IndexError: Target 42 is out of bounds.

IndexError: Target 42 is out of bounds.

想改语义分割的案例程序作为试验，进行图像分类，原本案例的分21类，我想分2类，请教一下是哪里出问题了呢？该怎么进行调整

  File "C:\Users\rong\Desktop\yu_yi_fen_ge_xun_lian.py", line 171, in <module>
    train()

  File "C:\Users\rong\Desktop\yu_yi_fen_ge_xun_lian.py", line 120, in train
    loss = loss_func(out, batch_y)

  File "D:\Anaconda-python\lib\site-packages\torch\nn\modules\module.py", line 1110, in _call_impl
    return forward_call(*input, **kwargs)

  File "D:\Anaconda-python\lib\site-packages\torch\nn\modules\loss.py", line 1163, in forward
    return F.cross_entropy(input, target, weight=self.weight,

  File "D:\Anaconda-python\lib\site-packages\torch\nn\functional.py", line 2996, in cross_entropy
    return torch._C._nn.cross_entropy_loss(input, target, weight, _Reduction.get_enum(reduction), ignore_index, label_smoothing)

IndexError: Target 42 is out of bounds. 

https://blog.csdn.net/hic51/article/details/118974247