Hi everybody,

I’m working with Seq2seq networks for NLP purposes and almost new to this Deep Learning area. Just have a question about matrix multiplication on Pytorch.

Suppose that I have these vectors:

`a = shape(2, 34, 200)`

```
b = shape (2,6, 200)
```

```
mask = shape(2,34)
```

mask is a 0-1 vector denoting specific tokens in a vector. (1: exists, 0: otherwise)

Here is the work I wanna do: I want to use mask vector to find the associated rows (denoted by 1 in mask) and multiply these rows by ‘b’ vector. As for this discussion, b vector associates with those rows in the a vector that has value 1 in the mask.