(tensor([3, 4]), tensor([1111, 4]))
tensor([[1., 1.],
[1., 1.]], requires_grad=True)
(tensor([1111, 4]), tensor([1111, 4]))
tensor(4., grad_fn=<SumBackward0>)
torch.Size([2, 2])
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
Cell In[27], line 1
----> 1 scalar.item()
ValueError: only one element tensors can be converted to Python scalars
(tensor([2]),
tensor([[1., 2.],
[3., 4.]]))
(torch.Size([1]), torch.Size([2, 2]))
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
Cell In[29], line 2
1 # 只有一个元素的tensor也可以调用`tensor.item()`
----> 2 tensor.item(), scalar.item()
ValueError: only one element tensors can be converted to Python scalars
tensor(3)
<SumBackward0 at 0x268464a44c0>
tensor([[1., 1.],
[1., 1.]])
让牛博看看你滴牛牛: 1.12.0+cpu
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
Cell In[65], line 4
1 # 构建 5x3 矩阵,只是分配了空间,未初始化
2 x = t.Tensor(5, 3)
----> 4 x = t.Tensor([[1,2],[3,4,5]])
5 x
ValueError: expected sequence of length 2 at dim 1 (got 3)