Hi everyone,

I’m a little confused with the substraction of the Tensor with different size, e.g. the Tensor(1, 3, 2) - Tensor(3, 1, 2).

```
import torch
import torch.nn as nn
tensor1 = torch.Tensor([[1, 2], [1, 2], [1, 2]])
tensor2 = torch.Tensor([[1, 1], [1, 1], [1, 1]])
a = tensor1.unsqueeze(0)
b = tensor2.unsqueeze(1)
result = a - b
```

After I excuted this code, the result says its size is (3, 3, 2), and the output of the substraction is just like each row of **a** minus the each dimension of **b**. However, I can’t undestand how this work. The **a**, in my mind, means the flat in the 3-d space. But the **b** is not the flat in this 3-d space. So, how could these two tensor work together?

Sorry about this stupid question.