Say that I have a tensor as follows:

```
a = torch.tensor([[1, 2, 3], [1, 2, 3]])
```

My problem is, what if I only have a look-up table of:

```
c = torch.tensor([0, 2, 3])
```

In which, for every out-of-index, I would like it to be assigned to index 0, such as *c[a]* will return

```
tensor([[2, 3, 0], [2, 3, 0]])
```

Does anyone know a function to do this?

Thanks for your help.