator)  # type: ignore[arg-type]
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/sampler.py", line 103, in __init__
    "value, but got num_samples={}".format(self.num_samples))
ValueError: num_samples should be a positive integer value, but got num_samples=0
root@sriov-guest:~/dev-learn/gpu/pytorch/tutorial#

[rollysys]

The main.py is not a complete example code, it's some code snippets.
You shoud implement your own "custom data loader", refer to torchvision.datasets.CIFAR10.
Your error is caused by null implementation of CustomDataset.

[lsnnt]

nnt@mycomp:~/pytorch-tutorial/tutorials/01-basics/pytorch_basics$ python3 main.py 
tensor(2.)
tensor(1.)
tensor(1.)
w:  Parameter containing:
tensor([[-0.0246,  0.4567, -0.4118],
        [ 0.1679, -0.5086, -0.3876]], requires_grad=True)
b:  Parameter containing:
tensor([0.0529, 0.2922], requires_grad=True)
loss:  1.949414610862732
dL/dw:  tensor([[-0.7870,  1.5242, -0.0795],
        [ 0.8206, -0.9073, -0.7711]])
dL/db:  tensor([-0.5564,  0.0907])
loss after 1 step optimization:  1.896445631980896
Files already downloaded and verified
torch.Size([3, 32, 32])
6
Traceback (most recent call last):
  File "/home/nnt/pytorch-tutorial/tutorials/01-basics/pytorch_basics/main.py", line 124, in <module>
    images, labels = data_iter.next()
AttributeError: '_SingleProcessDataLoaderIter' object has no attribute 'next'

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